Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
SWUTC/96/72840-00003-1 4. Title and Subtitle 5. Report Date COMPENDIUM OF August 1996 GRADUATE STUDENT PAPERS ON 6. Performing Organization Code ADVANCED SURFACE TRANSPORTATION SYSTEMS 7. Author(s) 8. Performing Organization Report No.
9. Performing Organization Name and Address 10. Work Unit No. (TRAIS)
Transportation Engineering Program 11. Contract or Grant No. Civil Engineering Department Texas A&M University 12. Sponsoring Agency and Address 13. Type of Report and Period Covered
Southwest Region University Transportation Center Texas Transportation Institute 14. Sponsoring Agency Code The Texas A&M University System College Station, TX 77843-3135 15. Supplementary Notes
Faculty & Editor: Conrad L. Dudek
Mentors: Walter Dunn, Ginger Gherardi, Leslie Jacobson, Jack Kay, Colin Rayman and Tom Werner
16. Abstract
This document is the culmination of the sixth offering of an innovative transportation engineering graduate course at Texas A&M University entitled, "Advanced Surface Transportation Systems". The sixth offering of the course was presented during the summer 1996 term. As part of the course, a Mentors program was initiated as a means of providing the students with unique learning experiences. Six top-level transportation professionals from private enterprise and departments of transportation, who are leaders in their field and who have extensive experience with Intelligent Transportation Systems, were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems at the beginning of the summer term. Immediately following the Symposium, the students enrolled in the course participated in a Forum and a Workshop with the transportation professionals and course instructor. Based on mutual interests, each student was assigned to one of the professionals who served as a mentor (along with the course instructor) for the remainder of the summer term. Each student worked with his/her mentor and course instructor to identify a topic area and objectives for a term paper. In addition to discussions with the course instructor, the students (communicating via telephone, fax, e-mail, and mail) worked directly with the mentors throughout the term while preparing their term papers. The mentors returned to the Texas A&M University campus near the end of the summer term to hear and critique the students' presentations.
17. Key Words 18. Distribution Statement
Intelligent Transportation Systems, Advanced Traffic Management Systems, Advanced Travelers Information Systems, Congestion Management, Incident Detection, Electronic Toll Systems, Advanced Parking Information Systems, Variable Message Signs, HOV Facilities
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 454
Form DOT F 1700.7 (8-72) Reproduction of form and completed page is authorized COMPENDIUM OF
GRADUATE STUDENT PAPERS
ADVANCED SURFACE TRANSPORTATION SYSTEMS
AUGUST 1996
PREFACE
This document is the culmination of the sixth offering of an innovative transportation engineering graduate course at Texas A&M University entitled, "Advanced Surface Transportation Systems," which was presented during the 1996 summer term. As part of the course, a Mentors program provided the students with unique learning experiences. Six top-level transportation professionals from private enterprise and departments of transportation were invited to Texas A&M University to present a 1½-day Symposium on Advanced Surface Transportation Systems at the beginning of the summer term. Immediately following the Symposium, the students enrolled in the course participated in a Forum and a Workshop with the transportation professionals and course instructor. Based on mutual interests, each student was assigned to one of the professionals who served as a mentor (along with the course instructor) for the remainder of the summer term. Each student worked with his/her mentor and course instructor to identify a topic area and objectives for a term paper. In addition to discussions with the course instructor, the students (communicating via telephone, fax and mail) worked directly with the mentors throughout the term while preparing their term papers. The mentors returned to the Texas A&M University campus near the end of the summer term to hear and critique the students' presentations.
One important objective of the program was to develop rapport between the students and the transportation professionals. The opportunity for the students to communicate and interact with top transportation officials, who are recognized transportation engineering experts, was a key element to the students gaining the type of learning experiences intended by the instructor. Therefore, extra care was taken to encourage interaction through the Symposium, Forum, Workshop and social events.
Comparable to the previous years, this program was again extremely successful. The students had an excellent opportunity to interact directly for an extended period of time with top- level transportation professionals who are recognized for their knowledge and significant contributions both nationally and internationally.
Walter Dunn, Ginger Gherardi, Leslie Jacobson, Jack Kay, Colin Rayman, and Thomas Werner devoted considerable time and energy to this program. We are extremely grateful for their valuable contributions to the educational program at Texas A&M University.
The opportunity to bring top-level transportation professionals to the campus was made possible through financial support provided by the "Advanced Institute" at Texas A&M University which is sponsored by the University Transportation Centers Program of the U.S. Department of Transportation, and from funds received from the Zachry Teaching Program from the College of Engineering at Texas A&M University.
Gratitude and appreciation are expressed to Dr. Carroll Messer, Professor of Civil Engineering, Texas A&M University, who helped me pioneer this innovative graduate course in transportation engineering. Dr. Messer was a co-instructor for the course during the first two years it was offered. Other teaching commitments required his attention during subsequent summer terms.
ii Sandra Mantey, Senior Secretary with the Texas Transportation Institute, once again coordinated the Symposium and Workshop in a very efficient and professional manner.
Congratulations are extended to the transportation engineering graduate students who participated in this course. Their papers are presented in this Compendium.
Conrad L. Dudek Professor of Civil Engineering & Associate Director, SWUTC
iii MENTORS
WALTER DUNN
Mr. Walt Dunn is recognized for his expertise in freeway corridor traffic management, freeway incident management, and intelligent transportation systems (ITS). He is the founder and principal partner of Dunn Engineering Associates, a firm he started in 1982, which specializes in traffic management for both the private and public sectors.
Currently, he provides consulting engineering services on ITS projects for the Federal Highway Administration as well as the states of New York, New Jersey, Massachusettes, Rhode Island, Connecticut, Pennsylvania, Michigan, Wisconsin, and Tennessee.
Prior to starting Dunn Engineering Associates, Mr. Dunn worked for the New York State Department of Transportation for 16 years where he was director of the INFORM (Information For Motorists) project from inception through final design. INFORM is a corridor traffic management system designed to obtain better utilization of existing highway facilities. INFORM has been implemented in a 40-mile long highway corridor on Long Island, N.Y. as an operational demonstration.
Mr. Dunn successfully handled the traffic management of the 1995 and1986 U.S. Golf Open special events in Shinnecock Hills, New York. He is a co-author of the Freeway Incident Management Handbook and Communications Handbook for Traffic Control Systems for FHWA, Freeway Operations Project for the Transportation Research Board and "Freeway Management Systems for Transportation Efficiency and Energy Conservation" for Transport Canada.
On the national level, he is a member of the Freeway Operations Committee of the Transportation Research Board (TRB). He served as 1990 President of the Institute of Transportation Engineers (ITE) Met Section of New York and New Jersey, is a member of the American Society of Civil Engineers and Chi Epsilon and a licensed Professional Engineer in New York and New Jersey. Mr. Dunn is a Graduate of New Jersey Institute of Technology (B.S. in Civil Engineering) and Polytechnic University (M.S. Transportation Planning and Engineering).
iv GINGER GHERARDI
In July of 1989, Ginger became the first Executive Director of the Ventura County Transportation Commission (VCTC), which is also the Congestion Management Agency (CMA), the Airport Land Use Commission (ALUC), the Service Authority for Freeway Emergencies (SAFE), the Consolidated Transportation Service Authority (CTSA) and a member of the Southern California Regional Rail Authority (SCRRA). Under her leadership VCTC has adopted is Congestion Management Program, Airport Land Use Plan and implemented a centralized Transit Information System (Dial-A-Route). The Commission implemented Metrolink commuter rail service in 1992, including construction of three rail stations (one of these as a result of the 1994 Northridge Earthquake) and two layover facilities. This year VCTC purchased the Santa Paula Branch Railroad Line for development and use as a bicycle/trail/rail heritage corridor.
Ginger was responsible for the expansion of the countywide call box system, including the development of a cellular phone program for physically challenged residents and the installation of TTY/TTD devices for the hearing impaired and the development and distribution of countywide bicycle maps. Two years ago VCTC implemented a new countywide bus system, VISTA, linking municipal systems throughout the County that was selected as one of the outstanding examples of the use of Congestion Mitigation Air Quality (CMAQ) funds in the United States. VCTC is currently participating in a federal “Smart Card” demonstration project known as the Ventura County Passport. Most recently, VCTC implemented a website “Go Ventura” (http://www.goventura.org) that not only contains needed transportation information but provides personalized On-Line Transit Routing, a first in the United States.
Between September 1985 and July 1989, Ginger was the Manager of the Highway/TSM Programs for the Los Angeles County Transportation Commission. Among other things, she was responsible for developing the 10 Year Highway Plan, “On the Road to the Year 2000"; the Los Angeles “Smart” Corridor Demonstration project; the implementation of a SAFE to upgrade the call box system and the development of a countywide bicycle map.
Prior to working at LACTC, Ginger worked for the Southern California Association of Governments, managing the Transportation Development Act Programs. She is a former Simi Valley City Councilwoman, Mayor and teacher. Ginger is a member of the Institute of Transportation Engineers (ITE), the Santa Paula Rotary and is on the Board of Directors of the Santa Paula Boys and Girls Club. She currently serves as the National President of the Women’s Transportation Seminar (WTS). Ginger received B.S. and M.S. degrees from Pratt Institute in Brooklyn, New York.
v LES JACOBSON
Mr. Les Jacobson is an expert in traffic management systems, especially freeway management and high occupancy vehicle systems. He received his Bachelor's degree in Civil Engineering from the University of Washington and his Master's Degree in Civil Engineering at the University of California at Berkeley.
Mr. Jacobson is the Traffic Services Manager for the Northwest Region of the Washington State Department of Transportation. He is responsible for all traffic engineering and electronic maintenance functions in the Region. He has been with the WSDOT since 1977 and has spent most of his career dealing with traffic management issues, especially freeway operations, HOV systems and more recently ITS. He was an integral member of the team that implemented the ramp metering system in Seattle in 1981 and supervised the operation of the Traffic Systems Management Center (TSMC) from 1983 through 1984. It was during his tenure at the TSMC that the first major HOV lane was opened on Interstate 5 in Seattle.
Mr. Jacobson spent five years at the Washington State Transportation Center (TRAC) at the University of Washington where he managed the WSDOT's Urban Systems Branch. He developed the WSDOT's Freeway and Arterial Management Effort (FAME). The program focused on research and implementation in the area of HOV systems, incident management and traffic management systems. He initiated WSDOT's ITS program, Venture Washington, during his tenure at TRAC.
Mr. Jacobson is responsible for the operation of the Seattle area's freeway HOV system. He sits on the WSDOT HOV Policy Task Force and was one of the major contributors to the WSDOT HOV Policy. He is currently involved in several HOV planning efforts. He is a registered professional engineer in Washington State. He is a member of the Institute of Transportation Engineers and the ITS Council, and is the secretary of TRB HOV Systems Committee. He chairs the ITS America ATMS Committee and is a member of the Coordinating Council and Planning Committee. He chairs or sits on several NCHRP research panels, and teaches Traffic Flow Theory at the University of Washington.
vi JACK L. KAY
Mr. Jack L. Kay specializes in providing technical consulting with an emphasis in Intelligent Transportation Systems, in the areas of traffic control; traffic engineering and research; and implementation and funding program development. He has over 30 years of experience in traffic engineering, including over 25 years as a consultant to public and private agencies.
Mr. Jack L. Kay is CEO of the 270 person transportation consulting firm JHK & Associates, an SAIC company. Mr. Kay is/was involved as responsible officer, in the Maryland State Highway project known as CHART; Advantage I-75 project; for the evaluation of the operation of the INFORM System; and the FHWA project entitled "Investigation of Successful Implementation, Operation, and Maintenance of Traffic Control Systems". As member of the joint venture Mr. Kay is responsible for the overall strategic perspective and review of the multi-faceted projects encompassed within the I-95 Coalition.
Mr. Kay served as Project Director of the Smart Corridor Demonstration Project Conceptual Design Study; the California Department of Transportation project entitled the Statewide Smart Corridor Study; and for the implementation of a sophisticated traffic control system in the City of Anaheim. Previous traffic control system projects in which Mr. Kay has been involved include systems in the cities of Los Angeles, Baltimore, Phoenix, Tucson, Hartford, Alexandria, Salt Lake City, and the FHWA UTCS program. Mr. Kay has also worked extensively as an advisor on traffic and transportation projects for the World Bank.
Mr. Kay is the Immediate Past Chair of the Board of Directors of ITS America. He also is a fellow of the Institute of Transportation Engineers and chaired that organization's IVHS Advisory Committee during the committee's formation. Mr. Kay is a member of the Transportation Research Board's Freeway Operations Committee and the IVHS Task Force. Mr. Kay also serves as Section Chair of TRB's Group 3, Section A - Facilities and Operations. This section includes many of the TRB committees involved in IVHS related activities.
vii COLIN RAYMAN
Mr. Colin Rayman is recognized as one of the premier practitioners in the field of Intelligent Transportation Systems (ITS) with special emphasis in advanced traffic management systems. He has over 22 years of professional and management experience with the Ontario Ministry of Transportation (MTO) and with the private sector. He has developed transportation policy and programs for the Ontario government and has also served as a senior technical advisor to foreign governments as well as managed transportation infrastructure projects in Ontario and internationally.
Mr. Rayman is the Manager of the Intelligent Transportation Systems Office of the Ontario Ministry of Transportation in Toronto. He is responsible for providing leadership in the development of a comprehensive ITS policy and strategy for the Province of Ontario.
Prior to his most recent assignment, Mr. Rayman served in a number of capacities with MTO. As Director of the Transportation Operations Branch, he was responsible for overall direction and administration of the MTO’s highway maintenance and traffic operations sub-program and developed policy related to the Ministry’s transportation corridor permitting function. As District Maintenance Engineer in Toronto, he was responsible for summer and winter maintenance in MTO’s largest and most urbanized district. As Head of the Freeway Traffic Management Section, he was responsible for freeway traffic management systems implementation in the Province of Ontario. During this time, he successfully commissioned two new systems (including the COMPASS system).
During a two and a half year stint with the private sector, he managed a consulting practice in California. Project experience included Traffic Management Center Upgrades, Traffic Operations System designs and Fiber Optic Communication System designs in Los Angeles and Orange County for Caltrans. He also advised on the I-25 BUS/HOV Transportation Management System for the Regional Transportation District in Denver, CO and acted as a Specialist Consultant to the University of Minnesota for the development of an automatic incident detector.
He is the Vice-Chair of the ITS Roundtable of the Transportation Association of Canada; Chair of Research & Development Subcommittee of the ITS America ATMS Steering Committee; a Member of the Coordinating Council of ITS America; a Member of AASHTO’s Advanced Transportation Systems Operations Subcommittee; a Member of the Institute of Transportation Engineers; a Member of the Professional Engineers of Ontario; and also a former member of TRB’s Freeway Operations Committee. He is a registered professional engineer in Ontario.
viii THOMAS C. WERNER
Mr. Thomas C. Werner is an expert in traffic engineering and safety management, with a strong professional interest in freeway operations and ITS. He attended Canisius College in 1962 and received his Bachelors Degree in Civil Engineering at the University of Detroit in 1965 and MBA at State University of New York, Buffalo in 1973 and is a registered professional engineer in New York State.
Mr. Werner is the Director of the Traffic Engineering and Safety Division of the New York State Department of Transportation headquartered in Albany. He is the manager and administrator of statewide traffic engineering and highway safety programs for the Main Office and eleven Regional Offices. Mr. Werner has twenty years experience with the main office Traffic Engineering and Safety Division of NYSDOT. Prior to the Albany assignment, Mr. Werner served nine years in the Buffalo Regional Planning, Design and Traffic Safety offices working on traffic analyses for major expressway projects in the Western New York area. Mr. Werner has been involved in all phases of the Information for Motorists (INFORM) project on Long Island-- a state of the art freeway corridor traffic surveillance and control system. He also currently manages ATMS, ATIS, ARTS, and AVCS elements of NYSDOT's Intelligent Transportation Systems (ITS) program.
Mr. Werner is active in many professional organizations including TRB Freeway Operations Committee and several AASHTO Committees. He has served on the FHWA Expert Panel for Operations and Maintenance of Traffic Control System and was the recipient of an FHWA scholarship for participation in the 1991 ITE European IVHS study tour. Mr. Werner is the NYSDOT representative on TRANSCOM and the I-95 Corridor Coalition. He currently serves as Panel Chairman to NCHRP Project 7-13, "Quantifying Congestion" and is Vice-Chairman of the AASHTO Standing Committee on Highway Traffic Safety.
Most recently, Mr. Werner accepted a four-year appointment to C13 Committee on Road Safety, Permanent International Association of Road Congress (PIARC) and to AASHTO’s ITS Standards Development Steering Group.
Prior to his current NYSDOT assignment, he served as Regional Director for the eight county Albany Capital District area.
ix TABLE OF CONTENTS
IMPLEMENTATION ELEMENTS FOR CONVERSION OF A GENERAL PURPOSE FREEWAY LANE INTO A HIGH OCCUPANCY VEHICLE (HOV) LANE by Matthew E. Best ...... A-1
ADDRESSING SECURITY ISSUES IN ITS/ATMS by Christopher L. Brehmer ...... B-1
IMPEDIMENTS TO THE EFFECTIVE USE OF PORTABLE VARIABLE MESSAGE SIGNS AT FREEWAY WORK ZONES by David M. Halloin ...... C-1
ELECTRONIC TOLL COLLECTION INFORMATION: IS PERSONAL PRIVACE PROTECTED? by Douglas J. Holdener...... D-1
THE USE OF ELECTRONIC TOLL AND TRAFFIC MANAGEMENT SYSTEMS FOR FREEWAY INCIDENT DETECTION by A. Bowman Kelly...... E-1
BARRIERS TO IMPLEMENTATION OF SIGNAL PRIORITY SYSTEMS FOR TRANSIT OPERATIONS: LESSONS LEARNED FROM ADVANCED TRAFFIC MANAGEMENT SYSTEMS by David A. Noyce...... F-1
CHALLENGES AND GUIDELINES FOR IMPLEMENTING ADVANCED PARKING INFORMATION SYSTEMS IN THE UNITED STATES FOR DAILY DOWNTOWN TRAFFIC by Kelly Parma...... G-1
EXAMINATION OF A UNIFORM SMART CARD FOR ELECTRONIC TOLL COLLECTION AND TRANSIT FEES by Clint Schuckel...... H-1
THE USE OF THE INTERNET AS AN EFFECTIVE TOOL FOR DISSEMINATING TRAVELER INFORMATION by Lee Anne Shull ...... I-1
A COMPARISON OF REAL-TIME FREEWAY SPEED ESTIMATION USING LOOP DETECTORS AND AVI TECHNOLOGIES by Joe van Arendonk ..... J-1
APPENDIX ...... APPEN-1
x vi IMPLEMENTATION ELEMENTS FOR CONVERSION OF A GENERAL PURPOSE FREEWAY LANE INTO A HIGH OCCUPANCY VEHICLE (HOV) LANE
by
Matthew E. Best
Professional Mentors Leslie N. Jacobson, P.E. Washington State Department of Transportation
and
Ginger Gherardi Ventura County Transportation Commission
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas
August 1996 SUMMARY
Conversion of a general purpose freeway into a High Occupancy Vehicle (HOV) lane can be an alternative to infrastructure addition for HOV system implementation. Research indicates (10,11) that lane conversion is technically feasible if sufficient HOV usage and minimal main lane congestion occur from the first day of operation forward. The purpose of this research is to determine what elements are required for inclusion in an implementation plan for a lane conversion to HOV once technical feasibility has been determined.
HOV marketing is meant to heighten public awareness of the purpose and operation of HOV facilities while encouraging their use. The inclusion of the general public, local decision-makers, and the local media in a marketing campaign are important elements of successful HOV implementation (6). These elements also apply to the successful implementation of lane conversion to HOV.
This research investigated five HOV lane conversion projects:
C The Santa Monica Freeway-Los Angeles, California; C The Dulles Toll Road-Northern Virginia; C Interstate 90-Seattle, Washington; C Interstate 80-Northern New Jersey; and C Interstate 270-Maryland.
The Santa Monica and Dulles projects are considered failures while the Interstate 80 and 90 projects are considered successful. Interstate 270 will be implemented in 1997. State Highway 44 was not a conversion project but had similar characteristics. From these case studies and the literature review, implementation elements were identified.
The following elements should be included in an implementation plan for lane conversion to HOV:
C Technical Feasibility; C Early Public Outreach; C Strong Institution Arrangements; C Inclusion of Law Enforcement Agencies; C Open Relationships with the Media; and C Project Opening Timing.
These implementation elements are applied to a hypothetical application which is described in the section entitled “Hypothetical Application.”
A-ii TABLE OF CONTENTS
INTRODUCTION ...... A-1 Research Motivation ...... A-2 Objective ...... A-2 Organization of Report ...... A-3
BACKGROUND ...... A-4 HOV Conversions ...... A-4 HOV Marketing ...... A-5
STUDY METHODOLOGY ...... A-7 Study Design ...... A-7 Data Collection ...... A-7 Data Reduction ...... A-7 Data Analysis and Application ...... A-7
STUDY RESULTS ...... A-8 The Santa Monica Freeway-Los Angeles, California ...... A-9 Project Description ...... A-9 Target Audience ...... A-9 Institutional Arrangements ...... A-11 Educational/Public Relations ...... A-11 Continuing Efforts ...... A-11 Conclusions ...... A-11 The Dulles Toll Road-Northern Virginia ...... A-12 Project Description ...... A-12 Target Audience ...... A-13 Institutional Arrangements ...... A-13 Educational/Public Relations ...... A-13 Continuing Efforts ...... A-14 Conclusions ...... A-14 Interstate 90-Seattle, Washington ...... A-15 Project Description ...... A-15 Target Audience ...... A-15 Institutional Arrangements ...... A-15 Educational/Public Relations ...... A-17 Continuing Efforts ...... A-17 Conclusions ...... A-17 Interstate 80-Northern New Jersey ...... A-18 Project Description ...... A-18 Target Audience ...... A-18 Institutional Arrangements ...... A-18 Educational/Public Relations ...... A-20 Continuing Efforts ...... A-20
A-iii Conclusions ...... A-20 Interstate 270-Maryland ...... A-21 Project Description ...... A-21 Target Audience ...... A-21 Institutional Arrangements ...... A-23 Educational/Public Relations ...... A-23 Continuing Efforts ...... A-23 Conclusions ...... A-23
IMPLEMENTATION GUIDELINE ELEMENTS ...... A-24 Technical Feasibility ...... A-24 Early Public Outreach ...... A-24 Strong Institution Arrangements ...... A-24 Inclusion of Law Enforcement Agencies ...... A-24 Open Relationships with the Media ...... A-25 Project Opening Timing ...... A-25
HYPOTHETICAL APPLICATION ...... A-26 Technical Feasibility ...... A-26 Traffic Effects ...... A-26 HOV Improvements ...... A-28 Secondary Concerns ...... A-28 Institutional Arrangements ...... A-28 Public Involvement ...... A-30 Implementation ...... A-30
CONCLUSIONS ...... A-32
ACKNOWLEDGMENTS ...... A-33
REFERENCES ...... A-34
APPENDIX ...... A-37
A-iv INTRODUCTION
In response to increasing traffic congestion, limited finances, and greater environmental concerns, the Intermodal Surface Transportation Efficiency Act of 1991 (1) suggests the use of High Occupancy Vehicle (HOV) treatments as a method to increase the person-moving capacity of a corridor. HOV facilities are designed to provide a travel time savings and more predictable travel times for buses, vanpools, and carpools. This in turn provides an incentive for commuters to change to a travel mode in which they can utilize the facility. By moving more people in fewer vehicles, congestion and pollution are reduced while the person-moving capacity of a corridor is increased (2).
HOV freeway lanes have generally been added to a freeway corridor as an increase in physical capacity. Lanes can exist in a separate facility inside or outside the freeway right-of-way, on concurrent lanes not physically separated from general purpose traffic, or on contraflow lanes. Contraflow lanes usually are lanes which are “borrowed” from the off-peak direction of flow and are separated by some sort of changeable treatment, such as pylons or the Movable Concrete Barrier System (2,3). In lieu of adding HOV capacity to freeway corridors, urban areas around the nation are beginning to examine options for converting general purpose freeway capacity into HOV facilities.
HOV freeway systems have been successfully implemented across North America. The following is a partial listing of HOV facilities in North America. It is a good example of how geographically dispersed the varieties of HOV facilities are in North America (4).
C Ottawa, Ontario and Pittsburgh, Pennsylvania have systems of busways on exclusive right-of- way. C Washington, DC, Houston, Texas, and Minneapolis, Minnesota have barrier separated, reversible HOV facilities in the median of freeways. C Los Angeles, California and Houston, Texas have barrier separated HOV facilities in the median of freeways which operate in two directions. C Seattle, Washington, Miami, Florida, and Hartford, Connecticut have HOV facilities in the far left lane of freeways which are not barrier separated from general purpose traffic. C New York City and Dallas, Texas operate contraflow HOV facilities using drop-in cones and the Movable Concrete Barrier System, respectively.
As of January 1996, there were freeway HOV facilities operating in 24 urban areas in North America covering approximately 1,400 lane-miles. New facilities are planned in 29 urban areas for an addition of over 2,100 lane-miles (4).
As a network of HOV lanes expands across an urban area, the benefits of connecting individual corridor HOV lanes into an HOV network are significant. Currently, many HOV systems are discontinuous. HOV trips which use more than one corridor must enter general purpose traffic (and congestion) to switch between HOV facilities, reducing the potential benefits of carpool and transit use. The completion of an HOV network through the implementation of HOV treatments on arterial streets and circumferential freeways give the growing suburb-to-suburb work trip travel time savings through carpool and transit use. Thus by approaching HOV improvements from a system-
A-1 wide approach, advantages which were initially realized only on a corridor scale can be expanded to the entire urban area.
Research Motivation
Many links in an HOV network may not have been completed because they would not be cost-effective to construct. Certain corridors may have cross-section and right-of-way restrictions which would not support an affordable addition of HOV capacity. In such locations where the expense of infrastructure construction or right-of-way acquisition is greater than the benefits of increased travel time savings for HOVs, other solutions must be found. A do-nothing scenario would not be acceptable if it is assumed that development of an HOV network is societally important. Location of an HOV facility on an adjacent corridor may be one logical alternative if such a facility could offer a sufficient level of time savings. The best technical solution may be the conversion of existing general purpose freeway lanes into HOV lanes.
Lane conversion has been supported by environmental groups as the only “environmentally sound” way to provide HOV treatments (5). The argument is that worsened conditions for low- occupancy vehicles will lead to a greater incentive for motorists to shift to higher capacity, more environmentally friendly modes. This point of view has not been shared by the millions of commuters who feel that HOV use, through carpooling or transit, is not an acceptable option. Lane conversion as a method of HOV implementation has been strongly opposed by the motoring pubic when increased congestion in the general purpose lanes is the result (6,7,8).
The conversion of general purpose freeway lanes into HOV lanes has had a difficult past. An early example of a conversion failure is the Santa Monica “Diamond” Lane. In 1976, this project converted the left general purpose freeway lane into an HOV lanes on the Santa Monica Freeway (Interstate 10) in Los Angeles, one of the busiest freeways in North America. The project was successful in that more people were moving through the corridor than before conversion, but congestion was intense in the general purpose lanes leading to driver frustration and an increased accident rate. Public opposition ran high, and the project was terminated by court order after 21 weeks(9).
The Dulles Toll Road is a more recent example of difficulties with lane conversion. In this 1992 case, newly constructed sections of the Dulles Toll Road in northern Virginia were constructed with the left lane designated as HOV 3 (three or more persons per vehicle). During the construction period, while the HOV lanes were discontinuous, the Virginia Department of Transportation (VDOT) allowed general purpose traffic access to the HOV lanes until the project was complete. Once construction was completed and the lanes converted to HOV 3 lanes, congestion in the two general purpose lanes was high. Political and public opposition to the HOV lanes culminated in an act of the Governor of Virginia to remove the occupancy requirements from the lane a mere month after the project was opened (9).
Objective
Once the technical assessment of a project has been completed and a section of freeway lane has been identified for conversion to HOV, little guidance exists on how to go about implementing
A-2 the conversion. From the case studies presented in this report, important elements for inclusion in implementation guidelines will be identified. The objective of this research is to develop a set of elements which should be included in a general purpose lane conversion to HOV lane implementation effort. This report does not recommend specific courses of action to be taken. Each conversion project will be different due to local variations.
Organization of Report
This report is organized into seven sections. The first section, “Introduction,” includes an objectives of HOV lanes, a discussion of the research motivation for this report, explanation of the scope of the research and the organization of the report. The second section, “Background” provides a literature review regarding HOV conversions and HOV marketing issues. “Study Methodology,” the third section, includes documentation of the study design, data collection, data reduction, and data analysis of this research effort. Case study reviews are included in the forth section which is entitled “Study Results.” The fifth section, “Implementation Guideline Elements” includes a listing and discussion of the implementation guideline elements needed for the implementation of a general purpose freeway lane conversion to HOV. The sixth section includes a discussion of a hypothetical conversion implementation. The Final section is “Conclusions.”
A-3 BACKGROUND
HOV Conversions
The first step in any HOV conversion project is to prove it technically feasible. Although the goal of an HOV freeway lane is to increase the person-moving capacity of a corridor (2), an increase in person-moving capacity cannot be the only measure of effectiveness used. The early success of a project is dependent more on the acceptance of the public than on traffic operation effects. If significant congestion is left on the mainlanes and the converted lane appears “empty” after the change is made, the project is likely to fail from public and political pressure no matter what the traffic numbers indicate (9). Technical feasibility must be determined from a set of criteria which measure overall corridor performance as well as the effects of conversion on general purpose and HOV operations.
Recognizing the importance of opening day success to the continued public and political support of an HOV project, as well as the more traditional goals of mode shift and increased people moving capacity, Dr. A. May (10) has developed guidelines to screen freeway sections in urban areas for promising HOV lane conversion sites. The screening technique consists of eight major steps:
1. Input of Available Basic Information; 2. Prediction of Day 1 Traffic Performance; 3. Prediction of Mode Shift; 4. Re-Evaluation of Traffic Performance after Mode Shift; 5. Prediction of Future Growth; 6. Re-Evaluation of Traffic Performance After Future Growth; 7. Prediction of Further Mode Shift; and 8. Re-Evaluation of Traffic Performance After Further Mode Shift.
Dr. May’s technique (10) includes six quantifiable criteria as well as qualitative issues which are used to gauge the success of a conversion project. The criteria are as follows:
1. Minimum Flow in the HOV Lane; 2. Maximum Flow in the HOV Lane; 3. Maximum Flow in the Mixed-Flow Lane; 4. Differential in Level of Service Between the Mixed-Flow Lanes and the HOV Lane; 5. Differential in the Number of Persons Carried per Lane Between the Mixed-Flow Lanes and the HOV Lane; 6. Minimum Travel Time Savings in the HOV Lane; and 7. Qualitative Secondary Criteria.
Criteria one and three take in to account “empty lane syndrome” (appearance that the HOV lane is empty) and congestion in the remaining general purpose lanes. These items tend to test the political will of the implementing agencies and local politicians. If there is insufficient use of the HOV lane or increased congestion in the general purpose lanes, the public outcry may be sufficient to shut down the project.
A-4 Criteria two, four, five, and six measure the success of the HOV lane in providing travel time savings and stability to HOV users over the life of the project. If the improvement is not sufficient or cannot be sustained, conversion may not be the manner in which the goals of increased person- moving efficiency and mode shift should be pursued.
The secondary criteria include such considerations as the existence of upstream or downstream HOV facilities and the feasibility of conversion in the opposite direction/peak period.
HOV Pre-Design Studies Task 2.3 (11) suggests the conditions which best support HOV lane conversion from general purpose lanes:
C The lane should carry more person trips with faster times than an average general purpose lane; C General purpose traffic should not be subjected to a level-of-service worse than E; C General purpose traffic should not divert to parallel arterial streets; C The converted lane should show considerable cost savings over construction of a new lane; C The converted lane should be implemented much sooner than an added lane would be programmed without the disruption of construction activities; and C Public surveys and affected agencies should show positive community and political support for HOV lane conversion.
HOV Marketing
The High Occupancy Vehicle (HOV) Lane Marketing Manual (9) is a compilation of HOV marketing issues. Through the use of case studies, elements of a sound marketing approach to HOV lane implementation is presented. The HOV Lane Marketing Manual does not specifically cover the issues involved with HOV lane creation by conversion of general purpose freeway lanes.
HOV marketing can accomplish the following (9):
C Heighten public awareness of ridesharing as an option; C Increase public confidence in HOV strategies; C Develop accurate expectation for HOV facilities; C Advertise the opening of HOV lanes; C Educate drivers in the use of HOV lanes; C Promote immediate use of HOV lanes; C Create awareness of support facilities (i.e. park-and-ride lots, ridematching services); and C Provide updated accounts of HOV lane time savings and usage.
The HOV marketing process should begin early in the planning process. Market research at early planning stages can often aid the planner by helping to “define the social and political atmosphere in which the project will be set, identifying key stake holding groups, and assembling information on other HOV projects with similar goals and objectives.”(9) This information is vital to a marketing campaign and important to successful planning and design efforts.
As the implementation date of an HOV project approaches, marketing efforts should increase in scale and scope. This phase calls for the release of media materials, advertisements, press
A-5 conferences, and promotional events such as ribbon cuttings. After implementation, marketing should continue to support the implementation of support facilities such as park and ride lots and any changes in operational procedures (9).
Little research has discussed marketing issues involved exclusively with general purpose freeway lane conversion to HOV lanes. Studies by Gard, Jovanis, Narasayya, and Kitamura (7) and JHK & Associates (11) summarize findings from two independent surveys of public opinion regarding HOV lane conversions from general purpose freeway lanes.
Gard, et.al. (7) surveyed 1,085 residents of California (575 in the San Francisco Bay Area, 510 in Southern California). The results of the survey indicated that residents of California generally preferred that a new HOV lane be constructed (30%) or the left hand shoulder be converted (40%). 30 percent of those surveyed indicated that they preferred that an HOV lane be created from conversion of an existing general purpose lane on the freeway driven most frequently. In-depth focus group interviews found consistent results with the broader telephone surveys, however focus group participants who did not support lane conversion “vowed to fight” any conversion efforts.
A similar study was undertaken in the Seattle area (11). When given the option of HOV lane construction or HOV lane conversion from general purpose lanes, 49 percent of the respondents favored new construction compared to 26 percent who favor lane conversion. 58 percent of respondent expressed negative opinions about HOV conversion while 33 percent expressed positive opinions toward conversion.
A conclusion of both of these studies is that the general public is generally supportive of HOV networks. The Seattle study asked: “How would you feel if the freeway you use most were to have one lane converted to an HOV lane so that the whole distance you normally drive would have one continuous HOV lane?” 62 percent of respondents strongly supported or somewhat supported this statement, which is inconsistent with the response of 58 percent of respondents who had negative opinions about HOV conversions. The authors of the report speculate that the benefits of a continuous HOV facility had a positive impact on some respondents.
A-6 STUDY METHODOLOGY
Study Design
This research efforts consisted of three major steps. First a literature review was conducted including references on HOV conversions from general purpose freeway lanes and HOV marketing. A summary of the literature review was included in the previous section labeled “Background.” Much of the information collected in the literature review aided the formation of case study reviews of HOV conversion projects.
Second, case study reviews of HOV conversion projects were formed. Information for the case studies was gathered from the literature review and from case study interviews. The interviews were conducted with professionals from agencies which were involved with the projects.
Third, recommendations for HOV lane conversion implementation have been made. Using the information gathered from the literature review and case study reviews, conclusions on what elements should be included in an HOV conversion implementation plan will be presented. Implementation elements are applied to a hypothetical application.
Data Collection
Information on HOV conversions was collected from existing literature, interviews with involved agencies, and project documentation provided by interview contacts. Interviews were conducted with seven transportation professionals at various agencies. The interviews were administered with the use of an interview question form (see appendix) to keep interviews focused on specific issues regarding the implementation of HOV conversion from general purpose freeway lanes.
Data Reduction
The data collected from the telephone interviews and conversations, literature review, and project summary reports were summarized in project case studies. The issues of target audience concerns, institutional arrangements, education and public relation concerns, and continuing efforts were summarized and are included in the “Study Results” section of this paper. Important conclusions from each case study were included with the case study write-ups.
Data Analysis and Application
The important conclusions from each case study included in this research effort are included with the case study. From these conclusions, guideline elements were identified to assist responsible agencies in the implementation of HOV conversions. These elements are included in the “Implementation Guideline Elements” section of this report. The guideline elements are applied to a hypothetical lane conversion implementation effort.
A-7 STUDY RESULTS
This section summarizes five HOV projects which involved the conversion of a general purpose freeway lane into an HOV lane. Each case study includes a description of the project and implementation efforts as well as conclusions. The five projects summarized are as follows:
C The Santa Monica Freeway-Los Angeles, California; C The Dulles Toll Road-Northern Virginia; C Interstate 90-Seattle, Washington; C Interstate 80-Northern New Jersey; and C Interstate 270-Maryland.
Table 1 summarizes the contacts and a brief note on their contributions.
Table 1. Interview Contacts.
Contact Agency Contribution Heidi Stamm Pacific Rim Resources Discussion of HOV marketing issues. Maryland State Highway Partial interview concerning Interstate Heidi Van Luven Administration 270 conversion project. Maryland State Highway Completed interview concerning Robert Ritter Administration Interstate 270 conversion project. New Jersey Department of Interview concerning Interstate 80 Barbara Fischer Transportation conversion project. Washington State Department Discussion of Interstate 90 conversion David Berg of Transportation project in Seattle. Virginia Department of Interview concerning Dulles Toll Road Joan Morris Transportation project. Virginia Department of Rail Discussion of Dulles Toll Road and Charlene Robey and Public Transportation HOV marketing issues.
A-8 The Santa Monica Freeway-Los Angeles, California
Project Description
Under pressure from the Environmental Protection Agency to take positive actions toward reducing vehicle miles of travel in the Los Angeles area, the California Department of Transportation (CALTRANS) initiated the Santa Monica Freeway Diamond Lanes in March 1976. CALTRANS, in conjunction with the California Highway Patrol (CHP) and local bus operators, reserved the median lane of the 19 km (12 mi) Santa Monica Freeway (Interstate 10) connecting the City of Santa Monica with Downtown Los Angeles for buses and carpools carrying three or more persons. Figure 1 shows the boundaries of the project as it was publicized by CALTRANS. The HOV lanes reduced the number of general purpose directional lanes on what was the busiest freeway in North America from four to three (9).
Traffic congestion and accidents increased markedly (accidents up 225%) in the mainlanes of the freeway from day one of operation forward. Speeds of general purpose traffic decreased and were less stable after the implementation of the project. HOV violation rates were high, and incidents such as paint bombs used to obliterate HOV pavement markings and nails thrown into the HOV lane occurred. The local newspaper, television, and radio coverage was extremely negative. After 21 weeks of operation, the Diamond Lanes project was terminated prematurely by court order.
The project succeeded in increasing the number of carpools (up 65%) and the number of transit riders (up 225%). Persons using an eligible mode were able to save a small amount of time over the length of the corridor during the peak period over those in a single occupant mode (two to three minutes over pre-conversion travel time, four to six minutes over general purpose traffic after conversion). The benefits of decreased fuel consumption and vehicle emissions failed to materialize during the project’s shortened life (9).
Target Audience
The marketing campaign was conventional in nature. It sought to increase ridesharing by targeting the general audience of corridor users. The marketing plan included a prediction of public outcry during the early stages of the project due to the operational problems involved with removing a lane of the busiest freeway in the nation from general purpose traffic (9).
Little pre-project marketing research was undertaken prior to the Santa Monica Diamond Lanes project. Other HOV projects had been implemented prior to Santa Monica, and it was felt HOV issues were beginning to be understood by the motoring public. The continuation of Interstate 10 east of downtown Los Angeles, the San Bernardino Freeway, contains the El Monte busway which was converted to HOV traffic around the same time as the Santa Monica Diamond Lanes project (4). The Santa Monica Freeway itself operated with HOV ramp meter bypass lanes. With little pre-project research, the marketing plan was not focused to any particular group to improve the success of implementation.
A-9 Figure 1. Overview of the Santa Monica Diamond Lane Project (9).
A-10 Institution Arrangements
Many issues made the creation of stable institutional relationships difficult during this project. Central authority for transportation planning in the Los Angeles area was fairly weak at the time and transportation activities were often done in a non-cooperative manner. A change in philosophy, policies, and personnel at CALTRANS compounded the problems. The new administrators at CALTRANS were left with a project which they did not initiate or fully understand. Finally, the project was set to occur during an election year. Many politicians saw more political benefit in using the project as a campaign issue rather than working for it success.
CALTRANS worked with the two local transit agencies and the California Highway Patrol to implement and enforce the lanes.
Education/Public Relations
The marketing campaign sought to induce public acceptance of improved mass transportation through lane conversion, to enhance the chances of project success through public information and education, and to increase bus patronage and carpooling through new and improved services in the area (9). A press conference began the marketing campaign a couple of weeks before opening. Efforts included radio, newspaper, and television ads, billboards, freeway message signs, and commuter handouts. The handout information included reasons for the Diamond Lanes (environmental, congestion), how to use the lanes, rules for lane use, alternate route descriptions, and bus and carpool information.
Continuing Efforts
In response to the public and political outcry following implementation of the Diamond Lanes, CALTRANS took a more aggressive marketing approach by hiring a public relation consultant. This new campaign included appearances at public forums, contacts to downtown employers, formation of “The Friends of Diamond Lanes” group, and quick responses to press coverage deemed inaccurate or misleading.
These efforts did not succeed and the project was prematurely terminated. “The Friends of the Diamond Lanes” were not particularly useful in counter-balancing the great number of foes of Diamond Lanes. CALTRANS lost much credibility when project foes generated their own traffic and vehicle occupancy data regarding the diamond lanes which was contradictory to CALTRANS’ data.
Conclusions
It is difficult to conclude that any marketing campaign adjustments could have saved the Santa Monica Diamond Lanes project from early termination. Operationally speaking, taking an already congested freeway and reducing its physical capacity by 25% is a dangerous proposition. Data show that the HOV lanes were an operational success at the same time that the conversion project as a whole was a resounding failure. One extensive survey reported that “eighty-six percent of the corridor drivers surveyed--including the majority of carpoolers--felt that the Diamond Lanes were either harmful or of no benefit whatsoever.” (9)
A-11 Key places where the marketing efforts failed the project include the lack of pre-project research, lack of a target audience to focus marketing efforts on, timing of the project during an election year and during a CALTRANS administration change, and the confrontational nature of relations with the press. Greater efforts to hold together a coalition of agencies and public officials, more effective carpool inducement techniques such as ride matching and employer incentives to increase lane utilization during the early stages of the project, and greater communication with the public through public meetings, press releases, and telephone question lines have been suggested as way which the project could have been improved (9).
It is important to note that HOV is currently widely excepted in the Los Angeles area. Although the Santa Monica experience set back HOV planning in the area for several years, an extensive HOV network has been established and continues to grow.
The Dulles Toll Road-Northern Virginia
Project Description
The Dulles Toll Road is a 19 km (12 mi) facility paralleling the Dulles Airport Access Road running from Dulles Airport to Tysons Corner Virginia (see Figure 2). It is a major artery for residents of Fairfax and Loudoun Counties in Northern Virginia traveling into Washington DC. It is a state owned toll road administered by the Virginia Department of Transportation (VDOT). VDOT was given permission by the state legislature to expand the capacity of the toll road from two to three directional lanes, with the provision that the added lane be reserved for carpools carrying three or more people during the peak periods (12).
During construction, a 11 km (7 mi) stretch of the new lane was completed prior to the remaining sections. VDOT decided that the lane should be opened to general purpose traffic until the remainder of the lanes were finished. Once construction was completed, the remainder of the newly constructed lanes were opened to general purpose traffic while other arrangements, such as toll booth modifications were completed. For approximately two months, general purpose traffic enjoyed free flow conditions on three lanes for the entire length of the Dulles Toll Road. Traffic levels increased due to latent demand and diversions to the facility (13).
Figure 2. Dulles Toll Road and Carpool Lanes (12).
A-12 The day after Labor Day was chosen as the opening day for HOV operations. The lanes were reserved for vehicles carrying three or more persons. During operation, accidents and congestion on the Dulles Toll Road and parallel facilities increased while toll revenues dropped. An anti-HOV campaign was lead by U.S. Representative Frank Wolf, representing Northern Virginia and most of the users of the Dulles Toll Road. Mr. Wolf attached an amendment to the 1992 Federal Highway Appropriations Bill which in effect made HOV provisions illegal on the Dulles corridor. The Governor of Virginia, Douglas Wilder, suspended the project before the federal legislation was signed to avoid having Virginia State highway policy dictated by the Federal Government. HOV restrictions were in place on the Dulles Toll Road for 33 days.
VDOT did not plan for this HOV lane to be a conversion project. Specific marketing efforts were not aimed toward problems caused by converting a lane, but were aimed at general HOV issues. HOV had been successfully operated in Northern Virginia for years prior to Dulles, including one of the nation’s most successful HOV facility, the Shirley Highway. With their past successes, VDOT did not feel it was necessary to create a particularly elaborate marketing plan for the Dulles Toll Road HOV lanes project (13).
Target Audience
The general audience was corridor users. It was found through preliminary research that seven percent of Toll Road users met the 3-person carpool requirement before the project opened. The traffic stream also included eight percent 2-person carpools. Because of the long nature of trips taken on the Toll Road, and supported by these occupancy number, VDOT felt satisfied that ridership existed to make the lane work. VDOT’s estimates of day one HOV volume was 300 carpools an hour. This volume is light enough to give the appearance to commuters in congested mainlanes that the HOV lane is “empty” (9).
Institution Arrangements
The project had strong support from a legislative mandate that the lanes be built as HOV lanes. Also the Fairfax County Board of Supervisors supported the project. The Metropolitan Washington Airports Authority, which owns and operates the Dulles Airport Access Road located in the median of the Dulles Toll Road, took a neutral approach to the project. Little was done to contact local decision-makers or community groups (13).
The failure to build support for the lane among local decision-makers was especially harmful. Congressman Frank Wolf was especially vocal against the HOV lanes (9).
Education/Public Relations
The messages of the marketing campaign were to inform commuters that the lanes were coming and to build support for the use of HOV lanes. The campaign was not particularly aggressive in disseminating these messages (13).
A-13 Four methods were used to distribute this information (9):
1. Burma Shave signs (consecutive signs which together carry a message) were used with catchy phrases to inform drivers HOV lanes were coming and to encourage drivers to use them; 2. Local Metro buses were extensively outfitted with signs publicizing that the HOV lanes were coming 3. Brochures were developed to be distributed by the Loudoun and Fairfax County ridesharing offices; and 4. Opening day ceremonies were held which included a “barrel bashing” ceremony were attendees could smash orange construction barrels with a sledgehammer to recognize the end of a long construction period.
Loudoun County officials forbade their ridesharing office from distributing the brochures.
The relationship between the press and VDOT was poor. The media generally accepted HOV lanes, but not on the Dulles Toll Road. VDOT did little to court this important constituency. Especially damaging to VDOT were traffic reporters who criticized the project during their on-air traffic reports (9).
Continuing Efforts
Few efforts were made to save the Dulles Toll Road HOV lanes given the short time which they were in operation. Major changes in VDOT’s procedures for marketing and implementing HOV lanes were and are currently being undertaken (14). Six months after the removal of the HOV requirements on the Dulles Toll Road, VDOT successfully opened extended HOV lanes on Interstate 66 to the south of the Dulles Toll Road. An extensive marketing campaign was undertaken in the support of this project.
Conclusions
The Dulles Toll Road experience is very similar to the Santa Monica Diamond Lanes in that general purpose freeway lanes were taken away from general purpose traffic and reserved for HOVs on busy a freeway. They both occurred during a congressional election year, allowing them to be used as a political issue. They both occurred in regions where complex jurisdictional issues exist. The main difference is that the Dulles HOV lanes were originally designed as HOV lanes and were only temporarily converted to general purpose flow. This conversion was in place long enough for commuters to enjoy travel time savings, resulting in increased traffic volumes from induced and latent traffic demands.
The opening day chosen for the project was detrimental to its implementation. Placing opening day on the traditional busiest travel day of the year, the day after Labor Day, could only make day one congestion in the main travel lanes worse.
A-14 Interstate 90-Seattle, Washington
Project Description
Interstate 90 is one of the two east-west freeways in the Seattle metropolitan area. Interstate 90 connects the City of Seattle with the suburban City of Bellevue via a bridge over Lake Washington. Crossing Lake Washington, Interstate 90 carries three directional general purpose lanes and a two lane, reversible median HOV roadway. The section immediately to the east of the HOV roadway was identified as a future HOV corridor in the HOV core freeway system plan. With four directional general purpose lanes and little to no congestion problem, construction of new lanes in this section was years away (15).
Interstate 90 had a lane balance problem. Four lanes of freeway in the westbound direction feed three general purpose lanes and a two lane reversible HOV roadway to cross Lake Washington. The same situation existed in reverse in the eastbound section. Excess capacity existed in the section to the east of the reversible HOV roadway, and good operations could be maintained with general purpose traffic limited to three lanes. It was decided that the conversion of the left most freeway lane could be a quick and inexpensive way to add an HOV lane to the facility. The conversion could take place years before new construction could be considered (15).
The project involved conversion of 8 km (5 mi) of general purpose lane and the addition of 5 km (3 mi) of HOV lane through re-striping in the westbound (inbound) direction. The eastbound lanes were converted for the entire 13 km (8 mi) length (see Figure 3). Estimated cost of adding 13 km (8 mi) of HOV lanes in both directions of this freeway was $70 million. The conversion project cost the Washington State Department of Transportation (WSDOT) a total of $100,000 (15).
Target Audience
A specific group of facility users was not targeted by the marketing plan of this project (16). The general commuting public on Interstate 90 and in the Seattle area was the broad audience. Local decision-makers, agency officials, city and county council members, and transportation officials were targeted.
After studies indicated that more could have been done to target a narrower audience than the general public. Studies indicate that slightly more commuters were against the conversion than in favor, and that among those against the conversion, younger commuters, commuters from high income groups, and single occupant vehicle drivers were most opposed to lane conversions (8). A more effective campaign may have focused efforts on these groups, however given the success of this implementation effort, it was not of vital importance.
Institution Arrangements
The support of local officials was sought as an important means to bolster support for the lane conversion project. Local decision-makers and officials were involved in the preliminary stages of project development before the decision to convert the lanes was made. Letters of support for the conversion project were provided by local governments.
A-15 Figure 3. Interstate 90 Conversion Plan, Seattle, Washington (15).
A-16 Meetings were held with the city councils and engineering staffs of bordering areas. Local legislative representatives were kept informed of project developments and the results from the public involvement process. The region’s metropolitan planning organization, the Puget Sound Regional Council, and sub-regional planning committees were also informed of the technical, public, and political progress of the project.
In general, institution arrangements made for this project were successful in bolstering support. By keeping all parties who may have stake in the project informed and involved, none found a political motive to block it (15).
Education/Public Relations
An Environmental Assessment (EA) was performed for this project. The EA started the public involvement process through federally required public meetings. Initial public meetings generated little public interest and were poorly attended. To garner greater public interest in the project, an advertisement campaign including newspaper advertisements was initiated. The newspapers were also solicited to publish articles about the project. Radio advertisements were aired and traffic reporters were contacted to brief them on the project and solicit their opinions (15).
The advertisement campaign was geared to an all day open house/public hearing. Although there was some strong opposition to the conversion proposal, most citizens who attended the public meeting were either in support or indifferent to the project (15).
Continuing Efforts
The University of Washington was contracted to perform an ongoing analysis of the project. Both the operational aspects of the project and the marketing aspects were analyzed and specific recommendations for improving the process for future HOV conversion projects were made (8). It was concluded that the lane conversion did not have adverse effects on the operation of Interstate 90. Marketing suggestions for future projects focused on the better definition of a target audience.
Marketing efforts have continued throughout the region. These efforts have been augmented by information available on the World Wide Web (17).
Conclusions
The Interstate 90 project was one of the first documented successful HOV conversion projects. The primary reason for successful implementation of the HOV conversion project was the correction of the lane balance problem on Interstate 90. The bottleneck section on Mercer Island metered flow to the east so that excess capacity was available for conversion to exclusive use by HOV traffic. General purpose traffic was not subject to negative impacts from the conversion.
Initiation of the EA process led to the early inclusion of the general public. Through this process the public understood the project’s purposes and goals. The EA process also aided the determination of the public attitude toward the project.
A-17 The success of this project indicates that early and intense public involvement in a technically feasible project can aide successful implementation. Also, strong institutional arrangement which include local stakeholders in the decision making process improve the chances of successful implementation.
Interstate 80, New Jersey
Project Description
The Interstate 80 corridor serves diverse commuting patterns in northern suburban New Jersey. While in the midst of a five year, 15 km (9 mi) reconstruction and lane addition project, the New Jersey Department of Transportation (NJDOT) initiated a feasibility study for opening a 17 km (10.5 mi) directional HOV lane on Interstate 80, including all of the new lane under construction and a 2 km (1.5 mi) segment east of the construction zone in which the general purpose lanes would be converted to HOV operation (see Figure 4). In 1991, the western 7 km (4 mi) of the new lane were opened to general purpose traffic. Another section of the new lanes was completed prior to the finish of the project. It was decided to leave this section closed until the entire project was finished in early 1994 (18).
In 1994, the full 17 km (10.5 mi) HOV lane was opened for HOV use only. This included 9 km (5.5 mi) of general purpose lane which was converted from general purpose to HOV use. Supported by an extensive marketing campaign, the implementation of the HOV lane did not meet significant public resistance and is currently operating successfully in terms of person moving capacity and HOV travel time savings (19).
Target Audience
The target audience of the public campaign was fairly broad. Commuters of the freeway were the primary target, but considerations of the impacts on non-users were also included. Attitudinal surveys were administered to 1,201 adults living in the freeway corridor. Additionally, 23 business leaders and community representatives were interviewed (18).
Institution Arrangements
A steering committee was formed to help guide NJDOT through implementation. It was important that consensus be reached and that the institutional stakeholders sign off on the project. The members of the steering committee included:
C The Federal Highway Administration; C Traffic Management Associations; C New Jersey Turnpike Authority; C New Jersey TRANSIT; C Morris and Bergen County Engineering and Planning Departments; and C The New Jersey State Police.
A-18 Figure 4. Interstate 80 HOV Lane Operations, New Jersey (18).
A-19 These stakeholder agencies were involved so that their concerns would be met and the project could be successfully moved forward with full consensus. The process helped form a partnership with the State Police to ensure effective enforcement of the lanes would be possible. New Jersey TRANSIT’s participation initiated the start-up of two new corporate shuttle bus routes from park and ride lots into Morris County office parks. The Traffic Management Associations supported the project by promoting HOV lanes through the formation of ridesharing arrangements. The Federal Highway Administration provided technical support and funding. The full support of the regional transportation agencies allowed a united front to support the successful completion of the project. The arrangements also enabled positive statements regarding the HOV project to come from sources outside NJDOT (18).
The executive interviews were an important tool in constituency building. The decision- makers interviewed were given the opportunity to provide input into the project and were made available at press conferences where they expressed their support for the project (18).
Education/Public Relations
The public relations campaign emphasized the viability of HOV as an overall traffic improvement device. Discussion of air quality issues was included in the campaign. The issue of lane conversion was not mentioned. NJDOT hoped acceptance of the HOV concept at the end to five years of disruptive construction activities would make the lane conversion a non-issue (18,19).
A major media blitz was used to disseminate the message of the HOV lane conversion. Radio and television advertising, billboards, buttons, a newsletter, press releases, radio talk shows, and a speaker’s forum which offered presentations to local community groups, professional organizations, and employers were used to carry the message of the HOV improvement to the general public (18,19).
Continuing Efforts
The original marketing efforts continued for sometime after the lanes were opened. The main concerns from the public have been with operational issues involved with the HOV lanes rather than issues with the lane conversion. There have been some complaints from commuters who think it is unfair to have been subjected to five years of construction and associated congestion without any benefits from the end product.
Conclusions
The Interstate 80 HOV lane has been successfully implemented and is currently operating with high ridership in the HOV lanes (6300 persons in 2500 vehicles during the morning peak) and considerable travel time savings (10 to 15 minutes in the morning peak). The lane was generally acceptable to the commuting public. Strict enforcement of the lanes by the State Police has lead to a low violation rate (5-10%) which has helped preserve public respect of the HOV treatment (19).
Reasons for success have been attributed to the success of early consensus building between the many agencies and decision-makers in the area. This eliminated dissention “at the top” which
A-20 has helped kill HOV projects in the past. Inclusion of the State Police in this process along with provisions for funding enforcement have lead to the low violation rate. Early information to the public through outreach surveys and the placement of “Future HOV” signs above the lane to be converted were also helpful (19).
Corridor specific issues led to successful implementation. The large number of two person carpools which existed in the corridor prior to the opening of the HOV lane treatments led to full utilization of the HOV lane soon after implementation, thus avoiding “empty lane syndrome” which has killed other HOV projects.
Interstate 270-Maryland
Project Description
Interstate 270 is a major radial freeway extending from the northwest corner of the Capital Beltway (Interstate 495) into the suburbs located in Montgomery County, Maryland. Prior to its termination at the Capital Beltway, the freeway splits into two legs, one directing traffic onto the Beltway going west and south, and the other directing traffic east. The freeway serves the large suburban communities of Rockville and Gaithersburg, Maryland.
A major, four-phase reconstruction project has been in progress on Interstate 270 for many years. Additional capacity has been and is currently being added to the freeway for general purpose and HOV traffic. Phase I and II involved the addition of HOV lanes to the two legs near the Capital Beltway terminus of the freeway. Phase III added a lane between State Highway 118 and the freeway split. Phase IV will add an HOV lane from the projects northern boundary at State Highway 121 to State Highway 118 (20) (see figure 5).
The phase III section of addition lane is part of a future HOV system in the corridor. At the time phase III construction was completed, insufficient ridership existed for the lane to be opened as HOV. The lane was opened to general purpose traffic with signing above which indicates that the lane is a future HOV lane. The lane will open sometime in early 1997 when the phase IV HOV lane is ready to open (20,21).
Target Audience
It has been decided that the marketing campaign for both the opening of the newly constructed phase IV lanes and the conversion of the phase III lanes be focused toward the general public corridor users. Public efforts will begin a couple of months before opening of the lanes. The Maryland State Highway Administration (SHA) is attempting to receive as much return as possible from their marketing dollar and will wait to initiate full scale marketing until the opening of the project is closer (21).
Efforts will start in mid-August aimed at employer groups to begin carpool formation efforts. The employer groups will help coordinate the formation of carpools among their employees. This will have the effect of educating the commuters about carpooling as well as contributing to the operational success of the project.
A-21 Figure 5. I-270 HOV Projects Under Construction (22).
A-22 Institution Arrangements
SHA has formed a coalition with the following groups:
C The Montgomery County Department of Transportation; C The Montgomery County Planning Department; C The Maryland State Police; and C Transportation Management Associations (TMA).
The county agencies are needed to approve of a project within their jurisdiction. The TMAs will assist with ridesharing efforts to improve HOV ridership in the corridor. The reasoning behind not opening the lane to HOV traffic initially was a lack of ridership. Unless ridership is improved, success of the project can not be guaranteed (21).
Education/Public Relations
Flyers, brochures, and press releases are the main forms of media planned. The information will include the benefits of ridesharing and instructions for use of the lanes. Also planned are contacts and promotions with local traffic reporters. SHA has maintained good relations with traffic reporters in the past. Their cooperation has been deemed important to the success of HOV implementation.
For the three years which the lane has been open to general purpose traffic, signs above the lane state that the lane is a future HOV lane. The hope is that showing the motoring public that the commitment exists to eventually open this lane as an HOV lane, commuters will not feel they have “ownership” over the lane and that the current arrangement is temporary (21).
Continuing Efforts
A monitoring program will be put in place to determine the success of the operational and public opinion aspects of the project. No large marketing or media blitz is planned for the implementation of the program. Any marketing efforts will be reactive, the contents of which will be determined at the time needed (21).
Conclusions
SHA hopes that the use of the “future HOV” signs and the time of conversion occurring at the same time that the balance of the project is opened will allow implementation to proceed smoothly. Currently there is excess capacity in the section to be converted and opening day mainlane congestion is not expected to be severe.
A-23 IMPLEMENTATION GUIDELINE ELEMENTS
Elements which should be included in an implementation plan are listed below:
• Technical Feasibility; • Early Public Outreach; • Strong Institution Arrangements; • Inclusion of Law Enforcement Agencies; • Open Relationships with the Media; and • Project Opening Timing,
Technical Feasibility
The research highlighted in the “Background” section of this paper is a good tool for measuring the technical feasibility of a conversion project. Conversion projects which cause severe congestion in the general purpose lanes or result in HOV lanes which appear empty are likely to fail. A sound screening process should be used to assess the traffic effects which a conversion project is likely to have. No amount of marketing can save a project which is not technically feasible. This is especially true when commuters are subjected to high congestion by conversion of one of “their” lanes for use by others.
Early Public Outreach
Starting the outreach early and providing mechanisms for public comment on the plans are important when considering lane conversion. Federal regulation requires public participation in the transportation planning process (1), but a higher degree of participation may be needed for an emotionally charged issue such as the conversion of general purpose lanes to HOV lanes. If public opinion is stacked against a conversion project, and early marketing efforts are ineffectual in altering public opinion, alternative implementation options may be necessary to the achieve goals of an HOV project.
Strong Institution Arrangements
Inclusion of all agencies and local officials will help a project succeed. Local agencies and officials are much closer to the local general public and have a closer feel for the concerns of their constituents than a state or federal agency could have. Also, the agendas of local agencies and officials can not be ignored. The benefits of using local agencies and officials as spokespersons and cause champions are immense. These persons tend to be trusted and their support can turn public opinion in favor of project methods and goals.
Inclusion of Law Enforcement Agencies
Any HOV project depends on strict enforcement for its operational success, but enforcement is also important from a public opinion standpoint. A lane where violators go unpunished while law- abiding citizens wait in traffic is likely to be unpopular with the law-abiding public. By making the
A-24 law enforcement agencies stakeholders in a project, they are more likely to provide extra effort toward an important effort, enforcement, which state transportation agencies have little control over.
Open Relationships with the Media
It is never clear whether public opinion leads to similar press coverage or vice versa, but it is clear that a relationship exists. Clear and honest relationships with the press should be established. By providing the media with full information, reporters will be in a position to report events accurately and reduce the need for an investigation to unwrap the “mysteries” of a conversion project. Providing full information to the media will not assure that press coverage will always be positive, but it will ensure accurate reporting and a higher level of discourse.
A special group of reporters who must be kept informed of project details and developments are the on-air traffic reporters. These persons witness traffic congestion daily and are in a position to express support or criticism of a project and implementing agency during their on-air traffic reports. Their reports are trusted by commuters and if an attacking approach is taken, commuters stuck in traffic congestion are more likely to take actions to fight the project.
Project Opening Timing
The timing of a conversion is very important. Implementing projects during a lower traffic demand period can lead to smoother operations during the critical early days of the project. Also, avoiding implementation during years where politicians are looking for popular causes to fight will help the chances of success. Any even numbered year when Congressional elections are taking place should be avoided. Local experience should dictate what year project implementation should precede.
A-25 HYPOTHETICAL APPLICATION
The following section contains a description of a hypothetical conversion project of a general purpose freeway lane into an HOV lane. The fictional Springfield Metropolitan Area is the setting for the conversion which will be undertaken by the State Department of Transportation (DOT). Figure 6 illustrates the corridor which will have the far left lane in each direction converted to HOV operation and its location within the Springfield freeway and HOV system. The heavy dashed lines represent existing concurrent flow HOV lanes located in the far left lane of the freeways. All operate with occupancy requirement of two or more persons per vehicle and express bus service is available in the US 93 and Interstate 13 corridors. The gray solid line represents the location of the proposed lane conversion. This section of Interstate 213 was expanded ten years ago to four general purpose lanes in each direction. The section of Interstate 213 to the northeast of the conversion section under-went a similar expansion project which was finished three years ago. However, due to growing air quality and traffic congestion concerns in the metropolitan area, this section of Interstate 213 was rebuilt to include three general purpose lanes in each direction and a left lane concurrent flow HOV lane.
All HOV lanes in the metropolitan area operate in the peak period only. On US 93 and Interstate 46, the inbound HOV lane is open in the morning peak while the outbound HOV lane is open in the evening peak. Interstate 213 does not have a strong peak direction, and both the existing HOV lane and future converted HOV lane will operate in both directions during peak periods.
Large suburban activity centers (SAC) have developed at the junctions of freeways in the region. Three such SACs are located where the radial freeways (Interstate 13, Interstate 46 and US 93) intersect the circumferential freeway (Interstate 213). The urban area central business district (CBD) is located at the intersection of Interstate 13 and Interstate 46. Trends in the metropolitan area are shifting toward an increased portion of commute trips being taken to the SACs. Also, residential areas to the west along Interstate 46 in the city of Webster have doubled in size in the last five years and are expected to continue to grow at a rapid rate. With a shift in the urban area toward more dispersed commute trips taken to the SACs instead of the CBD, traffic congestion on Interstate 213 is expected to be a major problem in the twenty-year planning horizon.
Technical Feasibility
Traffic Effects
The conversion section of Interstate 213 is currently operating at level of service (LOS) D during the peak period. After conversion, this section will operate at LOS E. This condition satisfy the maximum general purpose volume criteria as stated by May (10).
HOV traffic on the section is estimated to be 600 vehicles per hour on the first day of operation. A high number of existing HOVs travel the corridor between the Interstate 46 HOV lane in the south and the US 93 and Interstate 213 HOVs in the north. Two hundred additional HOVs are expected to form with the lane conversion. A volume of 800 vehicles per hour is low enough to maintain free- flow conditions on the HOV lane and high enough to avoid the appearance that the lane is empty.
A-26 Figure 6. Springfield Freeway and HOV System.
A-27 HOV Improvements
HOV traffic is expected to gain a couple of minutes along the length of the conversion section. Considerable travel time savings are expected for HOVs as traffic growth occurs in the corridor over the next twenty years. There will be a large LOS differential between general purpose traffic and HOV traffic (LOS E vs. LOS B). It is expected that the HOV lane will carry more persons on the first day of operation than any of the other lanes.
Secondary Concerns
The conversion section will complete an important link in the regional HOV system since it connects the three major SACs with a continuous HOV lane. As traffic congestion increases along Interstate 213 from continued development in the urban area and increasingly dispersed travel patterns, greater benefits in the form of travel time savings will be available to persons utilizing transit or carpooling.
Although travel time savings for HOVs in this section will be initially small, converting the lane at a time when the operational affects on general purpose traffic are small is more politically feasible than converting the lane once congestion has become a problem. By converting the lane now, the person-moving efficiency of the corridor will be improved and the need for costly capacity improvements will be delay or eliminated.
Institutional Arrangements
Table 2 lists the institutional arrangements which will be made prior to implementing the Interstate 213 conversion. Included in Table 2 is a short description of the purpose or role which each institutional partner is expected to play in the conversion implementation.
The cities which the Interstate 213 conversion project passes through are expected to provide ridesharing efforts and general support. General support includes approval of the project running through their jurisdiction, public support for the plan, and availability to answer questions on behalf of the DOT. These cities will be partners with the DOT before the final decision to convert is made. Each city will be required to coordinate their efforts regarding the conversion project with the DOT and the other cities. This is the most important institutional arrangement made and will be the first one forged.
The Springfield Metropolitan Planning Organization (MPO) will be consulted for conformance of the HOV conversion project with regional transportation plan. The MPO will also provide support in locating funding for the conversion effort.
The Regional Transit Authority (RTA) will also be a partner in the Interstate 213 conversion project from the earliest stages. RTA will operate supporting transit services in the Interstate 213 corridor including express bus service connecting the SACs and CBD with park-and-ride lots located along Interstate 46 and US 93 in Brighton and Webster.
A-28 The City of Webster, which is not directly impacted by the Interstate 213 conversion will be solicited to aide the DOT, RTA, and other cities with ridesharing efforts. Given that much of the current and future residential development is occurring in the City of Webster, the cooperation of that city will be sought in improving transit and carpool ridership.
The State Police will be included early in the design stages of the conversion effort. Their views and concerns regarding the converted HOV lane will be solicited and incorporated into the design. Enforcement plans will be approved by the State Police before the DOT moves forward to implementation.
Members of the local media will be informed of the project and its goals early in the planning process. Complete information will be provided to encourage full and accurate reporting of the conversion project. On-air traffic reporters will be solicited for their opinions on the proposed conversion project. By giving them input early into the process, they will have an opportunity to inform their listeners of the upcoming conversion. It is recognized that cooperative relationships with the press will not eliminate negative coverage, however accurate, and fair reporting should be the result.
Table 2. Institutional Arrangements for Hypothetical Application.
Institution or Group Expected Role City of Springfield Ridesharing efforts and general support City of Brighton Ridesharing efforts and general support City of Granger Ridesharing efforts and general support Springfield Region MPO Cooperative planning efforts and financial support Regional Transit Authority (RTA) Transit improvements City of Webster Ridesharing efforts State Police Enforcement provisions Springfield press corp Information exchange On-air traffic reporters Information exchange SAC Business groups Outreach to employers Brighton Heights Neighborhood Assoc. Public outreach South Granger Neighborhood Assoc. Public outreach Rep. Fred Bear Local political support
A-29 The Business groups representing companies which hold office and retail space in the suburban activity centers in the corridor will be contacted to inform them of project details and goals. There help in organizing rideshare and transit efforts among their employees will be solicited.
Neighborhood Associations along the corridor will be contacted as an early method of public outreach. Presentation will be made to the groups and projects goals will be discussed. Concerns and comments of the local residents will be solicited and considered in the implementation effort. Also included is U.S. Representative Fred Bear, whose Congressional District contains the Interstate 213 corridor, the cities of Webster, Granger, and Brighton and the western part of the city of Springfield. He will be solicited to represent his constituents and express his own comments and concerns.
Public Involvement
The public involvement process will begin early. Contacts with local neighborhood associations and politicians will be the first step. Public feedback will be encouraged. A World- Wide-Web page will be published on the Internet with project information and a electronic mailbox for the public to send comments and concerns regarding the project to the DOT. A telephone hotline will also be created for the public to call in with questions or comments. The telephone number will be placed on highway signs in the Interstate 213 corridor as well as at selected location on the US 93 and Interstate 46 corridors. Also, placards reading “Future HOV Lane” will be placed above the lane to be converted on Interstate 213.
Approximately four months prior to the conversion, television, radio, and newspaper advertisements will be run on the local media. This advertising campaign will include descriptions of the project and its goals. The advantages of HOV, including improved travel times and environmental improvements will also be highlighted. The number of advertisements run per week will increase as the implementation date approaches.
The week before implementation will start with a press conference to explain project details and goals and to answer questions from the press corp. During this week, open house forums will be held in the SACs and at other sites along the corridor. The open houses will provide an opportunity for the public to view material regarding the conversion project and ask questions of DOT and city officials.
Implementation
The project will be implemented during the Tuesday of the first week of August, 1997. This date is traditionally the day of the year in Springfield when traffic is lowest. 1997 is a year where few local officials are up for re-election in Springfield, thus avoiding the chances of a politicalization of the conversion issue.
During the weeks and months following the lane conversion, the DOT will monitor conditions to determine the level of HOV ridership and operational conditions of the mainlanes. Surveys will be distributed to residents in the area a month following implementation to poll opinion
A-30 regarding the conversion. The World-Wide-Web page will be maintained and incorporated into a larger Springfield Transportation Information Page. The telephone question line will remain open for four months following implementation and then will be merged with the standard DOT question line.
As a final public outreach effort, DOT and city officials will meet with the neighborhood groups following implementation to determine their opinions of the conversion and answer any follow-up questions.
A-31 CONCLUSIONS
Thorough marketing is important to the success of any HOV project. HOVs are facilities are normally built at the public expense and serve a select group of commuters. Their successful implementation depends on convincing the public that they are either a benefit to society or a minimal cost to themselves. This is especially true for lane conversion when a lane is being “taken away” from the general purpose traffic and “given” to a select group.
This paper is not meant to support conversions of general purpose lanes into HOV lanes as a preferred method of HOV implementation. The assertion that successful HOV projects must force people into carpools by subjecting general purpose traffic to intense congestion, as suggested by the Chesapeake Bay Foundation (5) and the Sierra Club (23) is not realistic. The political realities of transportation improvements overwhelm any attempts at forcing behavioral changes. The American public has a love of the automobile (9), they are resistant to any changes to take away their freedom to use their private automobile, and to use it alone. Politicians are aware of this fact and will exploit it as a means to their own political agendas. Only technically strong conversion projects which do not cause extreme congestion in the general purpose lanes and do not suffer from “empty lane syndrome” should be pursued. The projects chosen for implementation must be supported by an aggressive marketing campaign, including the elements listed in this report, to ensure that “taking” a lane from general purpose traffic and giving it to HOV traffic is made acceptable to the motoring public.
A-32 ACKNOWLEDGMENTS
The author wishes to thank the mentors for their participation in this program: Walter Dunn, Ginger Gherardi, Les Jacobson, Jack Kay, Colin Rayman, and Tom Werner. Giving their valuable time to share their experiences and expertise is a wonderful gift. Special thanks go out to Les Jacobson and Ginger Gherardi for their personal mentorship and helpful guidance in the creation of this paper. The author also thanks Dr. Katherine Turnbull, Dr. Timothy Lomax, Mr. William Eisele Mr. Shawn Turner, and Ms. Pam Rowe for their invaluable help in this effort. Finally, special thanks to Dr. Conrad Dudek and Ms. Sandra Mantey whose hard work and dedication made this program possible.
The author acknowledges the following persons for the time which they contributed to this research effort:
Heidi Stamm of Pacific Rim Resources; Heidi Van Luven of the Maryland State Highway Administration; Robert Ritter of the Maryland State Highway Administration; Barbara Fischer of the New Jersey Department of Transportation; David Berg of the Washington State Department of Transportation; Joan Morris of the Virginia State Department of Transportation; Charlene Robey of the Virginia State Department of Transportation; and William Cannell of the Virginia State Department of Transportation.
A-33 REFERENCES
1. The Intermodal Surface Transportation Efficiency Act of 1991. Washington DC, 1991.
2. Turnbull, K. F. and J. W. Hanks, Jr., A Description of High-Occupancy Vehicle Facilities in North America. Report Number UMTA/TX-90/925-1, Texas Transportation Institute, College Station, TX, July 1990.
3. Olyai, K. and D. A. Skowronek, The East R.L. Thornton Freeway (IH 30) Movable Barrier Contraflow HOV Lane in Dallas, Texas: Evaluation of the First Two Years of Operation. ITE Compendium of Technical Papers, Vol, 64, Institute of Transportation Engineers, Dallas Texas, October 1994.
4. Fuhs, C., Operational Characteristics of Selected Freeway/Expressway HOV Facilities. January 1996.
5. Leman, C.K., P.L. Schiller and K. Pauly, Re-Thinking HOV Facilities and the Public Interest. Chesapeake Bay Foundation, Annapolis MD, 1993.
6. Telephone Interview with Heidi Stamm, Pacific Rim Resources.
7. Gard, J., P.P. Jovanis, V. Narasayya, and R. Kitamura, “Public Attitudes Toward Conversion of Mixed-Use Freeway Lanes to High-Occupancy-Vehicle Lanes,” Transportation Research Record 1446, Transportation Research Board, National Research Council, Washington DC, 1994, pp. 25-32.
8. Kim, S.G., J. Koehne, and F. Mannering, I-90 Lane Conversion Evaluation, Washington State Transportation Center, Seattle, WA, 1994.
9. Billheimer, J.W., J.B. Moore, and H. Stamm, High Occupancy Vehicle (HOV) Lane Marketing Manual. US Department of Transportation, Report # DOT-T-95-04, Washington, DC, 1994.
10. May, A.D., Screening Freeway Sections for Promising HOV Lane Candidate Sites. Transportation Research Board 75th Annual Meeting, Washington, DC, 1996.
11. JHK & Associates, Task 2.3, General Purpose To HOV Lane Conversion, Draft Task Report, HOV Pre-Design Studies, Puget Sound Region, Washington State Department of Transportation Office of Urban Mobility, April, 1995.
12. Stowers, J.R., “HOV Lessons from the Dulles Toll Road,” TR News 170, Transportation Research Board, National Research Council, Washington DC, Feb, 1992, pp. 5-9.
13. Telephone Interview with Joan Morris, Virginia Department of Transportation.
A-34 14. Telephone Interview with Charlene Robey, Virginia Department of Rail and Public Transportation.
15. Berg, D.B., L.N. Jacobson, and E.L. Jacobson, “Converting a General Purpose Lane to an HOV Lane: The Interstate 90 Project,” The 64th ITE Compendium of Technical Papers, Institute of Transportation Engineers, Dallas, TX, 1994, pp. 74-78.
16. Telephone Interview with David Berg, Washington State Department of Transportation.
17. WSDOT, “http://www.wsdot.wa.gov/regions/northwest/hovpage/hovmain.htm” World Wide Wed Page, August, 1996.
18. Fischer, B.L., “Lane Conversion Strategy for the I-80 High-Occupancy Vehicle Lanes in New Jersey,” The 7th National HOV Systems Conference, Los Angeles, CA, June, 1994.
19. Telephone Interview with Barbara Fischer, New Jersey Department of Transportation.
20. Telephone Interview with Heidi Van Luven, Maryland State Highway Administration.
21. Telephone Interview with Robert Ritter, Maryland State Highway Administration.
22. Maryland State Highway Administration, I-270 HOV Information Package, 1996.
23. The Sierra Club, Comments to “Take a Lane” Provisions in the Seattle Area Regional Transportation Plan, Seattle, WS, 1993.
A-35 APPENDIX
HOV CONVERSIONS INTERVIEW FORM
1. Agency:______
2. Contact Name:______
3. Contact Tel:______
4. Contact Fax:______
5. Contact E-Mail:______
6. Project Name:
7. Briefly Describe Project:
8. Was this project implemented and currently operating? Yes No Pending
9. What was the target audience(s) of your marketing campaign? How was this target audience(s) determined? At what stage was the target audience determined? What preliminary research was made into this target audience(s)?
10. What agencies where were involved with the planning and implementation of this project? What role did they play? At what stage in the process were they contacted and involved? Was support maintain through out the project?
11. At what stage was a public information campaign initiated? What information was included in your public information campaign? At what stage was this information distributed? What mediums were used to carry the information to the target audience(s)?
12. Was media, public, and political support maintained through initiation and operation of the project? What methods were used to gain/hold media, public and political support through the final stages of the project?
13. What were the biggest pluses and minuses of your conversion project?
14. Do you know of any other persons or organization I should contact in your area or nationwide with regards to HOV conversion projects?
A-36 Matthew E. Best received his B.S. in Civil Engineering with Distinction from the Pennsylvania State University in May 1995 and will receive his M.S. in Civil Engineering with emphasis on transportation from Texas A&M University in December, 1996. Matt is currently employed as a graduate research assistant at the Texas Transportation Institute. At Texas A&M University, he has been actively involved with the Student Chapter of the Institute of Transportation Engineers (Vice President, Chapter Photographer, Co-manager of new student program). Recent honors include reception of the Luther DeBerry Distinguished Researcher Fellowship and selection as the TexITE Outstanding Student of the Year. His interests lie the area of transportation planning, operations and design with special interest in corridor and public transportation planning.
A-37
ADDRESSING SECURITY ISSUES IN ITS/ATMS
by
Christopher L. Brehmer
Professional Mentors Jack L. Kay, P.E. JHK & Associates
and
Colin Rayman, P.E. Ontario Ministry of Transportation
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Dr. Conrad L. Dudek, PhD., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas
August 1996 SUMMARY
New technologies are being introduced to the transportation realm at a whirlwind pace. These technologies incorporate the latest achievements in Intelligent Transportation System (ITS) and Advanced Traffic Management System (ATMS) related fields and will serve to usher in a new generation of surface transportation. Surrounding the excitement of ITS and ATMS systems is a growing concern among some members of the transportation community that the security associated with these new technologies is insufficient. As these technologies are implemented, proper security precautions should be taken to protect the integrity of operating systems.
The objectives of this report were to create an awareness of security issues surrounding emerging ITS and ATMS technologies and to provide recommendations to address those issues. In order to determine the transportation industry’s security needs relating to ITS and ATMS technologies, an interview process was undertaken. Breaches of security involving field equipment, ATMS centers, and computer systems were identified through telephone interviews conducted with industry experts.
This paper presented the findings of the interview process as well as a discussion of recent security problems faced by other technology-based industries. In addition, a framework for developing security systems was offered. The historical breaches of security, in conjunction with the perceived risks surrounding ITS and ATMS technologies as identified by the interviewees and the author, were used to develop a list of recommended security measures. These recommendations set forth basic security measures that should be considered relative to ITS and ATMS technologies. Finally, a case study involving the development of a security system for a fictitious ATMS center was presented to illustrate the use of the security evaluation process and recommendations offered in this paper.
B-ii TABLE OF CONTENTS
INTRODUCTION ...... B-1 Background ...... B-1 Problem Statement ...... B-1 Objectives ...... B-1 Study Methodology ...... B-2 Task 1 - Identify Potential Security Risks and Their Implications ...... B-2 Task 2 - Develop Telephone Interview Questions ...... B-2 Task 3 - Conduct Telephone Interviews ...... B-2 Task 4 - Compile Interview Results ...... B-2 Task 5 - Identify Industry Weaknesses and Prepare Recommendations to Remedy ...... B-2 Task 6 - Apply Recommendations to a Fictitious ITS/ATMS Application .... B-2
INTERVIEW RESULTS ...... B-3 Introduction ...... B-3 Field Equipment ...... B-4 CMS Systems ...... B-4 Means of Communication ...... B-5 Vandalism of Field Equipment ...... B-7 Computer Controlled Signal Systems ...... B-7 ATMS Centers ...... B-8 Facility Access ...... B-8 Employee Safety ...... B-9 Interagency Operations ...... B-10 State-of-the-Art ATMS Centers, A Case Study ...... B-10 Computer Security ...... B-12 Currently Utilized Computer Security ...... B-12 Incidents Identified ...... B-13 Internet Web Sites ...... B-13 Prevailing Opinions - Is the System Secure? ...... B-14 Opinions on System Security ...... B-14 The Perceived Threats ...... B-14
DISCUSSION ...... B-15 Security Related Experiences of Other Technology-Based Industries ...... B-15 Potential Threats ...... B-15 The Future Security of ITS/ATMS Technologies ...... B-16
B-iii Development of a Security System: An Overview ...... B-17 Goals ...... B-17 Identify the Risks ...... B-17 Command Structure ...... B-17 Employee Considerations ...... B-17 Identification of Countermeasures ...... B-18 Selection of Countermeasures ...... B-18 Additional Considerations ...... B-18
IMPLEMENTATION RECOMMENDATIONS ...... B-20 Field Equipment ...... B-20 ATMS Centers ...... B-23 Computers ...... B-27
APPLYING SECURITY SYSTEM PRINCIPLES AND RECOMMENDATIONS: A CASE STUDY ...... B-30 Introduction ...... B-30 Establishing Goals and Identifying Risks ...... B-30 Command Structure ...... B-31 Employee Considerations ...... B-32 Identification of Countermeasures ...... B-32 Selection of Countermeasures ...... B-33 Implementation ...... B-34
CONCLUSIONS ...... B-35
ACKNOWLEDGMENTS ...... B-36
REFERENCES ...... B-37
APPENDIX ...... B-40
B-iv INTRODUCTION
Background
The continuing trend to incorporate advanced technologies into the nation’s transportation system through the application of Intelligent Transportation System (ITS) technologies is advancing at a rapid pace. Strong evidence of the progress being made can be seen in the proliferation of equipment ranging from field technologies such as changeable message signs (CMSs) to Advanced Traffic Management System (ATMS) centers that combine and centralize transportation operations through ITS technologies. Many of these advances have arisen due to the ever-increasing capabilities of computer and communication systems.
The introduction of modern computers and communication equipment has greatly increased the amount of data that can be collected and processed in order to manage the nation’s roadway systems and has resulted in the expansion of ATMS centers to incorporate interagency tasks as well as personnel. The emerging ITS technologies are providing much better command and control services while permitting for rapid reactions to changing roadway and traffic conditions. Interagency operations such as those surrounding police, fire, and transit dispatching can now be managed from the same room that traffic operations are controlled in (1). Unfortunately, these technologies, by their nature, also raise several potential security concerns.
Problem Statement
The information age has brought with its benefits the very real risk of sabotage. Unauthorized tampering with the communication systems and technology that surround the roadway transportation system has the potential to result in incidents ranging from the annoying or embarrassing to potentially life-threatening situations. The bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, exemplifies the potential for concerted terrorist activities against public facilities (2). Devices ranging from computer viruses to electromagnetic-pulse bombs that destroy electrical components have the potential to seriously damage the command and control systems that the transportation engineering community is increasingly relying on.
The current move toward advanced control technologies such as those incorporated into ITS and ATMS may not be adequately emphasizing and incorporating appropriate security measures. Given that the realm of transportation systems now includes not only transportation engineers but also computer, electrical, and communication specialists, it is vital that the importance of system security be emphasized and incorporated into all aspects of operations regardless of whom develops individual components.
Objectives
The objective of this paper was twofold. The first objective was to create an awareness of security issues surrounding ITS/ATMS technologies through the identification of previous security
B-1 breaches as well as potential threats. Having identified both historical and potential future problems, the second objective of this paper was to develop recommendations for enhancing system security.
Study Methodology
Task 1 - Identify Potential Security Risks and Their Implications
The purpose of this task was to brainstorm a list of potential security risks and the impacts that a breach of security might have. Several topic ideas were generated by the author with the support of mentors who were assisting in the graduate transportation engineering course that this paper was prepared for.
Task 2 - Develop Telephone Interview Questions
Given the ideas generated in Task 1, a telephone interview format was developed that sought information regarding three major topic areas. Those areas included past breaches of ITS/ATMS system security, perceived security risks, and countermeasures in place or under development. The appendix contains a list of the potential questions that were to be discussed during the telephone interviews.
Task 3 - Conduct Telephone Interviews
Having identified a list of questions to be asked of the interviewees, several relevant individuals identified by the mentors and the author were contacted by telephone.
Task 4 - Compile Interview Results
Results from the telephone interviews were categorized to reflect the major topics discussed by the interviewees and to provide focus to this paper.
Task 5 - Identify Industry Weaknesses and Prepare Recommendations to Remedy
Recommendations were made by the author to enhance system security based upon the security actions taken by the interviewees and their respective agencies, the identified historical breaches of security, and the perceived threats to system security and their potential impacts.
Task 6 - Apply Recommendations to a Fictitious ITS/ATMS Application
The process of developing a security system based on the recommendations made in this paper was illustrated. First, a methodology to develop security systems was offered based on literary references. That methodology was then used to develop a security system for a fictitious application of ITS/ATMS technologies. The recommendations developed in Task 5 were incorporated into this process.
B-2 INTERVIEW RESULTS
Introduction
The following paragraphs summarize the results of the telephone interview process. A total of 19 interviews were conducted that offered substantial information related to ITS and ATMS center security. Table 1 provides a summary of the broad spectrum of agencies represented by the interviewees.
Table 1. Listing of Agencies Represented in The Interview Process.
Agency Nature of Agency
AlliedSignal Inc., Transportation Systems & Services Private Consultant
Arizona Department of Transportation, Traffic Operations Center Public
BDM International, Inc. Private Consultant
Connecticut Department of Transportation Public
Houston TranStar Public
Illinois Department of Transportation Public
JHK & Associates Private Consultant
Ministry of Transportation of Ontario, Traffic Management Central Region Public Operation, Computer Control Systems Section
Minnesota Department of Transportation, Metro Division Traffic Management Public Center
New York State Department of Transportation, Traffic & Safety Region One Public
Roper and Associates, Inc. Private Consultant
San Antonio TransGuide Public
State Highway Administration, Maryland Department of Transportation Public
Texas Transportation Institute, Houston Office University, Research
The Municipality of Metropolitan Toronto, Transportation Department Public
TRW, Inc. Private Consultant
Ventura County Transportation Commission Public
Washington State Department of Transportation Public
Through the telephone interview process, several examples of situations were identified that suggested the need for consideration of security measures when implementing ITS technologies.
B-3 Past breaches of security ranged from the humorous to the malicious. The following paragraphs summarize some of the more dramatic examples of security breaches that were identified by the interviewees in three areas: field equipment, ATMS centers, and computer systems.
Field Equipment
Field equipment was determined to be vulnerable to security problems by the nature of its location. The interview process identified several incidents involving field equipment security problems. Table 2 summarizes the number of incidents reported by the interviewees.
Table 2. Summary of Number of Interviewees Reporting Incidents.
Nature of Incident Number of Incidents Reported Display of an unauthorized message on 3 changeable message signs (CMSs) Vandalism of field equipment 5
CMS Systems
Five of the six agencies that related field equipment security problems reported negative experiences with the operation of CMSs. Several years ago, one public entity experienced a great deal of embarrassment after a disgruntled employee programmed CMS installations to display an obscene message during periods when traffic volumes peaked (3). In another instance, a computer hacker was able to gain access to portable CMS systems and display a derogatory message concerning the governor. The affected signs were being used as a temporary measure while a permanent CMS system was installed. The hacker was able to access the control system supporting the temporary CMSs by telephone and manipulated the software protocol that protected them. Fortunately, the agency responsible for the signs was able to trace and apprehend the source of the messages through cooperation with the telephone company and law enforcement authorities (4).
The third reported unauthorized message display was traced to an innocent oversight involving a solar powered CMS. During a prolonged period without sunlight, the sign lost power. When power was restored, the controller reverted to displaying its programmed default which, unfortunately, contained an unauthorized message. An investigation into the matter revealed that the sign supplier had placed the message into the default logic to test the sign at the time of its manufacture and the message had never been updated (5).
The most commonly expressed fear involving CMS field equipment was that of having inappropriate messages displayed. Portable CMS applications were considered especially vulnerable by the interviewees. While the CMS installations discussed in the interviews relied on some form of computer software protocol to screen users, the interviewees acknowledged that the potential to tamper with CMS messages existed. One of the scenarios cited was that of a construction worker
B-4 or a disgruntled employee of the sign’s manufacturer (both of whom would be familiar with the software and its protocol through their experience using it) displaying obscene messages on a CMS.
The interviewees identified several means to insure that only officially approved messages were displayed. Two of the more popular items mentioned were spelling and grammar checkers built directly into the system. Two forms of such systems were identified by the interviewees. One simply would not recognize and display words outside a preset vocabulary while the other had preprogrammed words that it would not display, including the governor’s name (6, 7). A capability was also in use that permitted a supervisor to override the system and authorize messages that operators could not (8).
One agency reported the use of a dial-back confirmation system to restrict access even further. The CMS dial-back system was operated such that the CMS installation(s) required the location of the caller to be known. Essentially, the operator telephoned the sign and stated that “I am the operator at site Y.” The sign then called a preset number at site Y and, assuming the original call was authentic, relied on password privileges for the operator to authorize a new message (3). Four of the interviewees reported that dial-back communications with CMS installations were unnecessary as their agencies’ communications were, or soon would be, handled entirely by fiber optics.
Means of Communication
The interviewees cited communication systems as a vital consideration in determining the security of individual field components. Table 3 presents information regarding the types of communication equipment in use as identified by the various interviewees.
Table 3. Summary of Type of Field Communication Equipment Used.
Type of Communications Used Number of Number of Problems Interviewees Using Experienced Fiber Optic/Dedicated Telephone Lines 7 0 Cellular Phones 6* 1 Cellular Phone with Call-Back Feature** 2 1 *One interviewee’s agency was converting to fiber optic communications **Call-back feature permits use of cellular phone to both receive and transmit calls
As noted in Table 3, seven of the interviewees reported their agencies used fiber optic and/or dedicated telephone line communications to connect with permanent field installations. Dedicated lines to these systems were felt to greatly reduce the risk of both unintentional and intentional tampering. They were not, however, considered infallible. The possibility of communication lines being inadvertently spliced or severed was cited as a potential scenario that would interrupt operations. While dedicated communication systems were considered appropriate for permanent installations, portable sites often relied on cellular phones.
B-5 Concerns with communications to portable CMS equipment involving cellular phones were expressed by four of the interviewees. One interviewee reported that their agency had experienced security problems involving cellular telephone communications to its CMS installations during the spring of 1996. The agency had been operating eight CMS and two Highway Advisory Radio (HAR) portable trailers for construction applications. These units relied on cellular telephone technology to communicate with the appropriate control personnel and, in order to provide dependable service, the cellular phones on each piece of equipment were furnished with a call-back feature. The call- back feature was intended for diagnostic purposes and allowed a given field unit to place telephone calls to the center that controlled its operations. The operating concept of the call-back feature was that the field unit could alert the controller in the event of problems such as a depletion of solar power. In order to permit such operation, the trailer-mounted cellular phones were continuously activated. Unfortunately, the nature of cellular phones allowed this call-back feature to be exploited (5).
Cellular phones transmit a unique serial number identifying the customer when a call is made. Once that number is transmitted, it is authenticated and the desired connection is made. Unfortunately, devices that are capable of reading the unique identification number of a given cellular phone have been identified (9). In the case of the portable CMSs, such a device was used to identify two of the trailer-mounted cellular phones’ identification numbers. Those two numbers were then illegally sold by the individuals(s) that obtained them and reprogrammed into cellular telephones for personnel use. The individual(s) paying for the illegally obtained numbers were then able to make cellular phone calls that were billed to the agency operating the CMSs without ever affecting the CMSs or their messages. The telephone company that the agency operating the CMSs contracted with identified a sudden surge in the cellular phones’ usage and alerted the agency. Because of the nature of the situation, the agency was not billed for what eventually totaled nearly $1000 in unauthorized cellular phone calls (5).
In order to prevent the recurrence of such incidents, the situation was rectified by deactivating the call-back diagnostic feature that required the cellular phone on the field unit to be continuously transmitting. The cellular phones were converted to a receive-only status such that only one-way communications transmitting messages from the control center to the field installation were possible. In this manner, the cellular phones were only active for brief periods of time. This made it much more difficult for a potential criminal to hone in on each unit’s unique identification number. Continuous monitoring of the telephone bill attributed to a given unit (often automatically done by cellular phone companies) was also strongly recommended (5).
The four interviewees relying on cellular phones for communications with their CMS equipment noted that, even if the telephone number of the cellular phone on a given sign was obtained, the sign itself was still protected by software within the CMS unit. Each CMS unit was reported to have software protocol configured within the unit that required the user to know how to properly access and manipulate the system. The correct protocol had to be followed before any message could be altered or displayed. Because of this protective feature, it was the opinion of the interviewees that only someone who had experience with the software would be able to easily alter and display messages.
B-6 Vandalism of Field Equipment
According to three of the interviewees, vandalism of field equipment had negatively impacted ITS and ATMS system operations in the past. As was originally noted in Table 2, five incidents involving the vandalism of field equipment were reported.
The nature of the incidents reported varied widely. One agency reported that a CMS installation had been shot at and that three transmitters were stolen from its HAR sites. These incidents were reported to law enforcement officials and formal investigations were underway. In an attempt to address the problem of the stolen HAR transmitters, the agency involved installed more heavily reinforced field cabinets in areas where the threat of recurring problems was felt to be the greatest (10). Another interviewee noted that CMSs had been spray painted (11). Unfortunately, the random vandalism of equipment was considered to be virtually impossible to prevent unless the perpetrator was observed committing the crime.
All of the interviewees who offered knowledge on field cabinet installations reported that a minimum of lock and key security was in place. Limiting the number of access keys to field equipment was cited as a security technique (12). One of the interviewees noted the provision of intrusion alarms on field cabinets that alerted the control center if a cabinet door was opened (6). Another interviewee noted that such intrusion alarms were not necessarily useful because, even if an alarm reported a problem, the damage would likely already have been done (13).
One of the interviewees reported that their agency fitted its Closed Circuit Television (CCTV) field cameras with guard screens in an attempt to protect them. Apparently, soon after their initial installation, rocks were thrown at some of the CCTV cameras (11). In evaluating the need to protect CCTV installations, it was noted that consideration should be given to the local political climate. One of the interviewees reported that their agency, whose jurisdiction was known to host some militant anti-government groups, was very concerned about the impact of installing CCTV monitoring along portions of its roadways. Some of the wires running to the CCTV camera installations were, in fact, shot. Due to many people’s apparent impression that the government was spying on them, the operating agency arranged for the video images from the cameras to be made available to the news media and via the Internet on a controlled basis. Once the pictures were shown on the evening news, people apparently grew accustomed to them and most of the perceived apprehension concerning the installations was successfully diffused (14).
In general, the vandalism dilemma was considered to be site specific by the three persons who cited it. Given that the remainder of the persons interviewed reported no problems with their field equipment, it would appear that evaluation of localized measures would be appropriate.
Computer Controlled Signal Systems
Six of the interviewees reported the use of computer controlled traffic signal systems. The extent of computer control ranged from time-of-day operations to traffic-adaptive signal systems such as SCOOT (Split, Cycle, and Offset Optimization Technique). While most of the support equipment for such systems was housed in an ATMS center where it was reasonably secure, certain equipment had to be located in the field.
B-7 Locked and monitored field cabinets provided one avenue of protection against unauthorized access to this equipment. In addition to secure field cabinets, one agency located some of its field communications equipment (such as the remote multiplexors that were used to route information to and from individual controllers in their Main Traffic Signal System, or MTSS) at secure, limited access facilities that included police, ambulance, and fire stations (15).
As was the case with other applications, communication systems with the MTSS and SCOOT signal systems were made remotely accessible via dial-up modem to allow for field adjustments. A tiered password system was employed such that only certain individuals could actually affect the signal system’s operations. Privilege levels ranged from those who could only view signal timings to those who could add and/or drop intersections from control. An additional precaution taken to insure authorized use of the dial-up feature involved the disconnection of the modems during periods when no field work was scheduled. Routine backups of the computer operating systems were also made at the control center and stored both there and off-site in the event that the system was corrupted (15).
It was noted that, even if computer controlled signal systems were broken into, malfunction management units (formerly known as conflict monitors) in the controllers of individual signals would prevent anyone from displaying conflicting signal indications. For example, all of the movements of an intersection could not be given a green light simultaneously without physically accessing a signal’s controller unit at the intersection. As a result, while a signal network could potentially be used to create gridlock by changing to inappropriate timing plans, no accidents would be caused by the display of conflicting signal indications (16).
ATMS Centers
The telephone interview process also identified security issues and problems that ATMS centers had experienced. The operations of 11 ATMS centers were discussed during the interview process. Of those 11 centers, six were strictly concerned with traffic operations while the other five centers incorporated multiple agencies such as police and transit operations. In general, it was found that security was recognized as an essential component of these facilities. Newly constructed facilities were found to have incorporated higher levels of security than their predecessors.
Facility Access
Two of the interviewees reported that their ATMS centers relied on lock and key entry to the building and that, once access was gained, no other limitations on movement within the building were in use. Both of these facilities functioned exclusively as traffic operations centers. The remainder of the facilities used swipe cards for building access. The swipe cards essentially acted as a high-tech key system. Each swipe card had a magnetic strip (similar to those found on credit cards) that was coded with certain access privileges consistent with the card holder. The card then was used much like a key; an electronic reader device was located at each locked access point and unlocked those doors that the card’s coding permitted.
The interviewees identified several other facility security measures including CCTV monitoring, motion detection systems, external loudspeakers, fencing, mechanical gates, coded entry
B-8 points, and other perimeter surveillance systems. While each of these devices had inherent security advantages and disadvantages, it was noted that they also attracted attention to the facility. High barbed wire fences and other obvious measures were felt to attract undue attention to facilities thereby making security an even larger problem by publicizing the existence of what previously had been an undistinguished building (8). The location of trees, buildings, and other site obstructions were also noted to have restricted the abilities of techniques such as CCTV camera monitoring. The existence of multiple obstructions required additional CCTV cameras to effectively monitor an entire facility, thereby making the equipment even more conspicuous.
In addition to discussing security access measures, three of the interviewees reported breaches of ATMS center security. While not recent in nature, theft problems that were attributed to an ATMS center’s janitorial service were noted (12). One ATMS center discovered that a contracted janitorial service provider had hosted a beer party in the control center (17). In another case, an individual simply appeared within the terminal building of an ATMS center. While no damage was done, several operators were quite surprised as access to the building was controlled. The security system in place at the time required that individuals be “buzzed in” through an electromagnetically locked door. An investigation into the incident concluded that an employee must have accidentally allowed the perpetrator to slip in as they were exiting (17).
One of the more humorous stories relayed through the telephone interviews took place approximately 20 years ago. At that time, the agency involved leased the second floor of an office building to house its traffic control center. While the agency was aware that the facility’s owners on the first floor had access to the center, they were not aware that the owners had been using their office on weekends until the owners invited some of the agency’s employees to the movie theater. It was soon discovered that the facility owners had been making a low budget “spy movie” and had used the traffic control room as a movie stage for “CIA” headquarters. A map of the world used by the agency to denote the origins of visitors to the center had been used as a depiction of the locations of “field agents.” While the movie never gained popularity in the U.S., it was apparently widely distributed in Greece. The interviewee, while noting the humor of this situation, cited ownership of the facility that houses a given ATMS center as a distinct advantage (17).
Employee Safety
Concern for the physical safety of employees of ATMS centers was expressed by one of the interviewees. Their agency’s ATMS center was located in a high crime area of a major city. At this site, ATMS center employees’ vehicles had been broken into, there had been verbal assaults, and spent ammunition rounds had been found near the facility (though they were not necessarily directed at the center). Staffing levels, which were expanded to encompass 24-hour operation, also represented a concern. Operation of night shifts staffed by two and three persons (sometimes all female) lead to anxiety among some employees (14). Another control center, located along an expressway, noted that motorists occasionally had tried obtaining assistance after suffering vehicular failures. In this instance, people simply walked up to the entrance of the ATMS center and knocked for help (17). These concerns may not have appeared to directly impact the ATMS centers’ operations; however, the morale of the employees would be expected to affect their job performance. Furthermore, it was noted that security systems benefitted from a low staff turnover rate within an organization (13).
B-9 Interagency Operations
Five of the 11 ATMS centers represented through the interview process incorporated multiple agencies such as police and transit operations. Three of these interagency operations had at least a partial separation among the agencies. Those three operations reported independent communication systems were in use that could only be linked by select persons during appropriate instances such as regional incident management. Those same centers reported very strict access control to the floor of the actual control center.
In general, it would seem that the ATMS centers that incorporated multiple agencies had much more advanced security systems. While two of the agencies that held strictly traffic management duties reported simple lock and key entry to their center, multiple agency operations typically incorporated several layers of security with a progressively smaller group of personnel having access at the upper control levels. This trend in facility security was attributed to the fact that an awareness of the need to address security issues had become much more widely accepted in recent years as opposed to the perceptions of 20 and 30 years ago. In addition, operations that incorporated entities such as local and state police inherently had additional security measures in place. For example, uninterruptible power supply (UPS) systems, which were not considered an absolute necessity for traffic management, were a fundamental requirement for police dispatching operations (18).
One of the new ATMS centers that incorporated interagency operations was brought on line during the winter of 1995-1996. Nature’s harsh realities served as a baptism for its operations and essentially forced interagency cooperation. Within this control center, operators on the control floor all held the same access privileges and no significant barriers (such as electronic firewalls) between interagency operations were in use. While this center’s operations were not fully integrated at the time of the interview, its success at developing a truly cooperative atmosphere mirrored that of others (4).
State-of-the-Art ATMS Centers, A Case Study
While the previously cited incidents raised potential concerns regarding the security of ATMS centers, it should be noted that only three of the 11 centers identified by the interviewees reported problems. The remainder of the interviewees indicated that extensive security measures were in place at their facilities. The following paragraphs highlight security measures taken at two new, state-of-the-art ATMS centers.
The new TransGuide Center in San Antonio, Texas, offered a glimpse of future trends in ATMS center development. Commissioned in July of 1995, this facility incorporated police dispatching, transit, and traffic management into one building. Within TransGuide, there was also an alternate emergency management center for the police.
The TransGuide building itself was protected by contracted security forces, 24-hour CCTV monitoring, and a coded exterior entry system that activated after hours. Interestingly, the facility had no exterior fence as the designers did not want to create an obvious target. Within the facility, there was a revolving “man trap” door controlled by the security forces that allowed only one person
B-10 through at a time (much like a turnstile). In addition, coded entry points were located at doors leading to the lobby, computer room, and control center. As a supplement to the guarded entry system, all personnel wore identification tags (8).
The center was also equipped with an UPS system capable of continuously supporting operations during times of crises. Double walled steel field cabinets were installed to prevent unauthorized access to field equipment. Whenever a cabinet was opened, a message indicating such action was automatically relayed to the ATMS center operators (8).
Communications from TransGuide were handled through various means, with the center boasting its own dedicated communications network. All communications were conducted via fiber optic technology with the police having a separate fiber optic network. Because of the fiber optic networks, TransGuide’s communication system did not have external electronic connections and so could only be accessed by an external computer if a manual connection was made within TransGuide. With no external links providing potential access points to the communications system, there had not been any problems experienced with computer hackers. TransGuide did provide a separate news media site which selected news media were allowed to access remotely. This eliminated the need to accommodate reporters within the TransGuide building (8).
Multiple levels of computer entry passwords were established within TransGuide in order to create a hierarchy of system control. Within this hierarchy, certain people were assigned specific levels they were permitted to access. These levels reflected a command and control structure established among the operating personnel to prevent unauthorized persons from accidentally impacting operations. For example, only the floor manager could authorize changing CMS display messages (8). In addition, logs were kept of all operators’ activities. These logs included a record of the time that all commands were sent and the time that those commands were actually executed by a given operator. Access to the log was limited to select individuals and all actions taken were automatically printed on the supervisor’s console printer so that the supervisor was constantly aware of changing events (6).
The new ATMS center in Atlanta, Georgia, also incorporated several security conscious concepts into the facility. Atlanta’s system had been on-line for approximately two months at the time of the telephone interview and was still under construction but several noteworthy aspects of its design were discussed. The system itself operated in a dispersed manner with eight agencies relying on a distributed client/server computer system. For operational purposes, each agency had its own jurisdiction and database that could be linked with other agencies’ software if a given individual had appropriate access privileges. Interagency firewalls were established such that the traffic management personnel could not support police enforcement of speeding and ticketing, but could help with other law enforcement operations. For example, while the traffic management personnel normally controlled the CCTV installations, that control capability could be made available to other appropriate personnel for regional incident management purposes. There were also physical and software limitations placed on the CCTV cameras so that they were not used improperly (Designers wished to eliminate the possibility of personnel spying on apartments, attractive persons, etc.) (19).
B-11 Like the TransGuide Center, the Atlanta facility was preemptive in terms of external computer attacks; all outside sources were locked out. All communications with field equipment were made through fiber optic means. In order to internally protect the computer system at the center, a rigorous software tiering system was adopted that incorporated many defense department software policies. As the interviewee stated, you “don’t have to be green to use it” (19).
Because the building housing the Atlanta ATMS center would eventually host multiple agencies (but not all in the control room), a system using layered access by privilege levels coded on swipe cards was in use. The center’s management was very cautious about who received access to the various operating systems. Employees were subject to extensive training programs as well as levels of responsibility and development as they advanced their privilege level. As with most employers, the security system was reactive in terms of potential disgruntled employees; such persons weren’t denied access until they demonstrated negative performance (19).
Computer Security
Computers have been an integral component of the development and implementation of ITS and ATMS center technologies (1). The degree of computer security reported by the interviewees ranged from reliance on basic password protection to the use of carefully tiered privilege levels.
Currently Utilized Computer Security
One area where interagency access and unauthorized outside access were still viewed as a potential problem by those interviewed rested in computers. As noted by one of the interviewees, interagency computer systems had the potential to fail when people who didn’t have the authority or expertise to do what they were doing inadvertently caused an incident (3). The possibility of such accidental incidents increased exponentially with the ease of executing commands through today’s computer driven operations. The interviewees all felt that access privileges to computers should consider the needs of all participating agencies. At the same time, a reasonable system of protection was considered necessary to avoid both accidental and intentional computer tampering.
The potential for outside interference or tampering with operations via computer was recognized by the interviewees. Three of the interviewees reported the use of dedicated computer systems that were not subject to outside connections. All the interviewees who discussed computer systems related that at least some level of firewall protection was in use. Firewalls were described as an electronic perimeter defense system placed at access points between computer connections within a given computer network.
All of the interviewees reported that tiered computer systems were in use for protective purposes. For example, one ATMS center relied on a system with embedded security at three levels. Entry to the center’s computers first had to be gained through the operating system. A second layer of password protection was then located at the entrance to the application level. Finally, within a given application, (CMSs, ramp metering, etc.) an additional layer of security was in place so that the control aspects could only be modified by designated terminals within the control center (13).
B-12 The agencies that relied on dial-up communications also had incorporated security measures into their operating systems. Dial-up communications allowed a remote computer user to access another computer system via a telephone modem. These were noted to be especially popular in making field adjustments to computer controlled traffic signal systems. One dial-up modem system discussed was designed such that the user dialed in the system’s number and received only a tone in response. No further connection could be made until the user entered the correct password. The user then had to comply with additional protocol measures before being able to affect the system that they were working with. In addition, the dial-up system utilized a three-strike policy by which, if the correct identification process had not been followed, the port providing access to the computer system shut down automatically (3).
Incidents Identified
During the interview process, no historical breaches of security through computer hacking or viruses were identified. The interviewees did note that there had been incidents involving innocent internal tampering and/or accidental deletion. One incident, which didn’t affect field operations, resulted in an accidental lock-down of a computer system after an operator entered a software area that they were not qualified to be in (4). Physical access to computers was identified as a concern at one of the ATMS centers. In that instance, critical computer components that serviced the facility were located in highly accessible areas. Efforts were underway to relocate the machines to a more secure area (12).
Internet Web Sites
Six of the interviewees reported that their respective agencies had developed Internet Web Sites. The Web Sites typically offered real-time traffic condition information via Internet connections. Security concerns had arisen in developing these Web Sites because Internet connections typically represented a two-way link. Two-way Internet links were likened to a telephone line; data could be transferred from the Web Site to a viewer and vice-versa. The transfer of information by two-way links provided the potential for computer hackers to manipulate the Web Site and gain access to the Web Site provider’s computers. In the case of one newly commissioned ATMS center, there was a great deal of concern as to whether real-time Automatic Vehicle Identification (AVI) data that were fed to a local university and placed directly on the Internet might provide an unguarded entry point to the control center’s computers. In order to rectify the situation before an incident occurred, a custom-designed one-way data channel from the control center to the university was installed to transmit the AVI data (20).
While no major problems have been experienced with such Internet sites being used as access points yet, one of the interviewees reported that they had detected individuals probing their Internet connection. In that instance, the Web Site Director at an ATMS center detected an outside user exploring the connection’s firewall. The individual was caught by tracking his/her Internet Protocol (IP) address. An IP address was explained to be a logical address for a host connected to a network and could be traced to its origin much like a phone number. Further communications with that person were denied. While that perpetrator was caught, the point was made that major corporations use their own software firewalls that could potentially appear to be an attack on the ATMS center’s firewall. As a result, the ATMS center always sent E-mail to identified perpetrators to notify them
B-13 that their presence had been noted and to insure that the center wouldn’t be denying further access to a legitimate web browser (14).
In another instance, a transportation agency’s Web Site was affected by an indirect attack. The agency’s Web Site, which offered transit, traffic, and other related information to Internet users, was effectively erased from the Internet for a brief period in 1996. This occurred after the computers belonging to a separate Internet provider (who maintained the Web Site for the transportation agency) were sabotaged by a competitor. Backup computer files were eventually used to restore the Web Site (21).
Prevailing Opinions - Is the System Secure?
When one reviews the overall security needs of a given ITS/ATMS application, it is important to remain objective. Several additional points made by the interviewees provided a basis for consideration.
Opinions on System Security
The general perception of the interviewees was that all the security issues that could be reasonably addressed had been. Two of the interviewees noted that security reevaluations and upgrades were in progress and one noted additional facility security measures that could have been enhanced if the personnel and financial resources were available.
The Perceived Threats
The ten interviewees who discussed perceived threats to ITS and ATMS systems all felt that the largest threat to system security revolved around their own employees. Two scenarios were consistently cited. The first involved an employee accidentally causing an incident by either entering a computer application area they weren’t qualified to be in or by simply making a mistake. The second scenario involved a disgruntled employee taking actions that would negatively impact operations.
The same ten interviewees cited a lack of any major externally oriented security effort. They justified this position with statements echoing a theme that there were more attractive targets for computer hackers, terrorists, and other persons who desired to harm operations or make a statement. The opinion related was that there simply was no net intrinsic value of the operations and data currently handled by most ITS technologies and ATMS centers. Unlike the stock market or banks, there was no perceived benefit to gain upon entering. Two of the interviewees did, however, note that the coming of age of electronic tolling, automated enforcement, and precision tracking of police and transit vehicles would result in a continued development of databases with greater intrinsic values (3, 6).
In general, while a need for some security was agreed upon, the fiscal reality of most operating agencies’ budgets precluded guarding against anything except the most probable threats. Furthermore, many of the public’s perceived security risks were attributed to paranoia and it was stated that more security would only lead to less flexibility.
B-14 DISCUSSION
The incidents identified in the previous section of this paper highlight the need for some degree of security at all levels of ITS and ATMS technology applications. The lack of major incidents being identified through the interview process, coupled with the comments of the interviewees, suggests that security issues have generally been adequately addressed. However, as two of the interviewees pointed out, the coming of age of electronic tolling, automated enforcement, precision tracking of police and transit vehicles, and other technologies will result in the continued development of databases with increasing intrinsic value.
It is the opinion of the author that potential threats to ITS and ATMS center security are greater than those reflected by the interview results. There is certainly a great deal of merit to the statements made by the interviewees and their thoughts are not to be discounted. However, statements made off the record by individuals who requested not to be referenced in this report suggest that incidents have already happened and are simply not being publicized. A brief review of recent literature is thus offered to illustrate some of the problems and concerns that have been experienced and reported by other technology-based industries.
Security Related Experiences of Other Technology-Based Industries
Potential Threats
A recently published article offers a glimpse of fears the defense community has for the nation’s information systems. According to the article, “Outside the military, the National Security Agency is deeply worried that computers controlling banking, stock exchanges, air-traffic control, phones, and electric power would be easily crippled by determined hackers.” The article further notes that “hackers may be the new mercenaries, available to the highest bidder” (22). More than 30 countries are known to have sponsored efforts in attacking and protecting information systems, including the United States (23). While these ideas may seem extreme, the attack on the World Trade Center in New York and those on other financial institution facilities in London are cited as early examples of information terrorism (23).
There are threats beyond those associated with foreign countries and terrorists. In 1994, computer hackers were able to infiltrate computers connected to the Internet at General Electric Co. The hackers were able to gain access to research and proprietary information on computers in two cities after breaching the system’s “robust” firewalls. In addition, the hackers were apparently able to obtain passwords of employees that allowed them to connect to more than a dozen other Internet computers including at least one other business and several universities. It was noted that few incidents of such a nature are publicly reported because companies fear embarrassment and do not want to further compromise security by releasing information that could be used by hackers (24). In a separate incident that occurred in 1993, one of the Federal Aviation Administration’s weather computer systems failed for 12 hours after a time-activated logic bomb was detonated (23). Logic bombs are a type of computer virus that remain dormant in a system until a predetermined release time (22).
B-15 An awareness of the ease of obtaining passwords is also noteworthy. Listening devices, often in the form of sniffer programs, can be introduced into networked computers. These programs, many of which have been found on the Internet, are capable of observing and recording communications between computers as well introducing forgeries or Trojan horses into systems. A Trojan horse, as described in Securing Client/Server Computer Networks, essentially is a program that captures the login name and password of a given computer user. The program can be written to activate when a user turns on their computer and can be removed at the command of its creator (25). Here again, realization by employees of the need for computer access control and protection is essential. There is no need for Trojan horses or similar devices to obtain passwords if employees use easily guessed passwords such as their name and/or do not routinely change their password. Employees who leave a note on their desktop with their password written down because they have trouble remembering it also provide easy access for would-be perpetrators. There are of course, tradeoffs to using complex password levels; anyone who has to log in through multiple layers can relate to the frustration of having to do so daily (25).
Other weapons of the “information war” that currently exist include non-nuclear electromagnetic-pulse (EMP) bombs and Van Eck bugging. EMP bombs generate a high-energy electromagnetic pulse that has the capability of burning out all electronic components in a building. The detonation of such a device, (which the Los Alamos National Laboratory in New Mexico has now refined to be suitcase-size) could literally eliminate a building’s information processing capabilities (22). By comparison, Van Eck bugging is a non-destructive technique that allows video displays within buildings to be monitored from a distance. Such technology was used by a British television station to demonstrate that Scotland Yard’s computers could be observed from outside of the building (23). Similar technologies can be used to extract data from computer systems via emanations conducted through power lines. According to one source, “For a cost of a few hundred dollars, anyone with the desire and knowledge to do so can observe information on your video terminals in real-time, thus leaking information as it is created or used and gaining detailed knowledge of how it is used and by whom” (23).
The Future Security of ITS/ATMS Technologies
These literary references highlight a few of the potential threats that could be encountered by ITS and ATMS technologies. They are presented to create an awareness of the concerns any industry dealing with information technology will face in the future. The author of this paper concurs with the interviewees’ assessment that it is unreasonable to attempt to protect ITS and ATMS technologies against such threats at this time. In all likelihood, the targets of such exotic attacks will have higher intrinsic values than ITS and ATMS technologies. The concern of the author then, is that the future development of information technologies in the transportation field could render ITS and ATMS systems targets. Consider the consequences of persons using technology such as Van Eck bugging to spy on ATMS centers and observe the exact location of all police equipment in operation. Provision of such information to the wrong person(s) could prove disastrous. As noted by two of the interviewees, automated law enforcement and electronic tolling will likely create targets within ITS and ATMS centers that have immense financial value. It is therefore appropriate that, as ITS and ATMS technologies are expanded, care is taken to provide security commensurate with the value of those systems (3, 6).
B-16 Development of a Security System: An Overview
In order to objectively evaluate ITS and ATMS technology security needs, an unbiased evaluation methodology should be used. The following is a review of the key points involved in the development and implementation of a security system as identified by the various literary references cited. The purpose of this section is to provide a generic framework from which the remainder of this paper can be developed.
Goals
Like any other planning process, the first step in developing a security policy is defining what the purpose and goals of the system will be. Depending on the location and nature of the operation, security policies as well as the systems that reflect those policies will have to be specialized. The development, installation, and daily operation of security systems can have a profound impact on the lives and productivity of employees. Security and flexibility often are considered to be inversely related; the more security that is built into a system, the less flexible that system is. As a result, the level of sophistication applied in both the planning and implementation of security is crucial to a security system’s success. As noted by Olnes, when one focuses on a random approach to providing security, “one runs the risk of introducing countermeasures that can be likened to a fireproof door in a wooden wall - expensive and with little or no effect” (26).
Identify the Risks
Inherent within the process of establishing goals is the need to identify risks. Realistically, the security of a given system can never be guaranteed and, in times of dwindling financial resources, it is impractical to attempt to provide for every eventuality. It has been suggested that listing the probability and consequences of a given security breach may prove valuable in establishing goals. This list of scenarios could also be broken into categories such as those that are accidental versus intentional and those caused internally versus externally. When evaluating the impact of an incident, consideration should also be given to the relative visibility and potential repercussions of the incident (26).
Command Structure
During the policy development stages, it is vital that a control hierarchy be established. The goals of a security policy must consider how the hierarchy of the system will function. In order for operations to be effective, an ultimate authority and a supporting chain of command must be enacted. Delegation of task responsibility must be established and a manner of access control must be instituted. Access control must differentiate between information and resources that should be provided to everyone versus what critical elements should have only limited access.
Employee Considerations
While the need for security measures is well recognized, it is also important to reflect on administrative measures. It is generally accepted that for most enterprises, the employees represent the largest threat to security. Employees must be encouraged to seriously consider the security
B-17 implications of their actions. By the same token, management must recognize the need to make security measures as user friendly for employees as is reasonably possible. Olnes notes that “The importance of a security conscious and motivated staff cannot be overemphasized. People simply will not accept restrictions in their daily work unless they see that the restrictions are sensible and necessary”(26).
Most employers rely on a tiered system of promotion and responsibility that should theoretically place only qualified persons in positions. Appropriate training and experience should be associated with every position within a given employment structure. At the same time, Olnes notes that “It is a paradox that even computer systems with high security requirements require maintenance staffs that are given full privileges to system and data, including data to which they should normally have no access whatsoever” (26).
Identification of Countermeasures
Having identified security goals, the next major phase of developing a security system involves selection of appropriate countermeasures. Three major categories of countermeasures have been identified. They include preventative, limiting, and correcting measures. As implied by their respective names, preventative measures are intended to prevent the occurrence of security breaches; limiting measures are structured to detect and limit exposure to occurring incidents; and correcting measures rectify any damage done. Within each category of countermeasures, there are three additional types of countermeasures. These include physical, logical, and administrative measures. Physical measures relate to the physical security of the given facility or equipment. Logical measures are used to control access to computers, while administrative measures involve everyday work procedures and employee conduct (26).
Selection of Countermeasures
Once the goals and criteria of a security policy have been established, the next component of defining the security system is to determine exactly what countermeasures will be put in place. Like any other evaluation process, a benefit/cost analysis can be used to select countermeasures. In some applications, a great deal of security will automatically be required for the system. In other cases, the task of evaluating what measures are necessary can be more difficult.
Beyond providing protection, it should be noted that security systems serve other purposes. For example, video-based security systems can reduce facility owner’s liability in lawsuits and assist in criminal investigations by providing a source of documentation of incidents that have occurred (27). The value of these additional services should be considered in the benefit/cost analysis. Risk evaluation and past experience will play a vital role in the evaluation process. It is also suggested that, having completed the benefit/cost analysis, all remaining risks be reevaluated to insure that appropriate measures have been selected (26).
Additional Considerations
Similar to any other process of this magnitude, documentation of the decisions made and the rationale for them is essential to successful long term operations. As risks change, obsolete
B-18 equipment is replaced, and new potential threats are identified, it is necessary to have concurrent modifications to the security system and policy. Staffing changes also should be carefully monitored and appropriate changes made in system security. Periodic disaster training and/or practice should be considered. While the thought of “security drills” for sabotage, theft, or intrusion may seem humorous to some, “if the defense against such threats is based on improvisation when the event occurs, one runs the risk of a real disaster” (26).
B-19 IMPLEMENTATION RECOMMENDATIONS
The comments of the interviewees, the methods by which they dealt with historical security breaches, as well as previously cited literary references, offer the basis for several recommended security considerations. The following paragraphs summarize suggested security considerations surrounding field equipment, ATMS centers, and computers. The recommendations that are presented were developed by the author using the methodology described in the previous section of this paper. For each of the three areas discussed, a tabular format was developed to illustrate the ITS/ATMS technology considered, potential threats, and recommended countermeasures.
The recommendations made should be regarded as basic guidelines to consider. Each ITS and ATMS technology application will have unique risks and security concerns associated with it. The personnel who are responsible for the implementation of that technology must consider their own unique situation in evaluating the appropriateness of security measures. Care should be taken to assure that the focus of security measures is appropriate. The benefits and cost of each security component will have to be objectively weighed with overall goals and then reconciled with fiscal reality. As noted earlier, the entire decision making process should be thoroughly documented for future reference. Finally, the importance of continuously reevaluating system security must be stressed.
Field Equipment
In many instances, field equipment may be the most vulnerable component of ITS/ATMS technologies simply because it is often remotely located. Conversations with the telephone interviewees who had previously experienced problems associated with field equipment highlighted several aspects of security issues and countermeasures that suited them.
One of the greatest challenges in evaluating security for field equipment will be determining what local concerns are. Each security application will be unique depending on the equipment’s location and value, environmental conditions, and past experience. Table 4 provides several recommended considerations for field equipment security.
B-20 Measures Administrative Security Administrative *Develop and document and document *Develop command and control including: structure 1) Ultimate authority 2) Hierarchy of access team response 3) Incident and maintain *Establish messages approved default within software as protocol/passwords *Change access gain/lose employees privileges *Seek employee recommendations *Insure that cellular provider provider cellular that *Insure monitors billing for abnormalities and document *Develop to process response incident address potential failures party responsible that *Insure number and exact knows nature of all connection points to system. made to all changes *Record and equipment policy both exact location of all *Record communication lines, underground those especially in place is that a system *Insure lines designate properly to or other coding (by color means) *Implement tiered software *Implement tiered software protocol incorporate should *Protocol firewalls to prevent hacking and/ spelling, vocabulary, *Use or grammar check software *Provide capability for to override supervisor protective features of dial-back use *Consider feature that logs software *Consider made and record changes of changes origin *Implement tiered software *Implement tiered software systems protocol to access and monitor to software *Use users well as as log all use Physical Security MeasuresPhysical Security Measures Logical *Provide mechanism to lock *Provide mechanism equipment *Locate equipment in area where conspicuous be likely would perpetrator by others observed if structure physical *Reinforce necessary wiring direct use *If possible, optic) fiber (i.e. connections *Eliminate call-back diagnostic diagnostic call-back *Eliminate cell-phone requiring feature continuously- transmit to convert to receive-only status communications *If two-way basis, on periodic necessary activate only when in use and keep transmission minimal period dedicated to points *Access be minimized. should lines redundancy into *Incorporate true that (recognize system redundancy requires in separate lines separate locations) separate at conduits and above- tape marking *Use designate to ground signs of underground lines location Table 4. Recommended Security Measures for Field Equipment Applications. Potential Threats In order of decreasing threat) ( *Employee mistake/innocent *Employee mistake/innocent oversight employee *Disgruntled hackers *Computer *Cellular phone numbers phone numbers *Cellular illegally obtained/cloned *Dedicated communication line accidentally severed or spliced Systems
Technology Field Equipment CMS Means of Means Communication
B-21 trative Security Measures *Develop and document and a response areas problem potential to address process failures local with and cooperate *Notify law enforcement in the event of vandalism-routine may be possible patrolling *If there are local political who are against activists work equipment, of certain use to educate the public on and use purpose equipment’s of number and type the *Limit equipment that can access keys notify alarms, intrusion *If using controller when equipment will staff be opened by authorized *Develop and document command and control including: structure 1) Ultimate authority 2) Hierarchy of access team response 3) Incident as protocol/passwords *Change access gain/lose employees privileges that information be *Insist routinely backed-up back-up power test *Routinely supplies *Implement tiered software software tiered *Implement protocol incorporate should *Protocol to prevent firewalls hacking for modem *Port shut should connections down automatically after three unsuccessful attempts to enter system of encryption use *Consider equipment Table 4. Continued. Physical Security MeasuresPhysical Security Measures Logical Adminis *Secure all equipment with locks *Locate equipment in area where conspicuous be likely would perpetrator by others observed locate possible, *Where equipment in police, fire, and offer that offices government more security installations, field *Reinforce steel double-walled consider etc. guard screens, cabinets, with equipment field *Furnish where alarms intrusion appropriate equipment making *Avoid attractive to vandals need to be serviceable *Recognize *Use dedicated communication communication dedicated *Use lines when modems field *Lock-out not in use back-up computer *Routinely at control and store software site and a separate location are that field cabinets *Insure secured locate critical possible, *Where fire, police, in equipment relay that offices and government offer more security Potential Threats In order of decreasing threat) ( *Political Activists *Others *Operator error *Operator hackers *Computer Technology Field Equipment Vandalism *Adolescents Computerized Traffic Signal Systems
B-22 ATMS Centers
Security surrounding ATMS centers largely depends on the nature of the center and its objectives. Because of the vast differences in the purpose and capabilities of these centers, the appropriate levels of security to protect them vary widely, as do the perceptions of risks to them. Many of the original ATMS centers around the country were developed strictly as a traffic control measure and, as such, their operators did not see any particular threats to the facility. This stemmed from a perception that there would be little intrinsic value in attempting to attack or otherwise break into such a facility. In contrast, many of the facilities currently being brought on-line incorporate police, transit, emergency management, and traffic operations. These facilities are perceived to represent a much more likely target for computer hackers, theft of data, and even potential terrorist activities.
There are several generic security measures that can be taken to limit physical access to facilities (27, 28). A recent article in an architectural magazine notes that “effective security is an interplay of three elements: natural and architectural barriers, including anything from landscaping strategies that discourage access, to the number, location, size, and type of doors and windows; human security, including the protection provided by guards and other personnel; and electronic security, provided by any one of the array of systems now available” (27).
Obviously, location of the facility will play a central role in determining what security measures are appropriate. Here again, the needs of staff should be considered in selecting what countermeasures are employed (27). Communication systems, power supplies, access points, physical integrity of the building, and several other issues are all directly affected by security considerations. In addition, building codes regarding access and egress during emergencies such as fires effect what countermeasures can be used. Yet another layer of regulatory codes is associated with the Americans with Disabilities Act which can affect aspects ranging from physical security barriers to systems which must accommodate both the blind and deaf (27). Security systems also must be designed such that they are not overly obtrusive, intrusive, or otherwise intimidating to employees.
A major concept of ITS technology is that it provides the right information to the right people at the right time. In order to fulfill that directive, many of the next generation ITS systems that are now being developed incorporate the concept of interagency cooperation. Within such an atmosphere of mutual cooperation, there is often still a need for some degree of separation of agencies and tasks. Realistically, in order to fulfill the concept of ATMS Centers, there has to be a spirit of cooperation and mutual trust between agencies. With the right management and personnel in place, the need for security may be of lesser value than the need for the flexibility of access to various system control components. Table 5 incorporates these concepts into recommended security features of ATMS centers.
B-23 Measures Administrative Security Administrative *Provide proper training to to proper training *Provide should employees-position with be commensurate knowledge and document *Develop command and control including: structure 1) Ultimate authority 2) Hierarchy of access team response 3) Incident of importance *Emphasize to employees security *Hire reputable service with (Beginning providers to and continuing janitorial who have access all persons to the center.) *Seek employee recommendations and extent media access *News be should of access prearranged *Software protocol should be in be in should protocol *Software access place to limit system system password *Basic would system password *Tiered be desirable *See additional computer recommendations, security Table 6 Physical Security MeasuresPhysical Security Measures Logical *Minimum of lock and key of lock *Minimum entry system *Ownership of facility desirable *Try to maintain low-key or other - no fencing presence undue attract that measures attention of camera monitoring *CCTV would be desirable access tags identification *Personnel desirable area for *Provide a secure critical computer/communication components Table 5. Recommended Security Measures for ATMS Centers. Potential Threats In order of decreasing threat) ( *Employee mistake/innocent *Employee mistake/innocent oversight employee *Disgruntled hackers *Computer Issues ATMS Center ATMS Basic ATMS center facility access
B-24 Measures Administrative Security Administrative *Security consultant should be should consultant *Security utilized to proper training *Provide should employees-position with be commensurate knowledge be should provided *Access basis limited to an as-needed and document *Develop command and control including: structure 1) Ultimate authority 2) Hierarchy of access team response 3) Incident be aware should office *Security of exact number external and nature of links, links, of contact points should drills *Periodic disaster be undertaken of importance *Emphasize to employees security *Hire reputable service with (Beginning providers to and continuing janitorial who have access all persons to the center.) *Seek employee recommendations to minimize staff *Work turnover *Coded entry system should should system entry *Coded reflect hierarchy of access be in should protocol *Software access place to limit system to *External links communication system be minimized, should be should protection firewall utilized where links necessary for all system password *Tiered computer access. of all computer access *Logs be automatically should recorded *See additional computer recommendations, security Table 6 Table 5. Continued. Physical Security MeasuresPhysical Security Measures Logical *Minimum of coded entry of coded entry *Minimum etc.) cards, (swipe system point entry be one main *Should to facility (additional exits by local required as provided fire code, agency needs) *Facility security forces (either or contracted) in-house use and exclusive *Ownership of facility highly desirable of camera monitoring *CCTV access, critical areas inside facility and other detection *Motion desirable devices similar tags identification *Personnel area for *Provide a secure critical computer/communication components room floor control to *Access limited to authorized personnel *Try to maintain low-key - no fencing or presence that attract other measures undue attention *Dedicated communications preferably fiber optic system, be should of all activities *Logs supervisor to provided Potential Threats In order of decreasing threat) ( *Employee mistake/innocent *Employee mistake/innocent oversight employee *Disgruntled hackers *Computer attacks *Terrorists/criminal were not terrorists (While threat a serious considered now, they may be in the future) Issues ATMS Center ATMS Advanced ATMS center facility access
B-25 Measures Administrative Security Administrative (In addition to those cited for cited those to (In addition advanced ATMS center facility access) and control *Command structure is vital *Practice training for major of terms in both incidents, and emergencies public failure of the ATMS center be should equipment, performed regularly *Interagency review/ on of security reevaluation strongly is basis a regular recommended of each the technologies - As agency change, the new with that associated threats be should technology evaluated -Neither management or be should employees allowed to become complacent *When employees are employees *When should security terminated, be modified to reflect changes staffing and media access *News be should extent of access prearranged (In addition to those cited for cited those to (In addition advanced ATMS center facility access) for databases of separate *Use each agency (may be connected on as- individuals by authorized needed basis) firewall of adequate *Provision critical is protection . Table 5. Continued Physical Security MeasuresPhysical Security Measures Logical (In addition to those cited for cited those to (In addition advanced ATMS center facility access) be should access *Physical to areas by operating limited from personnel designated each agency *Given that UPS is most likely be routinely should provided, tested. barriers physical future, **In the to facility’s area, special lead techniques, grounding of and other means walls, a concerted against protecting attack may have to be considered. seriously see information, further -For 23 Reference *Provision for supervisor to to for supervisor *Provision be should system override made emergency test *Routinely available if supply power Potential Threats In order of decreasing threat) ( *Employee mistake/innocent *Employee mistake/innocent oversight employee *Disgruntled hackers *Computer attacks **Terrorists/criminal threat increases (Terrorist operations interagency with not currently but was to be a serious considered they may be in the risk, future) Issues ATMS Center ATMS Advanced ATMS center facility access Continued Interagency operation considerations .
B-26 Computers
Computers have several potential risks associated with them. In order to provide focus to the evaluation of computers, recent statistics regarding the source of computer security problems were used to supplement the information provided by the interviewees.
According to one source, 55% of all computer security losses have been attributed to errors or omissions. An additional 25% of all computer security losses were linked to dishonest and disgruntled employees. Twenty percent of the losses were due to external threats such as disasters, while the remaining 5% was credited to all other cases, including outside hackers (25). The point was thus made that “the two most heavily publicized types of security problems, hackers and viruses, are among the least serious threats to most systems.” The threat from viruses on a percentage basis was also apparently small. As much as 80% of all computer related damage was estimated to be caused internally. Nevertheless, because of the publicity surrounding hackers and viruses, an undue amount of attention is often focused on protecting against external threats (25).
The extent of the risk to computer systems will vary greatly from agency to agency. The determination of how much security is necessary reverts back to the need for risk assessment. When implementing computer security at any level, it is worth noting that the Pentagon’s computers are known among hackers to be “crunchy on the outside, but soft and chewy on the inside” (22). This statement alludes to the need for multiple layers of firewalls and other security measures.
Table 6 provides recommendations that address the basic security measures that should be considered. Several literary resources are available that offer further detailed exploration of computer security measures that can be implemented (23, 25, 26, 29).
B-27 trative Security Measures *A computer security consultant consultant security computer *A evaluate to be retained should and security connections system first exposure highest *Consider security strongest the *Use possible measures be must *Security measures updated to keep pace constantly risks computer changing with employee *An aggressive be program should awareness undertaken be should -employees those use only encouraged to that they applications software are qualified to use of -need for and proper use be emphasized must passwords on be used not should -disks and then home computers work to brought should software of pirated *The use be avoided incident be a dedicated *There must known is that policy reporting employees among all be a dedicated *There must response incident computer team *Aggressive software tiering tiering software *Aggressive be used: should policy level access 1) Basic to individual 2) Access applications: and 3) Additional logins before applications protocol can be affected tiering: with *Commensurate have at should level 1) Base protection virus least have should 2) Mid-level data transfer limited access, of may be limited, records be made should changes have should 3) Upper-level encryption, no-off site read-only data access, format that can be modified only by select employees on both policy a three-strike *Use remote access and in-facility logins logins of all records *Keep Physical Security MeasuresPhysical Security Measures Logical Adminis *Confirmation should always be always should *Confirmation files deleting when required files important of all *Backups and be made routinely should an and at on-site both stored alternate location be run on should *Applications computers personal networked which access critical data off a computer main-frame central should controls *Environmental of protection with be consistent equipment *Keep wiring neatly tucked away around and drinking *Eating be prohibited should equipment components computer *Critical secure, in be located should areas. limited access should checks anti-virus *Routine be performed of anti-virus use *Consider to automatically scan software all E-mail transmissions only into log to users *Allow one computer at a time unless require additional access needs equipment connecting *Cables identified be clearly should Table 6. Recommended Security Measures for Computers. Potential Threats In order of decreasing threat) ( oversight employee *Disgruntled hackers/Viruses *Computer attacks *Terrorists/criminal were not terrorists (While threat a serious considered now, they may be in the future) Issues Computer General mistake/innocent *Employee
B-28 ) Measures Administrative Security Administrative *Computer policy should have a should policy *Computer be care should focus; wide all concentrating avoid to taken other while on one threat efforts the of compromising avenues unguarded. are left system most is that system conscious *Be and repairs during vulnerable (25 upgrades *A computer security consultant consultant security computer *A evaluate to be retained should and security connections system *Security of the Internet be constantly must connections monitored to be paid should *Attention that are happening occurrences Site to other Internet Web providers *If the firewalls detect an intruder, by be notified should person that E-mail that they have been that detected in order to assure legitimate users are not denied access *Evaluate appropriateness of appropriateness *Evaluate to privileges login allowing time-of day and encompass (i.e. persons read-only basis during can only gain access and cannot hours certain change information accessed) combine that passwords *Use and alphanumeric characters require different numbers; level at each access password copying of file extent *Limit *Multi-layered firewalls should should *Multi-layered firewalls be put in place by system the to in” *If “logging should there allowed, is users in system password be a tiered place changes password user *Routine be automatically should required *The latest in anti-virus software be should monitoring incorporated into firewalls ) Table 6. Continued. Physical Security MeasuresPhysical Security Measures Logical *Movement of equipment should should of equipment *Movement be minimized be should maintenance *Routine performed *Use of one-way link from *Use be should Site Web agency’s (i.e read-only considered format) such be established could *Links (i.e. approved users only that have personnel) media news interactive capabilities be maintained should *Backups Site of Web to other agency *Access should Site Web via computers be limited out information putting *Consider to “honey-pot” a controlled in actually many people how see it (23 and steal access Potential Threats In order of decreasing threat) ( *Employee mistake/innocent *Employee mistake/innocent oversight employee *Disgruntled hackers/Viruses *Computer attacks *Terrorists/criminal (While terrorists were not a serious considered threat now, they may be in the future) Issues Computer General Continued Internet Web Site related
B-29 APPLYING SECURITY SYSTEM PRINCIPLES AND RECOMMENDATIONS: A CASE STUDY
The following is a fictitious illustration of the security system development process. It was formulated by the author to demonstrate the use of the procedures and recommendations contained in this paper. (In this scenario, the recommendations contained in Table 5 were used extensively.)
Introduction
The City of Anytown recently constructed a new, state-of-the-art, ATMS center. Anytown, whose population was estimated at 325,000 in the latest census figures, chose to incorporate several agencies into their new ATMS center. The center was originally intended to address the heavy traffic demands placed on Anytown’s roadway network. After an extensive review, the city chose to incorporate police, transit, and emergency management operations into the new facility.
The security of the new center was questioned by several members of the agencies participating in this cooperative venture. In order to satisfy the concerns of all the participating agencies, the facility’s managers requested that a comprehensive security system review be undertaken. Special task forces representing all the participating agencies were formed and a security consultant was retained to assist in the development of security systems for the new center. The purpose of one of the task forces was to evaluate the need for security measures to govern physical access to both the exterior and interior of the facility.
Establishing Goals and Identifying Risks
The task force’s first step in developing a physical access control security system for the new center was to establish the purpose and goals of the security system. This process involved the evaluation of several risks cited by the different member agencies.
Risks involving the internal security systems were first addressed. The police department representatives insisted that access to the facility be strictly controlled. While the need for personnel from the various agencies to access different parts of the facility was agreed upon, it was decided that certain portions of the building should permit limited access. Task force members felt the greatest risks to the facility involved employees of the center inadvertently causing an incident. It was thought that the greatest danger to the system stemmed from employees accessing equipment that they were not qualified to operate. As a result, the control center operations room, the emergency management center, and the rooms housing critical computer and communications equipment were all deemed to require access limitations. While the need to limit access within the building was generally agreed upon, members of the transit office insisted that visitors be allowed to tour their portion of the new facility on a routine basis in order to promote transit ridership. This requirement added another dimension to the security needs of the center.
In addition to internal access control risks, several issues were raised regarding security outside the facility. The new ATMS center was to be located in an economically disadvantaged section of the city as part of a neighborhood revitalization effort. Concerns were raised regarding the physical
B-30 security of employees entering and exiting the facility’s grounds. Additional concerns were voiced about the safety of employees’ vehicles in the parking area. Past incidents in the neighborhood were cited to support the need for external facility security measures. Finally, one of the task force members raised the specter of a terrorist bombing and urged the committee to protect against such actions.
After identifying these potential risks, the task force evaluated the probability and consequences of each of the risks. The internal security issues were deemed to be extremely important in order to insure the protection of information used by the different agencies. It was strongly felt that certain components of the computer and communication equipment justified provision of secured areas. Unauthorized access to these systems was believed to have the potential to severely impact the center’s operations. Given the high visibility associated with the center’s functions, the security of all vital components was deemed essential. In addition to limiting employee access to certain portions of the facility, a need for the capability to host guided tours of the center was agreed upon. The ability to conduct tours within the facility was felt to further justify internal access control measures that prohibited unaccompanied tourists from accessing certain areas of the facility.
The exterior security system also required an extensive risk evaluation process. The possibility of someone gaining unauthorized access to the center was felt to represent both a potential threat to operations and a political nightmare. In addition, the safety of the center’s employees outside of the facility was felt to be of critical importance. The morale of the center’s employees was judged to be a critical component of successful operations. It was therefore deemed imperative that employees were able to operate in the center without fear for the safety of themselves or their property.
As with internal security concerns, the public’s potential perception of the center was also involved in the external security risk evaluation. The center’s management did not want to be viewed as being unable to protect the property and safety of its visitors and employees. Concerns regarding the potential that the center could be held legally responsible for the safety of persons on its grounds, as well as the notion that the police might be seen as unsafe in their own facility, drove the need for external security. In evaluating the extent of the external security measures, the scope of the exterior security system was limited such that it did not address a terrorist bombing. The task force decided that, while such an attack was conceivable, the costs to protect against such an unlikely threat were unjustified.
Having identified several risks associated with access to the new ATMS center, the task force reviewed the potential threats and established three goals for the new center’s security system. The three goals were to limit the extent of unrestricted access within the facility, to provide security for the building’s exterior, and to make the security systems as inconspicuous as possible.
Command Structure
As part of the task force’s evaluation process, a command structure was identified. This command structure was to be reconciled with other aspects of the center’s security when the comprehensive security plan for the facility was finalized. For the purposes of access control, it was decided that a dedicated security office would be established. This office was to staff a full security team to protect the facility. The office was to be headed by a Security Director. The Security Directory was responsible for all security related functions and was subordinate only to the Director
B-31 of the Center. The Security Director was given the task of insuring the security of the center and coordinating all security related incident responses.
The exact nature of the security staff’s command and control functions were to be designated in the comprehensive facility security plan being prepared by a separate committee. As an extension of the security team, each agency participating in the center’s operations was required to designate a contact point for security related issues. Those persons then reported to the Security Director.
In addition to developing a hierarchy among personnel, a tiered security system was agreed upon. This system permitted authorized access of secure areas within the center. The access control system was intended to prevent unauthorized individuals from obtaining access to critical areas within the center while still allowing the center’s employees to enjoy relatively convenient movement. Persons would be required to enter the facility through a security checkpoint in the main lobby. Additional secure areas within each division area (Police, Transit, Traffic, and Emergency Management) were then to be designated by each division and made accessible to select personnel. Access to the ATMS center’s control room floor was to be limited to operators only. Guests of the center were to be guided through selected areas of the facility and were to be provided with a separate viewing area that allowed them to observe the control room floor.
Employee Considerations
While the need for strict access control measures was agreed upon, the task force noted that many employees would have to be given access to the vast majority of the center in order to effectively operate in an interagency environment. At the same time, it was agreed that employees represented the single greatest risk to the center. Their decisions and actions held a central role in the success or failure of the center. The task force thus determined that an extensive tiering system within each division would be required in order to evaluate who was given access to certain areas within the center.
The task force also recognized the need to rely on the integrity of the employees. It was feared that turning the center into the equivalent of Fort Knox would prevent effective implementation of the interagency cooperative concept that the center was intended to advance. The task force thus recommended that the security system be kept as user friendly as possible and that efforts be made to make the system’s components as unobtrusive as possible. Finally, the task force recommended that the center’s management consider security awareness training to insure that employees understood the need for security and exercised security conscious behavior.
Identification of Countermeasures
The task force identified numerous security countermeasures involving facility access. At the forefront of those measures was the use of a security team. In addition, several preventative measures were identified involving physical access. For access considerations within the center, measures identified included lock and key entry systems, card swipe systems, and biometric systems that recognized an individual’s physical features (such as fingerprints). Identification badges were also considered. For the exterior of the center, several additional measures were identified. These included fencing, barbed wire fencing, CCTV camera installations, perimeter alarms, various lighting fixtures,
B-32 audible alarms, and push button incident alarms. Two supplementary vehicle barrier systems were identified for use at the entrance to the facility’s parking area. One of these systems involved an automatic metal gate while the other relied on an underground steel wall that could be raised and lowered using hydraulics.
No logical measures were incorporated directly into the access control portion of this task force’s work other than the statement that the software protocol involved in electronic access systems should reflect the tiered employee privileges at the center. Logical measures were considered extensively in developing a security system for the center’s computers.
Preventative administrative measures that were identified included the need to create an awareness of security issues among employees and the development of a security oriented work ethic. It was noted that support training should be made commensurate with each employee’s access privileges. In addition, all service providers at the center were required to undergo an extensive background check. Tours were to be allowed on a scheduled basis only. Finally, an annual review of access related security measures was considered.
Limiting measures identified by the task force predominately reflected the use of physical countermeasures. The security force itself acted as one limiting measure in that it could respond to incidents with appropriate resources. The need for redundancy in internal access control systems was also cited as a limiting measure. Use of electronically controlled doors was considered at the lobby area, at the computer rooms, at the control room floor, and at the door to the emergency management center. These were felt to be the most critical portions of the center. In addition, a capability to simultaneously “lock down” the center’s access points was considered. CCTV cameras that could be used to observe and document security related incidents were again cited. Additional limiting measures discussed involved administrative actions such as periodic employee reviews. (It was felt that a periodic evaluation of employees involved in sensitive activities might bring potential staffing problems to light.)
Correcting measures involving facility access primarily consisted of administrative measures. It was felt that, in the event of a security breach, correcting measures would mainly revolve around an evaluation of the breach and how the security system had failed. Other administrative measures identified included a mandatory review of all access privileges granted and frequent updating of the rules and regulations that governed them. The security force was again cited as a resource to facilitate these reviews.
Selection of Countermeasures
After identifying and compiling a list of potential countermeasures, the task force chose those security measures that it would recommend. The primary recommendation of the task force was that a security team be utilized to provide security to the center. In order to supplement the security team, the task force recommended the use of several internal security measures. Internal access was to be controlled through a combination of both lock and key and swipe card systems. All office doors were to have a door lock and key. In addition, four critical areas would be protected by swipe card technology.
B-33 The swipe cards were chosen for their proven performance record and would require each individual to carry a swipe card for access purposes. Swipe card readers were to be located at the facility entrance immediately inside the main lobby area, at the entrance(s) to the computer and communications room, at the entrance(s) to the control room floor, and at the emergency management center entrance. Each of these readers would be programmed to allow only certain employees into the respective area that they controlled. (The center’s management was to determine the employee tiering system to be used.) Personnel identification tags incorporating swipe card technology were to be used to provide tiered access to these areas as well as to provide a means of identification. CCTV cameras were to be located to permit constant monitoring of each of these entrance points and a capability for the security office to remotely lock these doors was provided.
Several external security measures were also adopted. These included the use of a small, architecturally designed masonry wall that would delineate the perimeter of the facility without attracting undo attention. Both the barbed wire fencing and vehicle barrier systems were eliminated from consideration in order to limit the amount of attention the center drew. CCTV cameras were to be located at inconspicuous points around the ATMS center and its parking facilities in order to permit constant monitoring of the facilities’ exterior. Infrared-based perimeter alarms were to be installed immediately inside of the masonry walls to detect intruders. The CCTV camera images and the perimeter alarms were then to be directly relayed into the security office. In addition to these measures, a generous exterior lighting system was to be provided in the parking area. The concept of push button incident alarms was abandoned in favor of reliance on the security team monitoring the other external security equipment.
A decision on the logical security needs involving the swipe card technology was deferred to the comprehensive facility security committee considering employee privileges. Several administrative recommendations were offered by the task force. These included a command structure for the security team, mandatory security background checks of all service providers, routine employee performance evaluations, a need for employee security awareness training, tour scheduling requirements, and an annual security review process.
Implementation
Having identified the physical, logical, and administrative security measures that should be used, the task force sent its recommendations to the committee developing the comprehensive security system for the center. The recommendations were supported with thorough documentation of the goals and methodology the task force considered in reaching their final decision. The access control task force’s recommendations were then reviewed by the committee and reconciled with other task forces’ findings in developing a comprehensive security system for Anytown’s ATMS center.
B-34 CONCLUSIONS
This paper has attempted to create a heightened awareness of the security issues surrounding ITS and ATMS technology applications by highlighting some of the key concepts discussed in telephone interviews with transportation and technology experts. In addition to identifying past transportation related security breaches, a brief review of some of the threats that have been encountered by other technology-based industries was offered. Recommendations developed by the author regarding basic security policy and implementation were then presented for consideration by the reader. Finally, a fictitious case study that illustrated the process of developing a security system for an advanced ATMS center was discussed. The case study incorporated both the methodology and recommendations for developing a security system presented in this paper.
As one reflects on this paper and considers the relevance of the information presented to their own security experiences, it is important to recognize that a lack of security breaches does not necessarily indicate that security issues have been adequately addressed. As the world and the technology that drives it continues to evolve, we, as providers of the nation’s transportation system, must evolve our thinking to reflect this ever changing environment.
The need for security in ITS and ATMS technologies and their role in the transportation industry has not gone unnoted by the industry’s experts. The International Standards Organization (ISO) Technology Committee 204 recently began work regarding security issues (30).
While ISO Committee 204's final report and recommendations may not be available for some time, there are several interim considerations. The people who operate ITS and ATMS technologies must be properly trained and hold an astute awareness of the ramifications of their actions. All employees should be involved in actively supporting a given system’s security. That security must be structured such that it recognizes that those technologies that keep out intruders also make life difficult for the intended users. No system’s security can be guaranteed and, with the spectrum of potential threats ranging from employee mistakes to bombing, it may be valuable to consider that anyone could physically destroy equipment but it requires knowledge to interfere with it.
This report has by no means addressed all of the issues that must be considered in confronting security issues, rather it is an attempt to offer information that is felt to be commonly overlooked in the day to day work of transportation professionals. It is the hope of this author that the content of this paper will open new avenues of thought and discussion for transportation engineers, system managers, and system operators by sharing the experiences and knowledge of others.
B-35 ACKNOWLEDGMENTS
This paper was prepared for Advanced Surface Transportation Systems, a graduate course in Transportation Engineering at Texas A&M University. The instructor for this course was Dr. Conrad L. Dudek. Professional mentors were Walter Dunn, Ginger Gherardi, Leslie Jacobson, Jack Kay, Colin Rayman, and Thomas Werner. The author gratefully acknowledges these professionals for their time and effort in supporting this course. The author would like to extend special appreciation to Jack Kay, Colin Rayman, Kevin Balke, and Dr. Dudek for their support and insights in preparing this paper. Finally, special thanks are offered to the many people listed below and referenced throughout the paper for taking the time to share their experiences, thoughts, and opinions with the author.
C Mr. Ron Dahl, Minnesota Department of Transportation, Metro Division Traffic Management Center C Mr. Bill Dawson, BDM International, Inc. C Mr. Tip Franklin, TRW, Inc. C Ms. Ginger Gherardi, Ventura County Transportation Commission C Mr. Daniel Grate, Jr., State Highway Administration, Maryland Department of Transportation C Mr. Dan Hickman, Texas Transportation Institute, Houston Office C Mr. Pat Irwin, San Antonio TransGuide C Mr. Glenn Jonas, Arizona Department of Transportation Traffic Operations Center C Mr. Leslie Kelman, The Municipality of Metropolitan Toronto, Transportation Department C Mr. Joe McDermott, Illinois Department of Transportation, District One C Mr. Jan Meilhede, New York State Department of Transportation, Traffic & Safety Region One C Mr. Emmanuel Morala, Ministry of Transportation of Ontario, Traffic Management Central Region Operation, Computer Control Systems Section C Mr. Mark Morse, Washington State Department of Transportation C Mr. Vince Pearce, AlliedSignal Inc., Transportation Systems & Services C Mr. Robert Rausch, JHK & Associates C Mr. David Roper, Roper and Associates, Inc. C Mr. William W. Stoeckert, Connecticut Department of Transportation C Ms. Amity Trowbridge, Washington State Department of Transportation C Mr. Doug Wiersig, Houston TranStar
B-36 REFERENCES
1. Johnson, C. Accelerating ITS Deployment: A Report from the U.S. DOT. ITE Journal, Vol. 65, No.12, December 1995, pp. 64-67.
2. Roberts, S.V., T. Gest, K.T. Walsh, and J. Popkin. Terror in The Heartland. U.S. News & World Report, Vol. 118, No. 18, May 1995, pp. 26-29.
3. Mr. Robert Rausch. JHK & Associates-Atlanta, Georgia. Telephone interview conducted June 16, 1996.
4. Mr. William Stoeckert. Connecticut Department of Transportation. Telephone interview conducted June 21, 1996.
5. Mr. Jan Meilhede. New York State Department of Transportation. Telephone interview conducted June 11, 1996.
6. Mr. Vince Pearce. AlliedSignal Inc. Telephone interview conducted June 18, 1996.
7. Mr. David Roper. Roper and Associates, Inc. Telephone interview conducted June 24, 1996.
8. Mr. Pat Irwin. San Antonio TransGuide. Telephone interview conducted June 12, 1996.
9. Collinson, H. Abstracts of Recent Articles and Literature. Computers and Security, Vol. 13, No. 8, 1994, pp. 651.
10. Mr. Daniel Grate, Jr. State Highway Administration, Maryland Department of Transportation. Telephone interview conducted June 20, 1996.
11. Ms. Amity Trowbridge. Washington State Department of Transportation. Telephone interview conducted June 18, 1996.
12. Mr. Ron Dahl. Minnesota Department of Transportation. Telephone interview conducted June 18, 1996.
13. Mr. Emmanuel Morala. Ministry of Transportation of Ontario. Telephone interview conducted June 20, 1996.
14. Mr. Glenn Jonas. Arizona Department of Transportation. Telephone interview conducted June 18, 1996.
15. Correspondence from Mr. Mark Conrad to Mr. Leslie Kelman. Transportation Department, The Municipality of Metropolitan Toronto. Dated July 18, 1996.
16. Mr. Doug Wiersig. Houston TranStar. Telephone interview conducted on June 16, 1996.
B-37 17. Mr. Joe McDermott. Illinois Department of Transportation. Telephone interview conducted June 21, 1996.
18. Mr. Leslie W. Kelman. Transportation Department, The Municipality of Metropolitan Toronto. Telephone interview conducted on June 19, 1996.
19. Mr. Tip Franklin. TRW, Inc. Telephone interview conducted June 13, 1996.
20. Mr. Dan Hickman. Texas Transportation Institute. Telephone interview conducted July 2, 1996.
21. Ms. Ginger Gherardi. Ventura County Transportation Commission. Personal conversation conducted June 1, 1996.
22. Waller, D. Onward Cyber Soldiers. TIME Magazine. Vol. 146, No. 8, August 21, 1995, pp. 38-44.
23. Cohen, F.B. Protection and Security on The Information Superhighway. John Wiley and Sons, Inc., New York, 1995.
24. Sandberg, J. GE Says Computers Linked to Internet Were Infiltrated. Wall Street Journal, Vo.l 13, No. 224, Nov. 28, 1994, pp. B5.
25. Securing Client/Server Computer Networks. McGraw-Hill Series on Computer Communications. McGraw-Hill, New York, 1996.
26. Olnes, J. Development of Security Policies. Computers & Security, Vol. 8, No. 8, 1994, pp. 628-636.
27. Cooper, W., and R. DeGrazio. Building Security: An Architect’s Guide. Progressive Architecture, Vol. 76, No. 3, March 1995, pp. 78-81.
28. Aarons, S. Access Control Systems. The Architect’s Journal. Vol. 201, No. 15, April 13, 1995, pp. 35-36.
29. Sydmonds, I. Security in Distributed and Client/Server Systems-A Management View. Computers & Security, Vol. 13, No. 6, 1994, pp. 473-480.
30. Mr. Bill Dawson. BDM International, Inc. Telephone interview conducted June 21, 1996.
B-38 APPENDIX TELEPHONE INTERVIEW QUESTIONS
It was anticipated that each telephone interview would be unique in the topics covered depending on the knowledge of the interviewee. Based on the responses and knowledge of the interviewee, the conversation was permitted to move towards their area of specialization. In order to direct the initial phases of the phone call and to focus the contents of the response, the following questions were pursued first:
1) Are you aware of breaches of your system’s security or of instances in which it was tampered with? -If yes, whom was the perpetrator and what was the impact? (Specific identity is not necessary, the intent of this question is to determine what background the perpetrator represented, i.e. computer hacker, employee, contractor crews, employee of different agency, etc.) -Did any of the security problems involve the following items: < Changeable Message Signs (CMSs), unauthorized message displays, etc. < Cellular phone dependent technologies (i.e. CMS or other remote unit communications) < Interagency computer connections < Computer viruses < Computer hackers < Internet connections/backdoor hacking < Computerized traffic signal control systems < Ramp metering controls < Tampering with/sabotage of CCTV installations < Toll collection/accounting systems < “Smart Card” or similar electronic fare technologies -Follow up with probing questions such as: After asking about CMSs, Do you rely on cellular phone technologies to communicate with field equipment such as changeable message signs and, if so, are you aware of problems with stolen numbers/unauthorized communications?
2) Who do you consider to represent the greatest security risk to your system both in likelihood of a problem and the extent of damage inflicted: computer hackers, a disgruntled employee, interagency activities, innocent tampering, theft of information by outside influences, or terrorist threats?
3) Based on response to Questions 1 & 2, what security measures are in place within facility/computer systems? -Are there “firewalls” between hierarchial levels of system/interagency connections? -Are there backdoors into computer system?/What danger do they pose? -Are new actions to insure security being taken/explored? -Is physical access to your facility protected/monitored? *Interviewer mentions EMP bomb if appropriate - pursue discussion there.
4) What do you perceive as security risks/potential threats to your system? -Does your ATMS system incorporate police/fire/transit operations?
B-39 Chris Brehmer received an Associate of Science in Engineering Science from Fulton-Montgomery Community College in 1993 and a Bachelor of Science in Civil and Environmental Engineering from Clarkson University in 1995. Currently, Chris is pursuing a Master of Science degree in Civil Engineering while working for the Texas Transportation Institute as a Graduate Research Assistant. Past and present university activities include: Tau Beta Pi, Chi Epsilon, ASCE, ITS America, and the Institute of Transportation Engineers (where he will be assuming the position of Corresponding Secretary on June 1). His areas of interest include: traffic engineering and operations.
B-40 IMPEDIMENTS TO THE EFFECTIVE USE OF PORTABLE VARIABLE MESSAGE SIGNS AT FREEWAY WORK ZONES
by
David M. Halloin
Professional Mentors Thomas C. Werner, P.E. New York State Department of Transportation
and
Walter M. Dunn, Jr., P.E. Dunn Engineering Associates
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, TX
August 1996 SUMMARY
Portable variable message signs have the ability to provide motorists with real-time information regarding changes in roadway traffic conditions and construction activities as well as providing motorists with information about the actions that should be taken due to these conditions. Because they can relay numerous messages about current freeway construction and maintenance work zone conditions, and because they have the ability to command attention, they are very effective when used properly. However, when they are not used properly these signs begin to lose their ability to command attention and are ignored by motorists. In order for the signs to be effective, everything possible must be done to assure that messages displayed on these devices are accurate and current at all times.
To improve the operations of these devices, one must determine where the need for improvement is most prevalent. This study used a survey to examine the practices of numerous entities across the United States and Canada in an attempt to identify impediments to the effective and efficient use of these portable variable message signs used in freeway construction and maintenance work zones.
Once information about operating practices were gathered from the participating entities, the various operating procedures used were compared to procedures recommended by researchers who determined the most beneficial methods of operating these devices. Discrepancies between operating procedures and recommended procedures were noted, along with comments by the entities as to the effectiveness with which the signs performed specific duties. Through this process impediments were associated with certain practices.
Recommendations for improving PVMS operations through dealing with impediments were made in many different levels of sign operation. Recommendations in this report deal with personnel issues as well as equipment and technologies used. Certain guidelines and standards are suggested as reference materials to be used in signing operations and in personnel training. Specific guidelines are recommended regarding message length and other message display issues. Techniques for signing and personnel procedures are also addressed.
C-ii TABLE OF CONTENTS
INTRODUCTION ...... C-1
BACKGROUND ...... C-2 Problem Statement ...... C-2 Research Objectives ...... C-2 Scope of Research ...... C-2
PORTABLE VARIABLE MESSAGE SIGNS ...... C-3 Introduction ...... C-3 Existing MUTCD Standards ...... C-3 Physical Guidelines ...... C-3 Positioning Guidelines ...... C-4 Message Guidelines ...... C-4 PVMS Operations ...... C-4 Uses ...... C-4 Hardware ...... C-5 Displays ...... C-5 Personnel ...... C-5 Messages ...... C-6
STUDY DESIGN ...... C-7
SURVEY RESULTS ...... C-8
IMPEDIMENTS TO THE EFFECTIVE USE OF PVMSs ...... C-11 Message Length ...... C-11 Lack of Signing Guidelines, References, and Operator Training ...... C-13 Methods of Monitoring Site Conditions and Messages ...... C-13 Sunglasses Filtering LED Emissions ...... C-14 Lack of Authority for Speed Control ...... C-15 Overuse of PVMSs for Lane Changes ...... C-15 Prolonged Use of a Message to Alert Motorists to Future Changes in Conditions ...... C-16 Displaying Default Messages ...... C-16 Operator Boredom ...... C-16 Outdated or High Maintenance Equipment ...... C-17 Cost and Manpower Necessary to Operate System ...... C-17 Motorist Recognition of Abbreviations and Symbols...... C-17
C-iii RECOMMENDATIONS ...... C-18 Commitment to System ...... C-18 Manpower ...... C-18 Equipment ...... C-18 Guidelines and Standards ...... C-19 Operator’s Manual ...... C-19 Training ...... C-19 Message Guidelines ...... C-20 Shortening Messages ...... C-20 Other Guidelines ...... C-21 Signing Techniques ...... C-21 Procedures for Personnel ...... C-22 Amend Policy or Legislation ...... C-22 System Evaluation ...... C-23 Ideas for Future Research ...... C-23
EVALUATION OF THE VIRGINIA MANUAL (4) ...... C-24 Strengths ...... C-24 Areas for Improvement ...... C-25
ACKNOWLEDGMENTS ...... C-26
REFERENCES ...... C-27
APPENDIX ...... C-30
C-iv INTRODUCTION
Portable variable message signs (PVMSs) are used in numerous situations to provide many types of information to motorists. The use of PVMSs for construction and maintenance work zone projects is one of their most important applications. This is due to their high visibility and ability to relay a variety of real-time information based on the current conditions within the work zone. Each year, Maintenance and construction work is increasing on freeways in the United States. This work has negative repercussions on traffic flow and safety if correct measures are not taken to manage and sign the work zone. Management and signing for these conditions often is best performed through the use of innovative traffic control devices such as PVMSs. These devices typically are used to make drivers aware that construction is occurring, reduce speeds, notify motorists of changing traffic patterns, and to alert motorists of delays.
In using PVMSs as traffic control devices, it is important that they be developed and operated as efficiently and uniformly as possible. These signs should be positioned at locations where the message being displayed has the most desirable effect. PVMSs are operated by a variety of individuals, including department of transportation workers in the areas of traffic management, construction, and maintenance, contractors working at the construction site, and in some cases by police officers. It is important that they be operated properly, providing real-time information, and that they not be used merely as static signs.
C-1 BACKGROUND
Problem Statement
PVMSs often are used for safety and information signing at construction and maintenance work zones. These signs have an advantage over static work zone signing, since they are able to relay a variety of messages relevant to the current conditions within the work zone, in addition to being highly visible, their presence alone alerts motorists that there is an important message to be conveyed. However these signs lose the ability to command attention when they are not used properly. PVMSs provide motorists with real-time information regarding changes in roadway conditions and construction activities and can relay messages on what actions need to be taken by motorists due to these conditions. When inaccurate messages are frequently displayed, or when messages are not changed regularly, the credibility of the PVMS displays is lost and motorists begin to ignore these signs.
It is generally felt, among members of the transportation community, that use of these signs is not optimum. To be used effectively they must relay a needed, accurate, and timely message to motorists. There are impediments to the effective and efficient use and operation of PVMSs for work zones. In order to correct this problem, these impediments need to first be identified. Once impediments are identified they can be dealt with on an individual level and suggestions can be made on how to overcome them.
Research Objectives
The objectives of this study were to 1) first determine through literature review and interviews what impediments exist to the effective and efficient use and operation of portable variable message signs in work zones and 2) develop recommendations on how these impediments can be overcome. These impediments may be different for different sign applications. Impediments may also differ for different types of maintenance work zones and construction zones on freeways.
Scope of Research
After investigating the practices and experiences of various state departments of transportation and identifying some of these impediments, the author recommended means of overcoming these problems and improving the effectiveness of PVMS signing. Since this paper focuses exclusively on the use of PVMSs in freeway work zones, the agencies whose practices were investigated were limited to state agencies who dealt with freeway operations.
C-2 PORTABLE VARIABLE MESSAGE SIGNS
Introduction
Variable message signs can be either permanently installed or made transportable in order to best meet the specific needs of the highway agency operating them. There are three different portable variable message sign designs that differ in mode of transportability (1,2). The most commonly used type of PVMS is that mounted on either a truck or trailer, which is driven or towed to a specific location and parked (1). The two other types of signs are pickup signs which sit on legs and are hauled to the desired locations by trucks, and ground mounted signs for which legs are permanently mounted at certain locations and only the display boards are transported (2).
The Manual on Uniform Traffic Control Devices (3), or MUTCD, describes PVMSs as traffic control devices with the flexibility to display a variety of messages to fit the needs of road and street authorities. These devices are unique in that they have the ability, when used properly, to provide motorists with accurate, reliable, up-to-date information on traffic and roadway conditions. The messages presented to motorists through this media are, in most cases, only limited by the number of characters which can be displayed on the sign, and by the amount of time freeway motorists are within the legibility area of the sign.
Existing MUTCD Standards
The primary purpose of PVMSs as stated by part VI of the MUTCD (3), should be to advise motorists of unexpected traffic and routing situations in temporary traffic control zones. The manual recognizes that these signs cannot always conform to the exact sign shape, color, and dimensions specified as standards. It gives some physical, positioning, and message guidelines, but it does not do a thorough job of setting standards.
Physical Guidelines
The PVMS units should be visible to motorists at a distance of ½ mile under ideal daytime and nighttime conditions when placed near the roadway for operation. When displaying a message, the bottom of the PVMS message panels shall be a minimum of seven feet above the roadway surface and the message being displayed should be legible from all lanes of traffic at a minimum distance of 650 feet from the sign (3).
The control system for PVMSs shall include the following features: a display frame upon which messages can be reviewed before display on the sign face, the capability to provide an automatic programmed default message if power failure occurs, and a backup battery to maintain memory and so that power can be provided to continue operation of the sign when failure of the primary power source occurs (3).
C-3 Positioning Guidelines
Part VI of the MUTCD (3) specifies that a spacing of at least 800 feet should be provided between guide signs. Typically PVMSs should be positioned in advance of any other temporary traffic control zone signing, and should not replace any required signing. When two signs are necessary to communicate multiple frame messages, they should be placed on the same side of the roadway, and these signs should be separated by a minimum distance of 1,000 feet. Note that this separation distance of 1,000 feet is specified for freeway speeds of 55 mph (1). More spacing should be provided in areas where the 85th percentile speeds are in excess of 55 mph.
Message Guidelines
The MUTCD (3), part VI, also states that messages designed to be displayed on PVMSs should consider the following factors:
C No more than two frames should be used within any message cycle; C Messages should be made as brief as possible; C When using abbreviations, they should be easily understood; C The entire message cycle should be readable at least twice at the posted speed, the off-peak 85th percentile speed prior to work starting, or the anticipated operating speed; and C Messages shall not scroll horizontally or vertically across the face of the sign.
Due to the limited legibility time available to motorists traveling at freeway speeds, it may not be feasible for multiple frame messages to be read twice. Standards state that a maximum of two frames should be used to relay a message (2) but suggest that even two frames may be too many for motorists to process in the legibility time available. Thus, additional message frames should be used very judiciously(4).
PVMS Operations
Uses
The main purpose for using PVMSs is to advise motorists of unexpected traffic and routing situations. There are numerous applications for which PVMSs can be used at freeway construction and maintenance work zones, due to their ability to perform many duties and to attract attention(1). They can provide motorists with real-time warnings of conditions that exist within the work zone, as well as advising motorists of the best course of action(5). Some uses for which these signs are typically used in work zones are listed here (1,3,5,6,7):
C New detours; C Change in detours; C Introduction of a lane drop where a continuous lane once existed; C Special speed control measures; C Periodic use of flaggers; C Location where sight distance is restricted and congestion occurs due to a lane closure;
C-4 C Referencing Highway Advisory Radio (HAR); and C Alert motorists of future changes which will be made to current traffic conditions (i.e. Construction to begin at a future date).
Hardware
The hardware provided for use with variable message signs continues to change as new technologies are developed and tested. Over the past several years advances in telecommunications technology have made it possible for trailer-mounted PVMSs to be operated remotely using computer based station operation, voice synthesizer operation, telephone land line operation, or cellular telephone operation. In order to power these signs, there is another relatively new technology which is being used on PVMSs , solar power. PVMSs are primarily powered by batteries fueled through solar panels or by diesel engines. Backup batteries are typically also a part of the sign unit.
Displays
PVMSs used for marking high-density urban freeways usually have three lines of eight characters each, with character heights of 18 inches (1). These signs use a variety of technologies for displaying messages, such as bulb matrices, rotating drums, flip disks, light emitting diodes (LED), and fiber optics, and vary in their display capabilities (1). Some of these devices display a small number of limited word messages from a preset library, some use combinations of characters of a specific size, and others have the ability to display symbols that occupy the entire frame (6). PVMSs, when used properly, have an advantage over static signs in their ability to attract motorist attention. This effect can be magnified by making a message flash on and off, especially if it is a single frame message.
As of 1986, bulb matrix signs were the most commonly used form of PVMS used at freeway work zones (5). Most of the signs operating in the United States today use incandescent bulbs, fiber optics, or a hybrid combination of one of these technologies with reflective disks, to increase nighttime visibility. The new trend in signing is being led by newer LED technology because they use less energy and therefore are cheaper to operate and work better on solar powered devices(8). LEDs are solid state devices that glow when voltage is applied to them. The writing speed of these devices is much faster than that of the devices using electro-mechanical technology, such as flip disk or rotating drum (1), allowing messages to be changed almost instantaneously. These signs have high reliability and can endure approximately 12 years of continuous operation, while consuming a relatively low amount of power (1).
Personnel
Messages must be kept accurate, up-to-date, and reliable in order to maintain credibility. To achieve this, it is important that information be readily available about traffic conditions, as knowledge of these conditions determines the message to be relayed to motorists. It is also very important to assure that the correct message is displayed, as credibility may be lost if motorists respond to real-time information and believe that the response has worsened their situation. The task of ensuring sign credibility may call for extra time and personnel to be made available for operating
C-5 these signs (1). Acceptable methods of determining message accuracy include credible commercial traffic reporters, police (state, county, or local) and visual inspection of the scene by agency personnel (6). The signs are actually operated by a variety of individuals from traffic, construction, maintenance, and traffic operation center branches of the departments of transportation, as well as by contractors, and in some cases by police.
Messages
Messages displayed on PVMSs should be carefully thought out, to keep the message as short as possible, while still conveying the desired message. This brevity of messages is very important because the time a freeway motorist has to read a message presented to him is only a few seconds. These messages should be composed of the following elements: (1)
C A problem statement (maintenance, construction, etc.); C An effect statement (delay, congestion, etc.); C An attention statement (who information is directed towards); and C An action statement (what to do)
Unnecessary information should be avoided, along with implied information Therefore, at times only the problem and action statements need to be provided, as some statements can be assumed(1).
Message familiarity is a very important factor influencing the reading time of messages, as well as the ability of motorists to correctly understand the message (1). Therefore it is important that some standards be used in preparing messages. Some agencies choose their messages from a pre- approved list of messages, while other agencies develop messages to fit with certain circumstances as they are needed. Familiarity is particularly important when using abbreviations and symbols on the signs. However, the use of symbols is limited, mostly because few older model PVMSs have the capabilities to use them.
Message format is the order in which words are displayed in a message. Static format is display of an entire message on a single frame. This type of message most easily conforms to standards, but can only provide a very limited amount of information. Sequential format involves divideding the message into two or more parts, each displayed for a set period of time. An alternative to sequencing a message on a single sign is to “chunk” the message; divide it into two compatible units of information, and display it on two separate signs (2). This technique is best used when displaying messages that exceed the maximum of two frames.
C-6 STUDY DESIGN
To determine what impediments exist to the effective use of PVMSs in freeway construction and maintenance work zones, a study was done to determine the most beneficial methods for operating these signs, as well as to determine the methods being practiced by different state departments of transportation and governmental agencies. Information from the literature review was used to develop a written survey, and later as a set of guidelines to compare with survey findings. Phone contact was made with representatives of 12 State Departments of Transportation and related State agencies, located in 8 U.S. states and in Canada.(At the time this report was prepared 10 of these contacts had responded) The respondants are listed in Table 1.
Table 1. Respondants to PVMS Survey.
State/Agency Entity Virginia (9) Department of Transportation Washington (10) Department of Transportation (NW Region) New York (8) Department of Transportation TRANSCOM (11) Government Agency (New Jersey/New York Area) Texas (12) Department of Transportation (Houston) TRANSGUIDE (13) TxDOT (San Antonio) Ontario (14) Ministry of Transportation California (15) Department of Transportation Wisconsin (16) Department of Transportation INFORM (17) NYSDOT (Long Island) (#) Reference
The survey is presented in the Appendix and the feedback from the survey was used to determine impediments to the effective use of PVMSs and in suggesting improvements. A summation of survey results is presented in the following section of this report.
C-7 SURVEY RESULTS
Each of the ten agencies responding to the survey currently uses PVMSs for multiple applications at freeway work zones. All reporting agencies use these devices to alert drivers of closed lanes, and for diverting drivers to different routes. Table 2 shows the breakdown of applications for which PVMSs are used.
Table 2. Use of PVMSs in Freeway Work Zones.
Use Percentage of Agencies Close lanes 100 Divert traffic to a different route 100 Alert motorists of future change to 80 current conditions Shift lanes 60 Change travel speed 50 Reference HAR 30
This survey found that 90 percent of these agencies still operate PVMSs from controls located on the signs, either through operators located at the work zone or through mobile units. Some newer signs are operated from a variety of locations, often from a traffic management center (TMC), using cellular call-in technology. Sixty percent of these agencies have the capability of operating at least a portion of their signs using this method. TRANSCOM only operates their signs within range of their video surveillance system and operates them exclusively through cellular communications.
The PVMSs are operated by a variety of individuals from traffic, construction, maintenance, and traffic operation center (TOC) branches of the departments of transportation, as well as by contractors, and in some cases by police. Table 3 is a breakdown of personnel operating signs for those agencies surveyed. When personnel other than those from the TOC are operating the signs, the messages displayed are often first authorized by the TOC.
C-8 Table 3. Agency Use of Various Personnel to Operate PVMSs.
Agency Personnel Percentage of Agencies Maintenance 70 Department of Traffic 60 Transportation Traffic operations center 50 Construction (EIC) 40 Contractor 80 Other Police 10
All of the reporting agencies use PVMS displays with three lines, capable of displaying eight characters per line, set up to display 18 inch tall characters. They all use signs with three panels but 20 percent also still operate some, older, single panel signs that can only provide very limited information, even more limited than the three panel signs. Uppercase lettering is currently used exclusively, by these agencies. Each agency also stated that they primarily use multiple frame messages, with half of them using up to three frames to convey a single message. When displaying these multiple frame messages the time allowed per frame varied from 1 to 3 seconds. When the message being displayed is too long to be properly displayed in the available motorist exposure time, instead of shortening the message presented, some agencies simply shorten the time each frame is displayed.
All agencies claimed to use abbreviations in their messages, but it was noted that they were typically used as a last resort. Abbreviations are used to display words of more than eight characters or to shorten messages to fit onto one or two frames, when additional frames would otherwise be required. Only 20 percent of the agencies currently use symbols for displaying messages, but this will likely increase as it is a relatively new idea and can only be performed with newer model PVMSs having symbol capabilities.
Sixty percent of the agencies selected at least a portion of the messages displayed on their signs from a pre-approved listing of messages.
Forty percent reported using preset default messages on their signs. Some of the messages, listed in the survey, allow the PVMS to display useful information even in the default mode. Default messages listed included notification of future changes in traffic and roadway conditions for connecting routes and generalized work zone messages (i.e. PROCEED WITH CAUTION and ROAD WORK AHEAD). One agency listed a default message as “PLEASE DRIVE SAFELY,” though this message shows that the sign is functioning, one must be careful that motorists do not see this message or any other default message for too long a period of time. A motorist may begin to ignore the signs and may not notice when they are changed to display important information, if they have become accustomed to seeing the same default message repeatedly.
C-9 When PVMSs are used to alert motorists of future changes to current traffic and roadway conditions, messages tend to be lengthy and fill two frames. This should not be a problem because the information is not vital and will typically be viewed on multiple occasions by drivers before the event takes place. The signs are placed prior to the time when road work is planned to begin so drivers can change their travel patterns, thus lessening impacts when road work is begun. Routing information is sometimes even provided in these advanced messages.
The use of PVMSs to change motorist speeds at and around work zones is reported, by half of the agencies participating in the survey, to be effective. The New Jersey Department of Transportation does not use PVMSs to manage travel speeds at freeway work zones because these signs are not regulatory signs, and cannot be enforced as such. Most agencies using the signs for speed management reported using multiple frame messages (e.g. SPEED ZONE AHEAD / SPEED LIMIT 50 MPH), when a single frame message like one used in Texas (REDUCE SPEED 50 MPH) presents practically the same message while avoiding potential problems associated with displaying multiple frame messages.
C-10 IMPEDIMENTS TO THE EFFECTIVE USE OF PVMSs
Message Length
Messages being displayed often are too long to be displayed within a motorist’s exposure time. This is probably the largest impediment to the effectiveness of PVMSs, because if a message is too long to be read and understood by most motorists, its utility is greatly diminished.
All entities responding to the survey stated that they primarily use multiple frame messages, half of them using messages as long as three frames. When displaying these messages the time allowed per frame varies among agencies, between 1 and 3 seconds. The messages being used are generally too long due to the limited time that a motorist is within the legibility range of a PVMS. To compensate for this lack of motorist exposure time, one agency responding to the survey is displaying some messages for less than two seconds per frame.
Research demonstrates that a minimum exposure time of one second per short word or two seconds per unit of information should be used when presenting messages to unfamiliar motorists (18). As all words or abbreviations displayed on PVMSs are short (no more than eight characters) one second per word, or two seconds per frame, displaying less than three words can be used as a guideline. Thus, there is only time to relay a very limited amount of information to motorists, especially with the establishment of higher freeway speeds.
Exposure time plots ( Figures 1, 2, and 3), show the limited time that is available for presenting messages to motorists traveling at different speeds. These plots were developed for this study, using a table of unreadable distances (1) and a standard assumed legibility distance for PVMSs of 650 feet (2), along with a series of calculations (4) that would normally be followed by operators. Note that for a typical freeway with two lanes in one direction, a speed of 65 mph, and a PVMS posted 15 feet from the pavement, a motorist will only be exposed to a message for approximately 4 ½ seconds. This is barely enough time to display a two frame message once, and definitely not enough time to display it twice as the MUTCD specifies.
C-11 Figure 1. Motorist Exposure Time for PVMS at Various Speeds (2 Lanes of Traffic).
9.0
8.0
35 7.0 40 6.0 45
5.0 50 55 60 4.0 65 70 3.0 Exposure Time (seconds) 2.0
1.0
0.0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Dista nce from close side of P V M S to e dge of roa d (ft.)
Figure 2. Motorist Exposure Time for PVMS at Various Speeds (3 Lanes of Traffic).
C-12 8.0
7.0
6.0 35
40 5.0 45 50 4.0 55 60 65 3.0 70
Exposure Time (seconds) 2.0
1.0
0.0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Distance from close side of PVM S to edge of road (ft.)
Figure 3. Motorist Exposure Time for PVMS at Various Speeds (4 Lanes of Traffic).
Signing Guidelines, References, and Operator Training
PVMSs are operated by personnel from numerous backgrounds, performing many tasks in addition to sign operation. Survey responses indicate that agencies have insufficient personnel with proper training in the area of operation of PVMs. Operators have difficulty designing brief messages that relay all necessary information. Only 60 percent of the reporting agencies surveyed select messages displayed on their PVMSs from a pre-approved listing of messages. Insufficient standards in the area of PVMS operation make it difficult to find documentation on operating the signs unless the agencies have developed or adopted an official policy and references to be used in this process.
Methods of Monitoring Site Conditions and Messages
In order to operate PVMSs and to post accurate, reliable, and up-to-date messages from a location other than the sign itself, it is important that the appropriate information be provided to the operating staff (19). Accurate information needs to be provided about roadway conditions and activities taking place in the construction and maintenance work zones, as well as the accuracy of the message being displayed. Acceptable methods of determining this information include credible traffic reporters, police, as well as means of visual inspection of the scene by agency personnel. Phone calls from motorists on the freeway can provide operators with an idea that a problem may exist, but can provide misleading or inaccurate information (6).
C-13 Currently drive-by checking is a method used by 90 percent of those agencies responding to the survey. These agencies see this as a problem due to the high cost associated with the number of personnel required to operate a large system. Other methods of monitoring signs have other problems. Video monitoring of the sites and displays would be an ideal solution, but is expensive, limiting its use for temporary locations like those typically signed with PVMSs. Cellular monitoring of the displays involves problems with people cloning the outgoing signal from the signs, obtaining the signal and using this to make unauthorized calls. Cellular sign monitoring also fails to aid in monitoring site condition, thus continuing the need for drive-by surveillance.
Sunglasses Filtering LED Emissions
The Federal Highway Administration (FHWA) is doing research on filtering of LED emissions by sunglasses, based on reports from motorists stating that sunglasses are blocking out the messages on light emitting diode PVMSs (20). They found that there is a severe attenuation of the LED emission by some sunglasses caused by a notch-filter in the lenses of some types of sunglasses. The notch-filter frames out a very narrow band of radiation in the 580-600 nanometer (nm) range. This is the range at which amber LEDs emit. Amber LED-generated messages have a narrow emission spectrum which peaks at about 590 nm. Figure 4 shows that certain types of sunglasses on the market almost completely filter out light from almost exactly the same portion of the spectrum as the light emitted by amber LEDs. This plot is a reproduction of two separate plots created from tests performed by FHWA researchers (21). By reducing the relative brightness of the LED emissions, much more than that of the background surrounding it, the contrast seen between the LED message and the surroundings is decreased to a point where it is difficult to distinguish the message.
Sunglasses currently on the market appear to meet with current (1986) American National Standards Institute (ANSI) standards. ANSI apparently is considering the modification of the standard related to allowable filters used on sunglasses. Because LEDs are becoming commonly used in traffic control devices and for other automotive applications, these revised standards must consider the use of narrow-band sources and should not allow notch filters. The FHWA feels that there is an urgent need to bring this problem to ANSI’s and others’ attention.
Authority for Speed Control
The use of PVMSs to change motorist speed at and around work zones is reported to be effective by half of the agencies participating in the survey but typically they only reduce speeds by 5 mph, hardly a dramatic impact. This speed reduction seems to desist if signs are displayed for extended periods of time (5). One agency using the signs for speed control stated that this practice was effective only when police were present. Police presence alone may have this same effect, therefore speed control does not seem to be an effective use of PVMSs other than simply to draw attention to static regulatory signs used to alter work zone speeds.
PVMSs for Marking Lane Changes
Overuse of PVMSs for lane shifts or lane closures is another problem which was identified through reviewing surveys and comparing practices to recommendations found in reports (7). All of the reporting agencies use PVMSs to advise motorists of lane shifts or lane closures. This is a
C-14 Sunglass Filtering of LED Emissions 1.1
1 0.9 Company X's Sugnlass Lenses
0.8 CompanyY's Amber LED 0.7
0.6
0.5 0.4 Irradiance 0.3 0.2 Spectral Transmittance / 0.1 0
-0.1 500 520 540 560 574 586 600 610 640 680 720 Wavelength (nm)
Figure 4. Sunglasses Filtering of LED Emissions.
valid use of PVMSs but the frequency of their use for this purpose suggests that PVMSs are possibly over-used for this purpose, as some of the reporting agencies actually use arrows (<<<<<) displayed on their PVMSs. Arrow displays are not PVMSs, but they are arguably the best device for informing motorists of either right or left lane closures (6). PVMSs should never be used in place of arrow displays, but in some situations a PVMS may be needed to supplement the use of arrow displays (6).
Use of a Message to Alert Motorists to Future Changes in Conditions
Survey responses show that when PVMSs are used to alert motorists of future changes in current traffic and roadway conditions, the signs are typically placed some time prior to the date work begins. This is done so that motorists can change their travel patterns, thus lessening impacts when roadwork begins. One danger of leaving a message of this type displayed for very long is that motorists may ignore the sign, not noticing when the message is changed. If signs display the same message for extended periods of time, familiar motorists grow accustomed to the situation after a period of time and begin to ignore the signs. This becomes a problem when the message is later changed, as these familiar motorists may not notice the new message(1).
C-15 Displaying Default Messages
The problem with displaying default messages is similar to the previous problem. Some agencies feel that PVMSs should display messages at all times. In order to avoid using blank signs, some agencies revert to a default message. This message will typically provide information regarding conditions on other roadways, information about future roadwork to take place, or could simply state that normal traffic conditions exist.
Other researchers who have studied the use of these signs, stipulate that messages should be displayed only when unusual conditions are presented and if traffic and work zone conditions are known (1,2). Display of trivial information can lead motorists to ignore the signs, possibly missing important information when it is later displayed. Providing misinformation can lead to a lack of motorist confidence in the system. If all information displayed on the signs is important and accurate, motorists will associate value with information provided through PVMSs, and will be more likely to take actions based on the information.
Operator Boredom
Operator boredom is a potential problem with operating PVMSs from a traffic management center (TMC) (2). Many agencies, operating PVMSs, establish lists of pre-approved messages and leave the task of choosing and displaying the appropriate message to technicians, who often are not properly trained. Most of the time this person is not actively dealing with the signs, but is waiting for conditions to change. Boredom can easily occur and can lead to failure of the operator to display an appropriate message promptly when conditions change.
Outdated or High Maintenance Equipment
Lamp and equipment failures, as well as equipment maintenance needs can impede the effective operation of the signs, and require additional time and money (8). Outdated or high maintenance equipment can be very costly to operate. Diesel powered signs require much more maintenance than do newer solar powered signs, and incandescent lighting needs to be replaced much more frequently than LEDs. Signs that can only be operated from local controls, rather than remotely, require persons to drive to all signs in order to modify messages.
Cost and Manpower Necessary to Operate System
Agencies responding to the survey reported that a major impediment to the effective operation of their PVMS system is the large number of people needed to operate the system properly and the cost associated with employing these people. Lack of manpower was reported to limit the timely updating of messages which is necessary to maintain motorist confidence in the system. This is a problem of particular importance with remotely located signs, as it is very time consuming and costly to have operators constantly on site to monitor both sign display and site conditions, or to drive back and forth checking on these conditions. If a person is not able to be constantly on site, then messages are not kept as up-to-date and accurate as they should be. Under remote conditions, consideration should be given to not using PVMSs. Through poor operation of PVMSs at remote
C-16 locations, drivers may be subjected to information they see as useless or non-productive. This can lead to a loss of faith in the system, and ultimately to the ineffectiveness of PVMSs.
Motorist Recognition of Abbreviations and Symbols.
Reporting agencies all use abbreviations in their messages, but these abbreviations are usually reserved as a last resort. They are typically used to display words of more than eight characters or if necessary to aid in fitting a message onto either one or two frames when additional frames would otherwise be necessary to display critical information. Two reporting agencies currently use symbols for displaying messages, but this is a relatively new idea and can only be performed with new PVMSs having these capabilities.
Problems occur when abbreviations or symbols used are not easily recognizable. A list of commonly understood abbreviations was published in 1981 (6) and has not been updated since. This list of abbreviations (4,20) both understood, and not understood, may not reflect motorist understanding of abbreviations today as well as it did then. Symbols have more potential for problems with motorist understanding, as most motorists are not as familiar with symbols.
C-17 RECOMMENDATIONS
Commitment to System
Manpower
The effective use of PVMSs requires a significant investments in personnel and equipment. The key to operating a PVMS system effectively is to keep the motorists’ faith in the system. This requires careful attention must be given to making sure that the messages displayed are kept accurate, up-to-date, and reliable. Monetary constraints and lack of qualified personnel can greatly affect design and operation of the signing system (2), as messages displayed are influenced by the quality of information received about conditions in the field.
Since drive-by checking of message accuracy is the most common method, enough personnel need to be involved, with operations, to check on all displays. To meet this need for personnel in the field, it would be beneficial for operating agencies to work with personnel outside of their agency, such as police and contractors, who are typically stationed near the displays. Many agencies use contractors to some extent. This would be a good place to shift some responsibility at least for keeping operators informed of work zone conditions.
The author recommends working more closely with police to obtain information on traffic conditions and to monitor message displays, as police are typically patrolling these areas anyway. Also traffic reporters who are already reporting on conditions could possibly be contracted for this purpose at a lesser price than using agency personnel. This better use of human resources, along with the equipping of all signs with modems, would greatly reduce the problems associated with personnel and operating expenses.
Equipment
Technology is always continuing to improve in areas related to advanced signing. It is important for operating agencies to be aware of available technology. Currently, amber LED displays are being investigated due to their being filtered by some sunglasses. However, some LED devices are available that do not emit light in the same portion of the spectrum as do those being filtered. Ontario has used LED displays with clustered red and yellow LEDs to get the result of an amber display (1). This is a possible remedy for light filtering by sunglasses.
The problem that some agencies have had with cloning of cellular frequencies is remedied by use of one-way calling, but this does not allow for sign monitoring and thus still requires that someone verify messages visually. A new cellular service is available in some areas, referred to as Cellular Digital Packet Data and is commonly known as CDPD. This technology keeps a direct link open between two points, but users are only charged when messages are being transmitted. This should be explored as a possible solution to the cellular problems.
Solar powered signs should be used when possible due to their low maintenance (8), as well as the advantages they have over diesel powered signs regarding environmental issues such as noise
C-18 and air pollution. Use of these signs may not be best suited for areas with severe winter conditions, as snow and ice can lead to operational problems. However, little freeway maintenance and construction work occurs in winter.
Additional measures to improve efficiency of a system are to key all signs the same so that the various personnel who need to access the signs can do so with ease, and to use uniform hitches for all trailer mounted displays and towing vehicles.
Guidelines and Standards
Operator’s Manual
PVMSs are operated by a variety of individuals with various expertise. These sign operators need to control the messages put on PVMSs, as traffic conditions vary too much for a pre-determined list of messages to fit every circumstance (6) and because many operating agencies do not use pre- approved messages. All agencies operating PVMSs should adopt an operator’s manual that can be used as a quick reference tool.
The Manual should include guidelines on all aspects of operating the signs, from deciding if a PVMS is the appropriate method of signing, to creating the messages to be displayed (21). It should also emphasize the importance of using static signing, as primary signing, and/or HAR in conjunction with PVMSs (6). The manual adopted by an agency should be designed for the most common signs used. This is typically a sign with the ability to display eight characters per line and having three lines. This should be a living document, evolving as the use of PVMSs does.
Some important details that should be discussed and presented in the manual would include where, when, and how a PVMS is to be used, along with messages to be displayed and guidelines for creating messages. The latter is important because pre-approved messages designed for common situations are an important part of the manual, but hardly fit every situation. Another helpful item to include could be lists of abbreviations to use and not to use, based on motorists’ abilities to understand them (4,20).
Training
Generally department of transportation employees, private contractors, and police are required to make judgments on when, where, and how to use PVMSs with little training or guidance. To remedy this problem, training courses should be provided. PVMS operators should be trained to make necessary decisions about using the signs and should have guidance in doing so. As stated previously, operator’s manuals should be adopted by agencies to be used as a quick reference. Steps should be taken to assure that individuals involved in operating signs are familiar with the manual; each operator should be provided a personal copy so that notes can be made in the manual. Other tools that ideally should be a part of the training process are training videos, and possibly some type of software interface (22). Training videos could be kept as refreshers to be viewed periodically and software interfaces would aid in everyday operation.
C-19 Message Guidelines
Shortening Messages
Messages should be short enough that motorists have time to read them. This message length is governed by traffic speeds. There is only time to relay a very limited amount of information to motorists, especially with the higher freeway speeds being implemented now. Therefore, unnecessary information should be avoided along with implied information and only the basics should be displayed. Real-time messages must convey a condition and an action to the motorist (2) and this is all that there is usually time or need to display.
The exposure time plots, Figures 2, 3, and 4, were developed as a tool for determining the amount of time a motorist has to view a message. When these plots are used in conjunction with the minimum reading and message exposure times for short word messages plot, Figure 5, from the Manual on Real-Time Motorist Information Displays (2), a person can determine the maximum number of words that should be displayed in a message for the given conditions. Exposure time must always be greater than the critical reading time of the message selected to be displayed.
Figure 5. Minimum Reading and Message Exposure Times for Short Word Messages (2).
C-20 Messages are most effective when presented as a single frame. If this is not possible, a maximum of two frames should be used, and the message displayed on each frame should not be confusing or misleading if standing alone (23). Abbreviations are typically used to aid in fitting a message onto either one or two frames when additional frames would otherwise be necessary to display critical information.
Other Guidelines
Often a message is too long either to be displayed on a single sign frame or to be read during the time period a single sign is legible to a motorist. This requires that a message be displayed in parts, either by sequencing the message on a single sign or by displaying the message on two successive signs. Repetition is a good tool to use for this purpose if space permits, as repetition of a key term not only reinforces that term, but also makes motorists aware of the connection between messages displayed on separate signs (2). Repetition can also be used to avoid the display of a single word in a two frame sequence.
Multiple frame messages should be composed of single frame messages that have the ability to stand alone (7). This way if the two information elements are simply read in alternate order, there will be no problem with motorists understanding the meaning of the entire message. When preparing multiple frame messages, no more than two displays should be used within any one cycle, and messages should not scroll on the frame (3).
There are two recommended methods for positively separating successive repetitions of a message being displayed. The method preferred by experts, in the area of Real-Time motorist information devices, is to display a row of asterisks for ½ second at the end of the message (2). An alternative is to display a blank frame for 1 second at the end of the message.
Signing Techniques
PVMSs should not be used in place of static signs. Static signs should be considered as the primary signing measure, and PVMSs should only be used in conditions where it is determined that static signs alone can not provide the necessary information (6). This is important to remember when marking a lane shift or lane closure as these signs should not be used in place of arrow displays where an arrow display could adequately perform the task at hand. Because PVMSs relay very limited amounts of information to motorists, they are most effective when used in conjunction with static signing or HAR, especially for tasks such as detour routing which may require communication of complex information.
When using PVMSs in conjunction with static signs, they typically should be positioned in advance of any other temporary traffic control zone signing but should not replace any required signing (3). When these two signing methods are used together, some attempt should be made to have motorists see the messages provided through these different devices as having relevancy to each other. It would be beneficial, when ideas are repeated, to use the same key words on each devices. For instance, if the static signs being used to direct traffic at a work zone read USE ALTERNATE ROUTES, then PVMSs used to supplement this signing should also read USE ALTERNATE ROUTES, or use the word “ALTERNATE”, and not USE OTHER ROUTES.
C-21 For control of work zone speed changes, static signing is necessary if the speed is to be enforced. If PVMSs are used for this purpose, they should be used to draw attention to the speed change which must then be signed with a regulatory sign.
A PVMS is a tool for gaining the motorist’s attention, and it should only be used if there is a specific message that needs to be conveyed to motorists. Overuse of these signs reduces their effectiveness. When there are no unusual conditions to report PVMSs should be left blank, or removed from the clear zone and stored out of view (1).
Sign design and placement criteria can be developed to meet message legibility requirements. This process can be aided by the aforementioned Figures 1,2,3, and 5. If the 85th percentile speed of a roadway is known, then the plots can be used to determine how long the message can be, and how close to the road the message should be placed if motorist legibility requirements are to be met.
Procedures for Personnel
Some methods which can avoid operator boredom, when PVMSs are operated from a TMC, are discussed in the Manual on Real-Time Motorist Information Displays (2). A higher level of personnel could perform the duty of changing messages, and at the same time evaluate or upgrade and operate the system, and these people could alternate duties so as not to become bored. A third approach is to assign the personnel in charge of operating the signs with additional duties relating to roadway operations. Often the best way to keep the operator from becoming bored is to keep him or her busy performing other related tasks. This could best be done using higher level personnel, qualified to perform various other duties associated with transportation management centers or operational headquarters.
Another approach is to gather as much feedback as possible from the different personnel involved with the PVMSs, about their ideas for better managing the signs, and better training and operating procedures that could be adopted. These are the people who deal with the issues each day and who, more than likely, have an opinion on the methods being used, and on other methods they would like to see tried.
Amend Policy or Legislation
When techniques seem to be working well, but policy is limiting the use of that technique or technology, sometimes the best solution is to proceed with the practice and at the same time attempt to change policy. This may be the best approach to take with the LED filtering issue. LED technology has numerous advantages over other lighting and display techniques, not only for use on PVMSs but also in traffic signals and on other roadway devices. It may be better to alert the public of the adverse effects of wearing certain types of sunglasses, while attempting to change the policy as to the filters which sunglass manufacturers are allowed to use for filtering light, than to limit the use of LED technology in traffic control devices.
Additional guidelines and standards need to be introduced into the MUTCD. There is no official policy, or legislation restricting how messages shall be displayed. Policy needs to be clear
C-22 about the time for which messages shall be displayed. The MUTCD currently states that messages displayed on PVMSs should be readable at least twice at the posted speed limit. This often is not feasible at freeway speeds for any messages composed of more than a single frame. Furthemore, this is in many cases not feasible, even for single frame messages, as displays can be blocked by other traffic. Due to a severe lack of conformity to this policy, or need to conform to it, it should be omitted from future printings of the MUTCD.
System Evaluation
Agencies operating PVMSs should have some procedure for evaluating PVMS systems. This may be a difficult task to perform, especially if it is to be performed by the same agency responsible for operations. It may be most beneficial to contract such an evaluation to an outside consultant, to assure objective evaluation.
This process should look at many aspects of operations, and could possibly use the impediments outlined in this report as a basis for such evaluation. It would likely prove beneficial to talk with the different levels of personnel involved in operations, both individually and as groups, to get their feelings on what problems exist and to develop some ideas for improvements that could be made. This could be a desirable first step to take when performing an evaluation of such a system. Ideas for Future Research
Some areas of PVMS operation and message design that need further study are listed below:
C Motorist recognition and interpretation of symbols used on PVMSs; C Reevaluation of motorist understanding of the numerous abbreviations typically used, and not used on PVMSs; C Design and legibility of messages using a combination of upper and lower case lettering; and C A study of training programs operated by different agencies to train PVMS operators.
C-23 EVALUATION OF THE VIRGINIA MANUAL (4)
The Virginia Transportation Research Council has compiled a guide for developing a PVMS operator’s manual (6), and also wrote a manual (4) and a handbook (22). These items are currently used by several states (3 of the 7 responding to the survey), and are helpful guides for operating PVMSs. However, they do not include recommendations for overcoming all impediments. This section of the report discusses the Portable VMS Operator’s Manual (4), noting its utility, strengths, and areas for improvement to enhance the scope of its usefulness.
Strengths
The manual is designed as a tool to be used for two main objectives, the training of both public and private sector personnel, and as a reference manual for those personnel to use in operating the signs. The beginning of the manual contains a very important statement, enhancing its credibility. It states in bold print “Indeed, it is better not to use a VMS at all than to use one incorrectly.” This idea is then reinforced in the procedures to be followed when operating the signs; two preliminary checks for determining if a PVMS should be used are as follows: 1) that the message accuracy can be confirmed from a reliable source , and 2) that traffic conditions may be monitored to detect significant changes so that the signs may be removed or messages may be modified as events warrant.
The manual addresses the problems associated with prolonged use of a message, and states that static signing should be used rather than PVMSs for these situations.
A very important feature of the manual is the heavy emphasis it places on message brevity, content, and display, in fact 12 of the 17 modules covered in the manual relate directly to these message topics. The manual provides sample messages for themes common to many messages typically displayed, along with portions of messages to aid in message design. It also provides a list of recommended abbreviations, so that sign operators will have a quick, easy, method of selecting only those abbreviations that are easily understood, to be displayed on the PVMSs.
One very important final step to the procedures for positioning and displaying a message, as outlined in the manual, takes place once the positioning and displaying are presumably complete. The manual calls for operators to perform a drive by test of the sign before leaving the site to verify:
C That the sign is plainly visible, even to an unexpecting motorist; C The frame display time is set at a desirable speed; C There is enough time to read, comprehend, and react to the message; C Essential information is displayed; C The sign is placed out of the emergency traffic flow-way; and C The message will continue to be accurate and necessary until an operator can adjust it.
C-24 Areas for Improvement
As stated previously in the report, the issues of manpower and cost associated with operating PVMSs at remote locations are extensive. Though it recognizes the need for personnel to be available to monitor both sign displays and site conditions, the manual does not offer insight on how to best provide this service given the limited monetary and human resources afforded by operating agencies. This issue could be addressed in the manual, as it has been in the recommendations section of this report.
The manual provides tables, formulas and sample calculations to be followed in determining the time motorists will be exposed to posted messages, for use in determining the maximum length of messages which should be displayed. However, this is a long and tedious process to be followed each time a message is posted at a new location. A useful tool to incorporate with such a manual would be exposure time plots, such as those in Figures 1, 2, and 3. These plots provide a quick reference for exposure time rather than having to follow a list of calculations, the procedure currently used by many operators’ manuals. When these plots are used in conjunction with the minimum reading and message exposure times for short word messages plot (2), Figure 5, operators can quickly determine limits as to the size of the messages that should be displayed.
Another important issue that a manual of this type should address is that of system evaluation. There should be a method for reviewing a system, determining what is working and what needs to be improved. This would be a challenging procedure to develop, but could prove very beneficial. This topic is discussed briefly in the recommendations section of this report.
C-25 ACKNOWLEDGMENTS
I thank God, through whom all things are possible.
This paper was prepared for a graduate course in transportation engineering, Advanced Surface Transportation Systems, at Texas A&M University. The author acknowledges those who dedicated time to making this program successful: Dr. Conrad L. Dudek the instructor who organized the course with the assistance of Ms. Sandra Mantey, and the professional mentors, Tom Werner, Walter Dunn, Les Jacobson, Colin Rayman, Jack Kay, and Ginger Gherardi. Their assistance throughout the summer truly enhanced the program.
A special thanks to Mr. Tom Werner and Mr. Walter Dunn for serving as my mentors for this study. They helped me to gain direction and focus in my approach and made themselves readily available to me throughout the summer.
I also thank the following people for taking the time and effort to complete my survey and/or for providing me with valuable reference materials:
Tom Batz and Sanjay Patel, TRANSCOM James Borden and Richard Ryan, California Department of Transportation David Rush, Virginia Department of Transportation Steve Cyra and Marc Hustad, HNTB Corporation M. Wayne Jones, Texas Department of Transportation, Houston District Thomas Kochanski and Walter Hoffman, Wisconsin Department of Transportation Peter Korpal, Ontario Ministry of Transportation Michael Madden and Roger Steinert, Washington State Department of Transportation Jan Meilhede and Mark Pyskadlo, New York State Department of Transportation John Paniagua, Texas Department of Transportation (TRANSGUIDE) Emilio Sosa, New York State Department of Transportation (INFORM) Peter Snyder, New York State Department of Transportation
C-26 REFERENCES
1. Dudek, C.L. Guidelines on the Use and Operations of Changeable Message Signs. Texas Transportation Institute. Report No. FHWA/TX-92/1232-9. June 1992.
2. Dudek, C. L. and R. D. Huchingson. Manual on Real-Time Motorist Information Displays. Report No. FHWA-IP-86-16. August 1986.
3. Manual on Uniform Traffic Control Devices (MUTCD). Part VI: Standards and Guides for Traffic Controls for Street and Highway Construction, Maintenance, Utility, and Incident Management Operations, 1988 edition, revision 3, September 3, 1993.
4. Virginia Department of Transportation. 1995. Portable VMS Operator’s Manual. Unpublished Draft.
5. Dudek C. L. and S.H. Richards. Catalog of Traffic Control Strategies and Devices. Texas Transportation Institute. Report No. FHWA/TX-86/58+321-1. February 1986.
6. Miller, J. S., B.L. Smith, B.R. Newman, M.J. Demetsky. Development of Manuals for the Effective Use of Variable Message Signs. Final Report. Virginia Transportation Research Council. Report No. VTRC 95-R15.
7. Dudek, C. L. Portable Changeable Message Signs at Work Zones. Texas Transportation Institute. Report No. FHWA/TX-85/07+292-4. July 1984.
8. Meilhede, J. New York State Department of Transportation. Survey conducted July 2, 1996.
9. Rush, D.B. Work Zone Safety Coordinator, Virginia Department of Transportation. Survey conducted June 28, 1996.
10. Madden, M. Washington State Department of Transportation, NW Region. Survey conducted July 3, 1996.
11. Smith, M.J. New Jersey Department of Transportation, Traffic Operations-North. Survey conducted July 3, 1996.
12. Jones, M.W. Director of Transportation Operations, Houston District. Survey conducted July 11, 1996.
13. Paniagua, J.J. Senior Operator, Texas Department of Transportation, Transguide. Survey conducted June 28, 1996.
14. Korpal, P. Ontario Ministry of Transportation. Survey conducted July 12, 1996.
C-27 15. Ryan, R. Acting Chief, Office of Signs, Delineation and Technical Support, California Department of Transportation. Survey conducted July 19, 1996.
16. Kochanski, T.R. Wisconsin Department of Transportation, District 2. Survey conducted July 15, 1996.
17. Sosa, E.C. INFORM Operations Director, New York State Department of Transportation. Survey conducted July 23, 1996.
18. Messer, C.J., W. R. Stockton, and J. M. Mounce. Human Factors Requirements for Real-Time Motorist Information Displays, Vol. 9—A Study of Physical Design Requirements for Motorist Information Matrix Signs. Texas Transportation Institute. Report No. FHWA-RD-78-13. February 1978.
19. Draft Guidelines for Variable Message Sign Use, Washington State Department of Transportation. May 1996.
20. FHWA. Letter to Tom Werner—Director of Traffic Engineering & Safety Division, New York Department of Transportation, regarding current revision of ANSI Z80.3-199X American National Standard of Ophthalmics- “Nonprescription Sunglasses and Fashion Eyewear- Requirements”. FHWA:HSR-30:Stignor:ca:285-2033:6-4-96, June 1996.
21. New York State Department of Transportation. Policy and Guidelines for the use of Variable Message Signs(VMS) Final Draft.
22. Virginia Transportation Technology Center. Using Portable Variable Message Signs, Participants’ Handbook. June 1995.
23. Traffic Operations Center Outline of Signing Policy for Variable Message Signs. Wisconsin Department of Transportation.
C-28 APPENDIX
SURVEY
USE OF PORTABLE VARIABLE MESSAGE SIGNS IN CONSTRUCTION AND MAINTENANCE WORK ZONES (Please check appropriate box or answer question, elaborating where appropriate)
1. Name______Title______
2. Agency______Section______
3. What applications are portable variable message signs used for by your agency, as related to work zones? (check all applicable)
‚ Maintenance ‚ Construction ‚ Incidents ‚ Special Events ‚ Change Travel Speed ‚ Shift Lanes ‚ Close Lanes ‚ Divert to Different Route ‚ Make Motorists Aware of Future Change to Current Traffic Conditions ‚ Reference Highway Advisory Radio ‚ Other?______
C-29 4. What messages are used for each of these different applications checked above? • Change Travel Speed
• Change Lanes
•Close Lanes
• Divert to Different Route
• Make Motorists Aware of Change to Current Traffic Conditions
• Reference Highway Advisory Radio
•Other
5. Does the use of the signs for each of these applications seem to be effective? • Change Travel Speed YES NO • Change Lanes YES NO •Close Lanes YES NO • Divert to Different Route YES NO • Make Motorists Aware of Change to Current Traffic Conditions YES NO • Reference Highway Advisory Radio YES NO • Other?______
6. What standard default message is used, if any?______
C-30 7. Are Abbreviations used in messages? YES NO
8. Are Graphics/Symbols used? YES NO
9. Are 1 or 3 panel/line signs used? ‚ 1 panel ‚ 3 panel ‚ Both
10. Are single or multiple frame(frame being the visible portion of the message, 1 or 3 lines) messages used primarily? ‚ Single ‚ Multiple
11. When multiple frame (frame being the visible portion of the message, 1 or 3 lines) messages are used, how long is each frame displayed? ‚ 1 second ‚ 2 seconds ‚ 3 seconds ‚ Other______
12. What is the maximum number of frames used for a message? ‚ 1 frame ‚ 2 frames ‚ 3 frames ‚ Other______
13. Are all UPPERCASE letters used for messages?
YES NO
14. How many characters can be displayed per line on the signs? ‚ 6 characters ‚ 7 characters ‚ 8 characters ‚ Other______
C-31 15. What is the size of characters used on the signs? 18in. <18in. >18 in. If you did not answer 18in, please list height ______in.
16. How often are these messages updated? ______
17. Why are they changed when they are, or updated at the rate that they are? (please elaborate on procedure)
18. Who operates the signs? (mark all applicable) ‚ DOT (Traffic) ‚ DOT (Construction EIC) ‚ DOT (Maintenance) ‚ DOT (Traffic Operations Center) ‚ Contractor ‚ Police ‚ Other______
19. Are messages selected from a pre approved listing? YES NO
20. Where are the signs operated from? ‚ Mobile Unit ‚ Work Zone ‚ Office ‚ Traffic Management Center ‚ Other______
21. How are they controlled? ‚ Cellular call-in ‚ Control box at the sign ‚ Other______
22. What checks are made, if any, to confirm if proper messages are being displayed? ‚ Drive-by checks ‚ None ‚ Other (please elaborate)______
C-32 23. What problems are encountered in operating signs and in keeping messages current?
24. Please send me a copy of traffic control plans that your agency has for the use of these portable variable message signs. It would be much appreciated.
25. Phone number and convenient time where you can be reached for questions regarding answers to the survey. ( ) .
26. Address where compendium of Papers can be sent to you. (Please send or FAX a business card with survey, if available)
C-33 David M. Halloin received his B.S. in Civil Engineering from Michigan State University in December,1995. He is currently pursuing his M.S. in Civil Engineering at Texas A&M University, in the area of transportation, while working at the Texas Transportation Institute as a graduate research assistant. David participated in the Undergraduate Transportation Engineering Fellows Program at Texas A&M during the summer of 1995, when he was employed as a research aide for the System Implementation Program at the Texas Transportation Institute. He is a student member of the Institute of Transportation Engineers, the American Society of Civil Engineers, the National Society of Professional Engineers, and a member of the Order of the Engineer. His areas of interest include traffic management, geometric design, and traffic operations.
C-34 ELECTRONIC TOLL COLLECTION INFORMATION: IS PERSONAL PRIVACY PROTECTED?
by
Douglas J. Holdener
Professional Mentors Colin A. Rayman, P.E. Ontario Ministry of Transportation
and
Ginger Gherardi Ventura County Transportation Commission
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, TX
August 1996 SUMMARY
Electronic toll collection (ETC) systems offer travelers a convenient service. Vehicles do not need to stop for drivers to deposit a cash or token toll payment. Instead, tolls are debited electronically from the driver’s ETC system account balance as the vehicle travels through the toll plaza without stopping. Electronic toll collection provides a convenient service, reduces delay at toll plazas, decreases fuel consumption, and improves air quality, however, ETC users’ privacies may be compromised.
ETC agencies maintain accounts for all ETC system users. These accounts contain personal, vehicular, and financial information supplied by the user upon application to use the system. In addition, these accounts contain transaction histories, which may be interpreted as travel histories. This information is used billing and auditing purposes and is maintained for at least as long as the user holds an account with the ETC agency. However, the information may be used for secondary purposes, such as for law enforcement, judicial prosecution, or strategic marketing.
Privacy advocates have expressed concerns regarding the maintenance of ETC user information and the possibility of privacy invasions. This research document discusses several concerns from various privacy advocates in addition to presenting several privacy protection mechanism which may affect electronic toll collection systems. These mechanisms are available through US privacy laws and ETC agency policies. A literature review was conducted to determine US privacy laws, and a telephone survey was conducted with seven toll agencies utilizing electronic toll collection. An assessment of these mechanisms was offered, and applications for ETC agencies and ITS America which may improve personal privacy protection were suggested.
Based on the research findings, ETC agencies recognized the importance of addressing privacy issues, and they have methods for protecting privacy. Each agency reported to have security measures that protect against wrongful access to information. Most agencies reported that they do not disclose information to outside parties except law agencies and judicial entities. No agency reported that it allowed law agencies to monitor for traffic law violations or conduct surveillance on motorists. However, aspects of ETC agency policies may be improved to provide more effective personal privacy protection. Additionally, US privacy laws offer weak protection of ETC users’ personal privacy, and it is difficult to interpret if the studied laws apply to electronic toll collection.
Applications are recommended which may improve the quality of privacy protection within ETC systems. Applications are suggested for ETC agencies to further develop their privacy policies and for ITS America to provide leadership in reforming US privacy laws and supporting ETC agency effort to provide effective personal privacy protection.
D-ii TABLE OF CONTENTS
INTRODUCTION ...... D-1 Problem Statement ...... D-1 Objective ...... D-1
STUDY DESIGN ...... D-2
BACKGROUND ...... D-3 Electronic Toll Collection ...... D-3 Electronic Toll Transactions ...... D-3 Transportation Technology and Privacy ...... D-4 Defining Privacy ...... D-4 Privacy and Electronic Toll Collection ...... D-5
PRIVACY CONCERNS ...... D-6 Information Collection and Maintenance ...... D-6 Secondary Information Usage ...... D-6 Law Enforcement ...... D-6 Security ...... D-7 Personal Preference ...... D-7 Policy Standards ...... D-7
PRIVACY LAWS AND INDUSTRY GUIDELINES ...... D-8 The Privacy Act of 1974 ...... D-8 Freedom of Information Act, Exemption Six ...... D-8 Electronic Communications Privacy Act ...... D-9 ITS America Privacy Principles ...... D-9
SURVEY RESULTS: ETC AGENCY POLICY ...... D-10 Information Collection and Maintenance ...... D-10 Secondary Use of Information ...... D-11 Security Measures ...... D-12 Personal Preference ...... D-12 Policy Documentation ...... D-13
RESEARCH SUMMARY ...... D-14 Privacy Concerns ...... D-14 Privacy Protection Mechanisms ...... D-14 US Supreme Court Case History ...... D-14 US Privacy Laws ...... D-14 ETC Agency Policies ...... D-15
RESEARCH FINDINGS ...... D-16
D-iii APPLICATION OF RESEARCH FINDINGS ...... D-18 ETC Agency Policy ...... D-18 Information Access ...... D-18 Information Disclosure ...... D-18 Policy Documentation ...... D-19 ITS America Leadership ...... D-19
ACKNOWLEDGMENTS ...... D-21
REFERENCES ...... D-22
APPENDIX ...... D-24
D-iv INTRODUCTION
Electronic toll collection (ETC) systems offer travelers a convenient service. Vehicles do not need to stop for drivers to deposit a cash or token toll payment. Vehicles within the ETC system experience less delay as tolls are debited electronically from the driver’s account balance. Electronic toll collection provides a convenient service, reduces delay at toll plazas, decreases fuel consumption, and improves air quality, however, ETC users’ privacies may be compromised.
Problem Statement
Many electronic toll collection (ETC) systems maintain user information, including personal, vehicular, financial, and toll transaction history information. For example, personal user information may be necessary for primary uses such as billing and payment services; toll transaction history information may be necessary for transaction verification and auditing and may be valuable for transportation planning. However, this information may be used for a variety of secondary uses such as strategic marketing, law enforcement, and judicial prosecution. It is uncertain whether privacy protection mechanism exist or if personal privacy is compromised.
Objective
The objective of this research initiative was to determine and assess mechanisms that protect personal privacy of ETC system users. Based on the assessment, insight was offered to maintain or improve the effectiveness of privacy protection in ETC systems.
D-1 STUDY DESIGN
A literature review was conducted to assess (I) privacy advocate groups’ concerns about electronic toll collection agencies’ user information management policies and (ii) US privacy laws, court decisions, and transportation industry guidelines that may affect electronic toll collection.
A telephone survey was administered to both public and private tollway and turnpike agencies that use electronic toll collection. The survey was based on privacy advocates’ concerns about ETC systems. Table 1 lists the electronic toll collection agencies that participated in the survey. For each agency Table 1 indicates the respective ETC system’s publicly recognized name, the roadway facility’s name, the facility’s location, whether the agency is publicly or privately operated, and the type of transponder technology used.
Table 1. Listing of Surveyed Agencies That Use ETC.
Tag Agency System Name Location Operation Technology California Private Orange Co., 91 Express Lanes Private Read/Write Transportation Company California Orlando-Orange Co. Orlando, E Pass Public Read/Write Expressway Authority Florida Illinois State Toll Highway Chicago, I-PASS Public Smart Authority Illinois Greater New Orleans New Orleans, TOLLTAG Private Read-only Expressway Commission Louisiana New York State Thruway Read-only E-Z Pass New York Public Authority Read/Write Oklahoma Turnpike PIKEPASS Oklahoma Public Read-only Authority Harris County Toll Road Houston, EZ Tag Public Read-only Authority Texas
An identical telephone survey was administered to each agency to determine their information management and privacy policies regarding: information collection and maintenance; information security measures; information disclosure; and formal privacy policy development. The survey questions are listed in the Appendix of this document.
D-2 BACKGROUND
Electronic Toll Collection
Across the United States electronic toll collection systems have been providing efficient travel through tollways and turnpikes. Vehicles equipped with electronic transponders, or tags, do not need to stop to pay tolls. Instead the electronic transponder communicates via radio frequency or microwave to a roadside computer. The tagged vehicle is identified as an electronic toll collection system user, and the toll amount is debited from the user’s account.
Electronic toll collection systems use automatic vehicle identification (AVI) technology for communicating between the tagged vehicles and a system computer. The in-vehicle equipment is the electronic transponder (tag), and it maintains the user’s identification (ID) number and other information, depending upon the type of tag technology. Roadside equipment consists of (1):
1. a transceiver to transmit and receive information to and from the tag; 2. a lane controller that monitors toll lane activities; and 3. a primary processing computer which accesses account information and processes transactions.
Three basic electronic transponder technologies exist: Type I, read-only tags; Type II, read/write tags; and Type III, “intelligent” tags (1,2). Read-only tags store few data, such as the user’s ID number, whereas read/write tags can maintain unique variable data, such as entry/exits points of the toll facility and account balance (3). Intelligent, or smart, tags are microprocessor- based and have much more memory than either Type I or Type II transponders; these tags have the ability to calculate tolls and maintain the user’s account (2).
The presence of the electronic transponder may be detected by a roadside sensor or antenna even when the tagged vehicle is traveling at a high speed. Field performance evaluations of AVI technology used for electronic toll collection purposes have indicated reliability within the range of 89.7 to 98.4 percent (3). While conventional toll collection methods have a reliability range of 93 to 98 percent, ETC is equally reliable and allows for more efficient processing of toll-paying vehicles which reduces fuel consumption, vehicular emissions, and driver frustration.
Automating the toll collection process can offer significant increases in toll plaza lane capacity. A study to estimate the average capacity of different toll plaza lane configurations was conducted by the Florida Turnpike, New Jersey Turnpike, and Dallas North Tollway. From this study, the average capacity of dedicated ETC lanes, or lanes which cater only to tagged vehicles, was reported at 1200 vehicles per hour (3). A manually operated lane allowed an average of 350 vehicles per hour, and an automatic, coin insertion, toll plaza lane allowed an average of 500 vehicles per hour.
Electronic Toll Transactions
ETC users are typically required to maintain a certain minimum balance in their ETC account with the responsible toll collection agency. When the tagged vehicle passes through the toll plaza,
D-3 a unique ID code is detected by the roadside computer; the ID numbers are associated with individual users’ accounts, or toll records (2). The necessary toll is debited from the user’s account. If the user’s account balance drops below the minimum balance the toll collection agency will either automatically replenish the account balance by charging the user’s credit card or notify the user to replenish the account balance with a cash or personal check payment. Users may be notified through the mail, by a smart tag liquid crystal display (LCD), or by an electronic message sign as they pass through the toll plaza. Users have the option of deciding the type of account balance replenishment method they prefer; certain toll collection agencies allow only cash or check replenishment.
In order to maintain the integrity of the ETC system, a toll collection agency must maintain user accounts in a centralized system. These accounts are identifiable by the users’ personal and vehicular information, and the accounts allow the agency to accurately debit tolls from their users and conduct audits. The commonly-used Type I and II transponder technologies do not have sufficient on-board memory to conduct toll transactions or maintain user accounts, hence the necessity of a centralized account database (3).
Transportation Technology and Privacy
The transportation industry must constantly balance the demand for individual mobility with the greater societal demands. For example, signalized intersections are an attempt to accommodate the individual motorist traveling in a particular direction while simultaneously managing motorists traveling in opposing directions. Speed limits define a travel speed which balances the demand for expedient travel and an acceptable level of safety. ETC systems provide motorists with the convenience of increased mobility through toll plazas, however, motorists must directly disclose personal and vehicular information and indirectly disclose their travel history to the tollway operating agency that is required for system operation. Hence, an ETC system may provide its users with a convenient service while producing an information database of its users’ travel habits along the toll system.
The deployment of electronic toll collection systems may introduce a degree of intrusiveness which must be balanced with the benefits. It is important to investigate whether technological advancements in transportation, such as electronic toll collection, compromise individual privacy while improving the quality of travel (e.g. increasing mobility).
Defining Privacy
In 1966 Supreme Court Justice William O. Douglas recognized innovative technologies’ abilities to subject individuals to surveillance in Osborn v. United States, 385 U.S. 323, 341, and he stated “we are rapidly entering the age of no privacy, where everyone is open to surveillance at all times; where there are no secrets from government (4).” Prior to and since Justice Douglas’ statement, “privacy” was and has been defined numerous times by the US Supreme Court and by legal scholars, however, there is no universally accepted definition.
Justice Brandeis argued, in Olmstead v. United States, 277 U.S. 438, 478 (1928), that the right to be let alone, privacy, is our most valued entitlement (5). Some legal scholars have maintained that privacy is the claim of an individual, group, or institution to decide when, how, and
D-4 to what extent information about them may be communicated to others. This argument implies that any information that an individual, group, or institution does not want communicated is subject to an invasion of privacy. Hence, without a clear definition of the information boundaries subject to this definition, it may be difficult to determine when one’s privacy has been compromised. Privacy may also be thought of as the control of access to information. According to this definition, privacy and access are related, and privacy may simply be considered a limitation of access.
In the context of transportation, the Supreme Court has stated that a person has a lesser expectation of privacy in an automobile since its function is to transport and it rarely serves as a residence or repository of personal effects (6). In Cardwell v. Lewis, 417 U.S. 583, 590 (1974), the Court read that a vehicle has little ability to escape public scrutiny and that it travels public thoroughfares where it and its occupants are in plain view. In New York v. Class, 475 U.S. 106, 113 (1986), the Court stated that a vehicle identification number (VIN) plays an important role in pervasive government automobile regulations, and there is no reasonable expectation of privacy in the number, for Fourth Amendment purposes. Additionally, the surveillance of vehicles and drivers has not been found to violate an enforceable right to privacy. The Court, in United States v. Knotts, 460 U.S. 276 (1983), held that surveillance by law enforcement through a radio transmitter, or beeper, in the vehicle was equivalent to following the vehicle on the public streets; the defendant had no reasonable expectation of privacy in his movements through the public streets (6).
Regardless of an absence of a universal privacy definition, many feel that privacy is a fundamental right that allows us to live as we desire. A 1990 Harris Poll indicated that about 80 percent of respondents agreed that they would add “privacy” to the fundamental rights of “life, liberty, and the pursuit of happiness” in the Declaration of Independence (4). Interestingly, a survey of San Francisco Bay Area motorists indicated that only 7 percent of the respondents were strongly concerned that electronic tags could track their vehicle (3).
Privacy and Electronic Toll Collection
Electronic toll collection allows the collection of large amounts of personal travel history information. The potential exists for an electronic toll collection agency to know when and where users travel to and from, and some privacy advocates believe that an agency may be able to “predict when someone is or is not at home; where they work, spend leisure time, go to church, and shop; what schools their children attend; where friends and associates live; whether they have been to see a doctor; and whether they attend political rallies (7). This part of the privacy problem could be created if outside parties gain access to data collection information and that information is used for unintended purposes (6).
The deployment of electronic toll collection requires the creation of a database to maintain toll payment records and account balances, but may also contain other information, such as travel habits, that is easily accessible. This may result in an unprecedented invasion of privacy.
D-5 PRIVACY CONCERNS
A 1994 poll suggested that 84 percent of people in the U.S. were concerned about privacy (8). Included within those concerned about privacy issues are privacy advocates. Privacy advocates have examined electronic toll collection systems’ impact on personal privacy and have publicly expressed their concerns. Many privacy advocates’ opinions are expressed over the Internet.
This section provides an overview of several privacy issues concerning electronic toll collection systems. These are concerns raised by privacy advocates and are not intended to suppress the use of new technologies, but instead to assist development of technologies and policies that effectively address these privacy issues.
Information Collection and Maintenance
Electronic toll collection system users may be unaware of the type of information collected and maintained in their accounts or that someone is monitoring their activities (8). One issue which must be addressed is the necessity and usefulness of the collected information (6). If individually identifiable information is collected and maintained, this information could be used for unintended purposes (9, 10). An alternative would be a system that allowed users to remain anonymous. This anonymity, combined with minimal information collection and limited time for information retention would reduce potential for wrongful use.
Secondary Information Usage
Information maintained in ETC systems’ users’ accounts may be considered quite valuable for secondary uses. Detailed personal profiles of millions of persons may be created by predicting travel habits, origins, and destinations (8). It has been conceived that a wide variety of organizations and companies may propose secondary uses for the information as personal information databases grow (11). For instance, some credit card companies sell name and address listings of their cardholders that are grouped according to common purchases; phone companies, video stores, and some charities sell customer records (8). In a transportation context, this may result in highway-dependent businesses, such as gas stations and shopping centers, discovering the identities of highway commuters in order to direct their marketing campaigns. Other secondary uses might include employee surveillance, judicial prosecution, or law enforcement.
Law Enforcement
Since the ETC system can detect the precise time that a transaction was made in the toll plazas and there is a known distance between sequential plazas, the speed of a tagged vehicle may be determined rather simply by dividing distance by time. This may be a convenient method for law enforcement officials to enforce speed limits. Technological advancements can and should assist law enforcement efforts. However, concern is raised about enforcing traffic laws and employing motorist surveillance without ETC system users knowledge or consent (12).
D-6 Security
An important element of maintaining information privacy is ensuring that the information is secured from external access and internal leakage (9). Information may be accessed externally at the initial transmission between the tag and the toll plaza transceiver, or it may occur if the information database is networked. Internal access may be obtained by an electronic toll collection system employee. In recognizing the value of user information for certain secondary uses, security is seen as an important precaution to ensuring that information is not wrongfully used and personal privacy is not jeopardized.
Personal Preference
Electronic toll collection should not completely replace conventional toll collection methods of tokens or cash. ETC system users should have an informed choice to use the system based on the toll agency’s privacy policy which may inform users if account information is disclosed for secondary uses. Use of the electronic toll collection system should be voluntary to users and all motorists to traverse a roadway (9). ETC system users should also have the choice to replenish account balances with either credit, cash, or check.
Policy Standards
The adoption of technical standards has been viewed as a way to prevent the wrongful disclosure and secondary use of ETC system users’ account information. Some advocates observe the insecure protocols in the cellular telephone industry and fear that the electronic toll collection industry may also adopt insecure standards (9). Adopting secure standard policy will allow agencies greater ability to manage information and protect privacy interests.
D-7 PRIVACY LAWS AND INDUSTRY GUIDELINES
The concept of information privacy is not a fundamental Constitutional right, however, it has been upheld as a lesser Constitutional right. The Court has applied a balancing test to weigh the Government’s interest against the individual’s interest in nondisclosure of information, and often the state’s interests outweigh the individual’s interests. Legal protection of information privacy within the private sector must be provided by Federal or State laws, state common law, contractual agreement, or voluntary code. It is important to consider that voluntary codes, or industry self- regulations, do not create enforceable legal rights (6).
The Federal Highway Administration (FHWA) has recognized that electronic toll collection and other intelligent transportation systems may jeopardize privacy. Several studies have been conducted to address privacy issues before problems arise. In fact, the Intermodal Surface Transportation Efficiency Act, 23 U.S.C. 307, allowed the FHWA to provide a grant to the University of Santa Clara School of Law to study privacy and intelligent transportation systems (4).
This section will discuss several laws which govern privacy interests and may affect electronic toll collection policy and the Intelligent Transportation Society of America privacy guidelines for developers and operators of intelligent transportation systems, including ETC systems. In addition to the laws mentioned in this section, Congress has enacted several financial privacy statutes that may be relevant to electronic toll collection systems: the Fair Credit Reporting Act of 1970, 15 U.S.C. 1681-1681s; the Fair Credit Billing Act of 1974, 15 U.S.C. 1666; the Fair Debt Collection Practices Act of 1977, 15 U.S.C. 1692-1692o; and the Electronic Funds Transfer Act of 1978, 15 U.S.C. 1693-1693r.
The Privacy Act of 1974
The Privacy Act of 1974, 5 U.S.C. 552a, was created to protect personal information in the absence of a demonstrable and justified cause to intrude into someone’s life (4). This act is an omnibus code of fair information practices that attempts to regulate the collection, maintenance, use, and disclosure of personal information by federal government agencies (13). It applies to information maintained within the executive branch of the federal government, and it does not generally apply to records maintained by state and local governments, private companies, or private organizations (14). Only about one half of all states have statutes similar to the Federal Privacy Act which apply to state governmental entities collecting and maintaining personal information (7). The Federal Privacy Act will ensure personal information privacy of ETC systems to the extent that ETC system user information is in the custody of a Federal agency, such as the US Department of Transportation (DOT) or Federal Highway Administration (FHWA). However, since ETC systems are typically operated privately or through a state-level agency the Federal Privacy Act does not apply.
Freedom of Information Act, Exemption Six
The Freedom of Information Act (FOIA), 5 U.S.C. 552, entitles the public to access records in possession of agencies and departments in the executive branch of the US Government. FOIA does not apply to private companies or State or local governments, however, all states and some localities have passed laws similar to the FOIA (14).
D-8 The FOIA contains certain exemptions that protect executive branch records containing personal information. In the Federal FOIA the sixth exemption covers personnel, medical, and similar files which constitute an unwarranted invasion of personal privacy, however, it is unclear how the exemption may apply to ETC system account information. The exemption requires the agency to balance an individual’s privacy interests with the public’s right to know. While only a clearly unwarranted privacy invasion is a basis for withholding information, the exemption does make it more difficult to obtain information without consent (6).
Electronic Communications Privacy Act
The Electronic Communications Privacy Act (ECPA) of 1986, 18 U.S.C. 2510, provides civil and criminal penalties for unauthorized interception or disclosure of electronic communications (6). The act prohibits the interception of certain electronic communications, such as those from cellular telephones, pagers, or satellites. The ECPA does not apply to communication from a tracking device (6). A tracking device is an electronic or mechanical device which allows a person’s or object’s movement to be tracked. Hence, it does not appear that AVI communications, used for ETC, are subject to the ECPA.
ITS America Privacy Principles
The Intelligent Transportation Society of America has drafted the Intelligent Transportation Systems Fair Information and Privacy Principles in recognizing the importance of protecting the privacy of intelligent transportation system users. The principles are advisory and intended to assist transportation professionals and policy makers as they develop their own fair information and privacy guidelines for intelligent transportation system projects. ITS America urges intelligent transportation system operators to publish these guidelines once they have been established (15).
ITS America suggests that the following eight, summarized principles be followed by intelligent transportation system project designers and operators:
1. An ITS agency should recognize and respect individual interests in privacy and information use; 2. An ITS agency should allow the public to understand the type of data collected, how it is collected, what its uses are, and how it will be distributed; 3. An ITS agency should comply with state and federal privacy and information usage laws; 4. An ITS agency should maintain secure databases; 5. Without government authority, information should not be used for surveillance or law enforcement purposes; 6. Information systems should contain only information that is relevant for ITS purposes; 7. Only information absent of personal identifiers should be available for secondary use; information containing personal identifiers should be disclosed only with user’s consent and ability to refuse; and 8. Information systems should balance the individuals’ interests in privacy and the public’s right to know; public/private frameworks of data collectors should resolve access problems resulting from the FOIA.
D-9 SURVEY RESULTS: ETC AGENCY POLICY
This section discusses the type of information collected and the purpose it is collected for by the surveyed electronic toll collection agencies. It will also present an assessment of the surveyed agencies methods of addressing privacy concerns.
Information Collection and Maintenance
Each agency reported the need to collect and maintain information that is individually identifiable, such as name, driver’s license number, and vehicular information. Tables 2, 3, and 4 list the personal, vehicular, and financial information that is requested upon application to use the electronic toll collection system and is maintained in user account records by each of the surveyed toll agencies.
Each of the seven agencies requests basic personal information (Table 2), such as name, address, and telephone number. However, each agency does not necessarily request a driver’s license number or a social security number. Only one agency does not request vehicular information (Table 3), such as license tag number and state and vehicle make, model, color, and year.
Table 4 shows the type of payment information that is requested and maintained by the surveyed agencies. Each of the surveyed agencies requires the user to establish an account from which toll charges are deducted. When the account balance drops below a certain amount, a pre- specified amount may be deducted from a credit card or banking account, as preferred by the user. Each agency allows users to replenish accounts by personal check or cash directly to an agency representative; the I-PASS system requests that users replenish their accounts by cash or personal check only.
Table 2. Application Information Requests: Personal Information.
91 Express Request E Pass I-PASS TOLLTAG E-Z Pass PIKEPASS EZ Tag Lanes
Yes Name Yes Yes Yes Yes Yes Yes
Yes Address Yes Yes Yes Yes Yes Yes
Yes Phone No. Yes Yes Yes Yes Yes Yes
Driver’s No Yes Yes No No No Yes License No.
Social No No No No Yes Yes Yes Security No.
D-10 Table 3. Application Information Requests: Vehicular Information.
91 Express Request E Pass I-PASS TOLLTAG E-Z Pass PIKEPASS EZ Tag Lanes
LicenseTag Yes Yes Yes No Yes Yes Yes No./State
Make Yes Yes Yes No Yes Yes Yes
Model Yes Yes Yes No Yes Yes Yes
Color Yes Yes Yes No Yes Yes Yes
Year Yes Yes Yes No Yes Yes Yes
No. of No Yes Yes Yes No Yes No Axles
Table 4. Application Information Requests: Financial Information.
91 Express Request E Pass I-PASS TOLLTAG E-Z Pass PIKEPASS EZ Tag Lanes
Credit Optional Optional No Optional Optional Optional Optional Card No.
Bank Acct. Optional No Optional No No No Optional No.
In addition to this personal, vehicular, and financial information, each agency maintains transaction history information in a user’s account. Typically, the time, date, and location of each toll transaction is recorded for each ETC system user. Three agencies maintain accessible transaction history information for as long as the user maintained an account. Two agencies archive the transaction history information after three months, and one agency archives after three weeks. One agency reported that it maintains travel history and all account information for seven years beyond the termination of the account.
Secondary Use of Information
Five out of seven agencies reported that they had received requests for user account information. Requests were made by marketing analysts, curious spouses, or employers tracking employees.
Five of seven agencies indicated that they do not disclose any account information to parties other than a law enforcement agency or court of law. Of the other two agencies, one agency indicated that it discloses name and address information to outside-party requests, and another
D-11 agency indicated that it releases account information to other public and private electronic toll collection agencies in the area to be used for toll collection purposes only.
No agency reported that it allows law enforcement officials to monitor transaction records for traffic law violations. However, three agencies have cooperated with law enforcement for special requests, such as to provide information about a repeated tollway violator, car thief, transponder thief, or a police assault and battery suspect.
Security Measures
Each agency reported that security measures were in place to ensure information security. Table 5 lists reported security measures and the number of agencies, out of seven, that employ them. Each agency reported using at least one of the security measures listed in Table 5; several agencies reported that they practiced more than one security measure.
Table 5. Information Security Measures.
Security No. of Agencies Measure (out of 7) Limited Employee 5 Access to Accounts Supervisory 1 Control Employee 2 Screening
Five agencies reported that they limited account accessibility to only employees that had justifiable reasons for accessing information. One agency reported to supervise employees while they manage user accounts. Two agencies screen employees’ credit and criminal histories prior to hiring and allowing them to manage accounts.
Personal Preference
The use of the electronic toll collection system is optional to traverse the tollway for each agency except for the 91 Express Lanes system. The 91 Express Lanes is solely an electronic toll collection system and does not allow non-tagged vehicles to use the facility legally; car-poolers are exempt from paying to use the 91 Express Lanes, however, they must acquire and use the electronic transponder.
D-12 Each agency allows users to access their account information upon request, and users may terminate their account at any time. ETC system users may choose to have account balances replenished by a cash or check payment, a credit payment, or an automatic credit transaction.
Policy Documentation
Two agencies reported that they had documented guidelines for maintaining user account information to be used by agency employees only. None of the seven agencies indicated that they had publicly-available documented policies outlining their account information management practices. However, each agency did report to have general information on their respective electronic toll collection system and documented terms and agreements that each user agrees to upon account application. Furthermore, none of the agencies reported that they have ever consulted with the ITS America privacy principles; the inception of the ITS America privacy principles occurred recently and untimely with the deployment of the surveyed ETC systems.
D-13 RESEARCH SUMMARY
This research effort has determined various privacy advocates’ concerns about ETC systems protection of users’ personal privacy. It has also determined several mechanisms through US privacy laws and ETC agency policies that address privacy issues and may affect electronic toll collection. These findings are summarized in this section.
Privacy Concerns
The main concerns of the privacy advocates determined through this research may be summarized as:
C individually identifiable information is not necessary to maintain; C information may be used for secondary, perhaps wrongful, purposes; C information will be used for law enforcement and surveillance; C information security is inadequate or not provided; C motorists cannot exercise personal preference to use ETC system; and C ETC agency policies are insecure or nonexistent.
Privacy Protection Mechanisms
Several mechanism that may affect personal privacy in ETC systems were identified. These mechanisms may be found in US Supreme Court case history, US privacy laws, and ETC agency policies.
US Supreme Court Case History
The Court has ruled that motorists have little expectation of privacy in an automobile, since its transport is to transport, and it rarely serves as a residence or repository of personal effects. It has ruled that motorists in a vehicle have little ability to escape public scrutiny as they travel along public thoroughfares. In disputes between individuals and law enforcement concerning electronic surveillance, the Court has ruled that electronic surveillance is equivalent to following a vehicle along a public street. The majority of cases are decided in the favor of the State.
US Privacy Laws
Three US laws were examined through this research initiative: the Privacy Act of 1974; the Freedom of Information Act (FOIA), Exemption 6; and the Electronic Communications Privacy Act (ECPA). Both the Privacy Act and FOIA, Exemption 6 may prevent disclosure of personal information from federal executive branch agencies. About one half of all states have laws similar to the Federal Privacy Act, and all states have laws similar to the FOIA. It is difficult to interpret whether or not ETC account information is protected under these laws. The ECPA penalizes persons that intercept or disclose electronic communications without authorization. This law does not apply to vehicle tracking technologies which allow a person’s or object’s movements to be tracked.
D-14 ETC Agency Policies
Seven ETC agencies were surveyed to determine their policies to address privacy issues. Based on survey results, the following was summarized:
C agencies need to collect individually identifiable information for billing and auditing; C ETC system users supply all personal, vehicular, and financial information; C most agencies do not disclose information to outside parties; C agencies do not allow surveillance of motorists; C law enforcement may access account information under special circumstances; C agencies do employ security measures to protect account information; C most agencies allow users to choose ETC or conventional toll payment; C no agencies have created formal, publicly-available privacy policies; and C no agency has consulted with the ITS America privacy principles.
D-15 RESEARCH FINDINGS
Privacy advocates, the US government and the US DOT, ITS America, and ETC system agencies recognize the importance of offering convenient transportation services without jeopardizing personal privacy. Mechanism have been established through ETC system agency policies and US laws that may offer privacy protection to ETC system users. However, policies are not foolproof, and US laws are difficult to interpret and may not apply to electronic toll collection systems.
The three US laws studied, the Federal Privacy Act of 1974, the Freedom of Information Act (FOIA) Exemption 6, and the Electronic Communications Privacy Act (ECPA), offer weak privacy protection for ETC system users. The Federal Privacy Act applies only to federal executive branch agencies, such as the US DOT or FHWA. However, most ETC systems are operated on the state level, and this law does not apply. Furthermore, only about one half of states have adopted similar legislation. Under the Privacy Act, information disclosure is subject to a balancing test to weigh the privacy protection interests of the individual against the interests of the State. Considering the litigation history of privacy invasion suits against the government in which the majority of decisions are in favor of the state, ETC users will not have much protection. In most instances, the government will obtain available ETC system account information, if necessary.
Under the FOIA, Exemption Six, personal information is subject to a balancing test conducted by the government agency (e.g. ETC system agency, state DOT). Additionally, it is unclear if ETC account information is protected since the exemption does not specifically mention the protection of ETC account information. The exemption protects personnel, medical, and similar information, and it is difficult to interpret its applicability to ETC account information.
The ECPA provides civil and criminal punishment for the unauthorized use of electronic communications. Upon initial inspection, it appears that the ECPA could protect against an external security breach between a transponder and a transceiver, however, the law does not apply to vehicle- tracking technologies, such as automatic vehicle identification. Thus, it appears that this law is ineffective for protecting ETC communications and information.
ITS America has developed privacy principles to assist ITS and ETC agencies. These principles are not enforceable, yet they may assist ETC system agencies’ development of their own policies. It seems, however, that ETC agencies have not sought the support of ITS America. Nor have ETC agencies developed formal and public privacy policies, as ITS America has recommended. ETC agencies do address privacy issues, however, the absence of formal guidelines to define relationships with law enforcement agencies and to address FOIA exemptions weakens ETC system users’ privacy protection.
Several ETC agencies reported to exchange information with local law enforcement agencies under special circumstances, yet accounts were not monitored for motorist surveillance or traffic law enforcement necessarily. The relationship between the ETC agency and law enforcement agency is potentially problematic in that a distinct boundary may not exist. This boundary should be established to define the type of account information that the ETC agency, as a representative of its
D-16 users, is willing to share. A zealous law enforcement agency may attempt to obtain account records and conduct surveillance to conveniently enforce traffic laws or meet quotas. This behavior would most likely be unacceptable to most ETC system users, and an agency should not assume it to be acceptable without evidence.
Another problematic issue is an ETC agency’s policy about disclosure to non-law enforcement entities. While only one agency reported to disclose name and address information to outside parties, only two agencies reported to have a formal privacy policy for its employees. Agencies may not have distinct protocol for managing external requests for account information and to employ the balancing test required by the FOIA exemption.
Six out of seven surveyed ETC agencies utilize read-only or read/write transponder technologies which do not contain sufficient on-board memory to transact tolls and maintain account balances within the transponder. These transponder technologies limit the degree of anonymity within the ETC system since transaction and account information must be maintained in a centralized information bank.
Within the transportation and electronic toll collection industry, it appears that a unified organization has not emerged to effectively address privacy issues and effect changes in policies and laws. ITS America appears unrecognized by ETC agencies to develop formal agency privacy policies, identify problematic issues such as ETC agency-law enforcement agency relationships and management of the FOIA exemption and information disclosure, and assess the effectiveness of AVI and ETC technologies.
D-17 APPLICATION OF RESEARCH FINDINGS
Based on the research findings, several applications are recommended for both ETC agencies and ITS America. The applications for ETC agencies outline procedures to develop ETC systems that more effectively protect personal privacy. The recommended applications for ITS America are intended to encourage leadership from a unified organization that can more effectively coordinate ETC policy and technology research and suggest improvements to privacy protection.
ETC Agency Policy
ETC agencies may protect users’ privacies through the implementation of a secure, distinct, and understandable privacy policy. This policy should address information access and disclosure issues, and a complete or condensed version of the policy should be publicly available.
Information Access
Technology and billing and auditing procedures may determine the type of and duration that information must be maintained, however, it is possible to regulate account accessibility. Account controls can both minimize and impose barriers to accessibility. Information should be accessed by only employees that manage accounts, and these employees’ criminal records should be screened for fraudulent activities. All account access should occur within one central location; the system should not be networked with external computers or accessible from toll plaza computers. In addition, account information should be archived in a less accessible format after a designated period of time. Information should be archived when it is no longer necessary for routine management, yet still required for less frequent operations.
Information Disclosure
A secure policy should be established which addresses protocol for information disclosure requests and actual disclosure. It is recommended that all communication media be operated within one agency office. Requests for account information may arrive by postal service, telephone, electronic mail, fax, and personal delivery. By routing all requests through one office, they may be addressed consistently and in both the agency’s and the users’ best interests. Employees should also be instructed to direct all requests to this office.
The agency should establish rules for disclosing information to outside parties. Requests may come from the private sector (e.g. marketing analysts), individuals, law enforcement, or a court- ordered subpoena. The agency should decide which requests that they are willing to honor. In the case of a subpoenaed document, they may have no choice other than compliance. The agency may also feel an obligation to cooperate with law enforcement, and this relationship must be defined.
ETC account information may serve as an effective tool for law enforcement apprehension of tollway violators, car thieves, or felony criminal suspects. It may also provide a convenient method of identify traffic law violators and conducting surveillance on ETC system users. It is unlikely that the public will support using ETC account information to enforce traffic laws and track
D-18 motorists. An ETC agency should establish an agreement with local law enforcement agencies that identifies the type of information that they are willing to disclose. This agreement will establish a boundary between acceptable and unacceptable use of ETC account information.
The ETC agency should establish a balancing test to justify information disclosure to outside parties other than law enforcement or judicial entities. For the most part, information should not be given to outside parties, with a few exceptions. Transaction history information may be reduced to provide an indication of travel origin and destination profiles, and this may be valuable for transportation planning or marketing analyses. Anonymous information, such as this, could be disclosed to market analysts or transportation planners at the agency’s discretion. However, no individually identifiable information should be disclosed. Also, it may be necessary to cooperate with other ETC agencies in the community by exchanging account information. Individually identifiable and financial information should not be exchanged without consent of the individual.
All information disclosures should be managed by authorized personnel and through a common office, similar to information requests. Only this authorized personnel should be able to download or remove account information from the system.
Policy Documentation
The ETC agency should develop a formal document outlining their policies concerning information access and disclosure, among other policies. This document may serve to educate employees about information management, security, and privacy protection procedures, and it may help the agency anticipate incidents and outline methods to address privacy issues. A version of the agency’s formal privacy policy should be available to the public when they apply to use the ETC system or upon their request. This public document will inform persons about the agency’s methods of maintaining information and protecting personal privacy. It may serve to enhance public confidence and encourage motorists to use the ETC system.
ITS America Leadership
ITS America has the ability to represent ETC agencies’ interests, encourage development of secure privacy policies and ETC technologies, and introduce amendments to US privacy laws. The leadership of ITS America may effect changes within the ETC community which more effectively protect personal privacy.
ITS America has developed privacy principles to ITS agencies, including ETC agencies, develop their own privacy policies. A campaign to introduce these privacy principles to ETC agencies is the initial step in fostering relationships and earning support and recognition of these agencies. ETC agencies could benefit from ITS America as a medium for discussing innovative ideas and evaluating privacy policy. Once policy guidelines are introduced, ITS America may offer support as ETC agencies develop privacy policy. As standardized privacy policies develop, ETC agencies will have confidence that they are protecting user privacy, and the ETC industry may react to issues as a community.
D-19 As a respected and recognized organization, ITS America may initiate efforts to evaluate current US privacy laws and recommend modifications which will more effectively address electronic toll collection. Privacy laws have the potential to offer significant privacy protection, but an organization is necessary to represent the ideals of ETC agencies and privacy advocates.
Current ETC and AVI technologies and billing and auditing practices influence the type, amount, and duration of information needed for ETC system operation. ITS America may encourage thought and analysis of technologies which may minimize the amount of information required within a centralized information base. The organization may also review ETC billing and auditing procedures to determine if alternate methods may allow minimal information maintenance.
D-20 ACKNOWLEDGMENTS
This report was produced for the graduate level civil engineering course, Advanced Surface Transportation Systems, at the Texas A&M University. I would like to thank Dr. Conrad Dudek for his encouragement and his effort to organize this course. I am especially grateful for the support and guidance of Colin A. Rayman and Ginger Gherardi. I would also like to thank Leslie Jacobson, Walt Dunn, Jack Kay, and Thomas Werner for their participation. I greatly appreciate their interest in the most recent generation of transportation professionals. In addition, I would like to acknowledge the assistance of:
Michele MacDowell, California Private Transportation Company Steve Pustelnyk, Orlando-Orange Co. Expressway Authority Neal MacDonald, Illinois State Toll Highway Authority Norman Richardson, Greater New Orleans Expressway Commission Michael Zimmerman, New York State Thruway Authority Mary Audd, Oklahoma Turnpike Authority Kay Aune, Harris County Toll Road Authority
D-21 REFERENCES
1. Zhang, Wen et. al. A Primer on Electronic Toll Collection Technologies. Preprint. Transportation Research Board, 74th Annual Meeting. Washington, D.C. January 1995.
2. An ETTM Primer for Transportation and Toll Officials. ATMS Committee and ETTM Task Force, Intelligent Transportation Society of America. Washington, D.C. March 1995.
3. Pietrzyk, Michael C. and Mierzejewski, Edward A. “Electronic Toll Collection Systems: The Future Is Now.” TR News. Number 175, November - December 1994.
4. Mineta, Norman Y. “Transportation, Technology, and Privacy.” Santa Clara Computer and High-Technology Law Journal. Volume 11, Number 1, pp. 3-9. University of Santa Clara, School of Law. 1995.
5. Parent, William A. “Privacy: A Brief Survey of the Conceptual Landscape.” Santa Clara Computer and High-Technology Law Journal. Volume 11, Number 1, pp. 21-26. University of Santa Clara, School of Law. 1995.
6. Dingle, Julie. “IVHS and the Law of Privacy.” Proceedings, Pacific Rim TransTech Conference. Volume 1. American Society of Civil Engineers. New York. 15 December 1993.
7. Alpert, Sheri A. Privacy and Intelligent Highways: Finding the Right of Way. Santa Clara Computer and High-Technology Law Journal. Volume 11, Number 1, pp. 97-118. University of Santa Clara, School of Law. 1995.
8. Wright, Tom. “Eyes on the Road: Privacy and ITS.” Traffic Technology International. Autumn 1995.
9. Agre, Phil. “Technology and Privacy in Intelligent Transportation Systems.” Conference on Computers, Freedom, and Privacy. [gopher://www-techlaw.stanford.edu]. March 1995.
10. Agre, Philip E. “Abuse of Highway Toll Information.” In PRIVACY Forum Digest. Volume 5, Issue 11. [http://gopher.vortex.com/privacy/priv.05.11.Z]. 1 June 1996.
11. Agre, Phil. “Looking Down the Road: Transport Informatics and the New Landscape of Privacy Issues.” In CPSR Newsletter. Volume 13, Number 3, pp. 15-20. [http://weber.ucsd.edu/~pagre/its-cpsr.html]. 1995.
12. Rheingold, Howard. “We Need Privacy Protection on Intelligent Highways.” [http//www.well.com/user/hlr/tomorrow/highway.html]. 10 November 1995.
13. Freedom of Information Act Guide & Privacy Act Overview. Office of Information and Privacy, US Department of Justice, Washington, D.C. September 1995.
D-22 14. A Citizen’s Guide on Using the Freedom of Information Act and the Privacy Act of 1974 to Request Government Records. United States Government Printing Office. Washington, D.C. 1995.
15. Draft Final - Intelligent Transportation Systems Fair Information and Privacy Principles. Intelligent Transportation Society of America. [http//www.itsa.org/itsa/trandocs/draft.final] 13 December 1994.
D-23 APPENDIX
ELECTRONIC TOLL COLLECTION AGENCY SURVEY
1. What type of user information is collected for billing purposes?
2. What other information is maintained (e.g. travel history)?
3. How long are a user’s records maintained?
4. What security measures are in place to ensure information security?
5. Who has access to user account information?
6. Who is responsible for maintaining the information?
7. Has an outside party ever requested user information?
8. [If “yes” to question 7, then] who requested the information and for what reason?
9. Has user information ever been subpoenaed?
10. [If “yes” to question 9, then] why was it subpoenaed?
11. Do law enforcement officials use the user information for law enforcement purposes, or have they requested it for law enforcement purposes?
12. [If “yes” to question 11, then] for what purpose do they use the information or did they request the information?
13. Are users able to request a copy of their account information?
14. Are users allowed to appeal the status of their account information?
15. Does the agency have a formal, written policy that addresses privacy issues?
16. Did the agency consult with ITS America’s privacy principles when developing its policy?
D-24 Douglas J. Holdener received his B.S. degree in Civil Engineering in May, 1995 from Washington University in St. Louis, MO. He is currently pursuing an M.S. degree in Civil Engineering at Texas A&M University with an emphasis on transportation science. During the summer of 1994, Mr. Holdener participated in the Undergraduate Transportation Engineering Fellows Program at Texas A&M University. Douglas has conducted research on Determining Probe Vehicle Sample Sizes For Real- Time Information, and his work has been presented at the 75th Annual Conference of the Transportation Research Board and published in theProceedings of the 3rd Annual Meeting of the Intelligent Transportation Society of America. Douglas has served as president of the Texas A&M Institute of Transportation Engineers Student Chapter, and he is a member of ITS America and the American Society of Civil Engineers. Douglas was selected by the Eno Center for Transportation Leadership Development to become an Eno Fellow and attend the 1996 Leadership Development Conference. Currently, Douglas is employed by the Texas Transportation Institute as a Graduate Research Assistant and is investigating the effect of signal density and progression quality on urban arterial travel times. His area of interest are: transportation law, signalized intersection operations, Intelligent Transportation Issues, and intermodal connectivity.
D-25 THE USE OF ELECTRONIC TOLL AND TRAFFIC MANAGEMENT SYSTEMS FOR FREEWAY INCIDENT DETECTION
by
A. Bowman Kelly
Professional Mentor Thomas C. Werner, P.E. New York State Department of Transportation
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas
August 1996 SUMMARY
Increasing levels of congestion on urban freeways has emphasized the need for an effective means of detecting and responding to traffic incidents. Traditional methods of incident detection have depended on inductive loop detectors embedded in the pavement. There are a number of problems associated with loop-based incident detection. Therefore, traffic engineers have begun to study Automatic Vehicle Identification systems as a means of incident detection.
Problems associated with loop-based incident detection include the cost of installing and maintaining a network of inductive loops, the efficiency and time constraints of loop detector algorithms, and the limited focus of loop detector data.
Concurrent with the growth in urban congestion, Electronic Toll Collection systems have emerged in recent years as a method of reducing delay and congestion at toll plazas. These systems permit the motorist to pay toll fees electronically and can greatly reduce the infrastructure and maintenance costs of toll plazas.
It is felt that the technology used for Electronic Toll Collection could be used for other purposes, specifically for traffic incident detection. Incident detection through Electronic Toll Collection methods is known as Electronic Toll and Traffic Management or ETTM. There are several advantages to this approach. ETTM can provide traffic managers with real-time access to highway congestion data, as well as travel time information for various links in the roadway network.
The cost of ETTM-based incident detection compares favorable with loop-based incident detection and has the advantage of lower indirect costs to the motorists and tangible benefits to the public through more efficient use of tollway facilities.
E-ii TABLE OF CONTENTS
INTRODUCTION ...... E-1 Problem Statement ...... E-1 Research Objectives ...... E-2 Scope ...... E-3
INDUCTIVE LOOP DETECTORS ...... E-4 Incident Detection Algorithms ...... E-4 Classification of Incident Detection Algorithms ...... E-5 Comparative Algorithms ...... E-6 Statistical Algorithms ...... E-6 Time Series Algorithms ...... E-7 Smoothing/Filtering Algorithms ...... E-8 Traffic Modeling Algorithms ...... E-9 Detection Algorithm Utilization ...... E-10 Summary ...... E-12
ELECTRONIC TOLL COLLECTION ...... E-13 Manual Toll Collection ...... E-13 Electronic Toll Systems ...... E-14 ETTM Incident Detection ...... E-20 ETTM Detection Algorithm ...... E-21
PUBLIC AND PRIVATE COSTS FOR INCIDENT DETECTION ...... E-23 Loop Detection Costs ...... E-23 ETTM Detection Costs ...... E-24
CONCLUSIONS ...... E-25
RECOMMENDATIONS ...... E-26
ACKNOWLEDGMENTS ...... E-27
REFERENCES ...... E-28
E-iii INTRODUCTION
Real-time traffic incident detection is an essential element of congestion management. Incident information can be used by the public to plan the most efficient route and avoid congested areas. Traditionally, incident detection has been accomplished by inductive loop detectors imbedded in the pavement of freeways in urban areas. However, loop detection produces a trade off in accuracy between the percent of actual incidents detected and the number of false alarms. In addition, other problems have been associated with loop detection algorithms and the response time of these algorithms. As congestion levels continue to rise in most American cities, traffic agencies have begun to study Intelligent Transportation Systems (ITS) as a means of reliable incident detection at a reasonable cost. One approach of ITS is to use probe vehicles in the traffic stream to measure the travel time between points along a roadway. This approach is known as Automatic Vehicle Identification or AVI. The AVI system consists of an electronic identification tag (transponder) carried on board the probe vehicle, a roadside communications unit (reader) used to locate and track vehicles, and a central control center where probe vehicle locations throughout the network are monitored.
Another type of AVI system is Electronic Toll Collection (ETC). In this system, an ETC- equipped vehicle carries information that permits the vehicle operator to pay toll fees electronically. As the motorist moves through various toll stations, the ETC system records his or her transactions automatically. With its ability to monitor individual vehicle travel times, an ETC system could be used for other ITS applications, that is, vehicles equipped with ETC transponders could be used for incident detection. This combination of an AVI-based electronic toll collection system and secondary ITS applications will be referred to as Electronic Toll and Traffic Management or ETTM. These systems have the potential to detect traffic incidents more accurately than an inductive loop- based incident detection system.
For the purposes of this study, a traffic incident will be defined as an unpredictable and non- recurring event which causes a temporary reduction in the capacity of a freeway. Traffic incidents have the following characteristics: a queue forms upstream of the event, a shockwave propagates upstream of the event, and the running speed of vehicles upstream of the event drop significantly below the safe operating speed of the roadway. In this study, incidents are limited to those that result in a blocked lane due to an accident or a stalled vehicle. Congestion caused by snow, icy roads, or a disabled vehicle on the shoulder will not be part of the study although these events have the same effect on congestion as an incident.
Problem Statement
Freeway surveillance and control centers currently operate in several metropolitan areas of the country such as Houston, San Antonio, and Seattle. The purpose of these centers is to improve traffic operations (maintain reasonable running speeds and travel time) in the freeway corridors. These centers detect the presence of congestion and incidents that result in congestion; dispatch personnel to clear incidents from the freeway; and inform motorists about the location of incidents and/or congestion. They also advise the public about expected travel time delays and alternative routes around the congestion.
E-1 Coinciding with the establishment of freeway control centers, electronic toll collection (ETC) systems are currently operating in urban areas such as Dallas, Orlando and New York. Electronic toll collection offers toll authorities a means of collecting tolls with significant reductions in infrastructure, operating and maintenance costs.
Traditional methods of incident detection have relied on inductive loop detectors to provide speed and volume data. Since an ETC system monitors vehicle locations and travel times, it may provide a more reliable and cost-effective means of incident detection (fewer false alarms per given percent of incidents detected). Establishing a spacing pattern for ETC roadside readers is necessary to compare ETC-based incident detection with loop-based incident detection. The percent of ETC equipped vehicles in the traffic stream (penetration) required for a level of detection accuracy which meets or exceeds the accuracy of loop-based detection systems is another factor in this comparison.
Research Objectives
This study was designed to provide minimum spacing and penetration requirements for an effective ETC-based incident detection system. The comparison included the cost per mile of roadway for an ETC incident detection system versus a loop-based detector system. Specific research objectives were as follows:
1. Explore the effectiveness of loop detectors and loop detector algorithms for incident detection. The measures of effectiveness are the loop detector spacing, the percent of total incidents not detected, the percent of total reported incidents that are false alarms, and the time required to detect an incident.
2. Estimate the spacing for ETC roadside communications units and the required number of probe vehicles to provide a similar level of incident detection as the loop detector method. The level of incident detection is based on the measures of effectiveness described above. For example, if loop detectors yield an 82% incident detection rate, 2% false alarms, and a one minute lag time, then the estimated ETC spacing would provide same detection rates.
3. Compare the cost of ETC-based incident detection with the cost of loop-based incident detection. Factors the study will consider include these items: the cost of installing loops, road user costs of installing and maintaining loop-based incident detection (delay time and congestion resulting from a lane closure due to loop installation), cost of installing an ETC roadside unit, maintenance cost of an ETC roadside unit, percent of ETC equipped vehicles in the traffic stream required for a specified level of incident detection (penetration), installation and maintenance cost of the onboard ETC component (transponder).
E-2 4. Develop recommendations for cities seeking to establish (or expand) an incident detection system based on the New York Metropolitan area’s TRANSCOM ETTM incident detection system. The recommendations will consider penetration, the cost per mile of roadway (a function of spacing), and the level of incident detection for an inductive loop system.
Scope
The study examined an ETTM system in the New York Metropolitan area. It does not describe all possible ETTM technologies. Its focus was on how the existing system operates, and a discussion of vehicle identification and location methods. The basis of this research was a literature review of information related to electronic toll collection and inductive loop incident detection methods. Next, the costs and technical problems of both ETC-based and inductive loop- based incident detection were investigated and identified. From information collected through the literature search and interviews, an ETC-based incident detection system was compared with a loop- based system. If ETC provided a cost-effective alternative to loop-based incident detection, the research was to be applied to a case study of the Houston, Texas incident detection system. If ETC did not provide a cost-effective alternative to loop detection, the study was to describe the shortcomings of the ETC incident detection system.
E-3 INDUCTIVE LOOP DETECTORS
Inductive loop detectors operate as a tuned LRC circuit*. A vehicle entering the detection zone changes the resonant frequency of the circuit, and the change is registered by the detector logic. This time segment, when the detector is “on”, is called occupancy time. Occupancy time is the time required for the vehicle to travel a distance equal to its length plus the length of the detection zone (1). The percent occupancy time is the proportion of time when the detector is “on” or occupied compared to the total time of the sample period. Percent occupancy time can be used to calculate traffic density as follows:
where k = density (vehicles per mile) LD = detection zone length (feet) LV = average length of a vehicle (feet) %OCC = percent occupancy time 52.8 = proportionality constant (vehicle-feet per mile)
Since loop detectors can sense the presence of vehicles, a series of loop detectors along a freeway can indicate areas that have a high percent occupancy time. These areas are characterized by a high density, low operating speed, and low flow rates. May, (1), suggests that when percent occupancy is between 17 and 28, traffic conditions correspond to Level-of-Service E. Further, when percent occupancy exceeds 42, the congested flow conditions are similar to those caused by an incident. Note that these figures assume that (LD +LV) = 22 feet. While percent occupancy does not by itself indicate the occurrence of an incident, it can be used as an input variable for incident detection algorithms.
Incident Detection Algorithms
There are many types of incident detection algorithms, each with their advantages and disadvantages. The measures of effectiveness (MOEs) for these algorithms are: the detection rate (percent of total nonrecurring incidents reported), the false alarm rate (percent of total reported incidents that are spurious), and the detection time. Generally, a tradeoff is made in one or more of the MOEs to emphasize another. For example, one algorithm may provide a very good detection rate but have a slow detection time. Another might have a low false alarm rate and a quick detection time but fail to register a large proportion of actual incidents. The structure of a particular algorithm affects its performance through these measures of effectiveness (2). Some algorithms use statistical techniques to detect changes in traffic conditions over time. Others compare direct measurements
* An electric circuit with inductive, resistive, and capacitative elements.
E-4 of traffic to preestablished threshold values. Another type uses complex theoretical models to predict traffic conditions given current conditions and historical trends. To illustrate the tradeoffs between different measure of effectiveness, refer to Figure 1 below:
Figure 1. Relationship Between Detection Rate, False Alarm Rate, and Detection Time (2).
An effective incident detection algorithm strikes a balance between an acceptable incident detection rate and acceptable false alarm rate within a reasonable detection period.
Classification of Incident Detection Algorithms
Balke categorized incident detection algorithms into five groups based on the underlying traffic flow principle or mathematical principle employed by the algorithm, (2). These groups are listed below:
• Comparative Algorithms; • Statistical Algorithms; • Time-Series Algorithms; • Filtering Algorithms; and • Traffic Modeling Algorithms.
E-5 While each group contains at least two algorithms, only a limited number are currently used by traffic operators to detect freeway incidents.
Comparative Algorithms
Comparative algorithms assume that an incident will increase loop detector percent occupancy upstream of the event and decrease the percent occupancy downstream of the event. This algorithm compares the measured value of a traffic parameter, such as occupancy, volume, or speed, to an established threshold value. When the measured value exceeds the threshold value, the algorithm signals an alarm. Once an incident is detected, the comparative algorithm may sample and test the incoming data to distinguish between incident congestion and bottleneck congestion. Further tests determine if the incident has been cleared or check that the incident pattern is not caused by random fluctuations in the traffic stream. The most widely known comparative algorithms in the United States are the California Algorithm and the Modified California Algorithm.
The basic California Algorithm compares occupancy levels between two adjacent detectors (assumed to be one-half mile apart) for the difference in occupancy between the upstream and downstream detector. It also checks the differences in occupancy between the upstream and downstream stations relative to the occupancy level at the upstream station, and the difference in occupancy between the downstream station and its level over the previous two minutes. An incident is declared when all three of these parameters exceed preestablished thresholds, (2). Additional tests cancel the incident alarm after a specified period when one parameter falls below its threshold level.
Modified California Algorithms, based on the California Algorithm, use persistence checks and compression wave tests to reduce the false alarm rate. Persistence checks ignore short-lived traffic pattern aberrations (found in most traffic streams) and sound an incident alarm only if the condition persists for a specified period. While persistence checks reduced the rate of false alarms, they increase the detection time. A compression wave is a sudden increase in density that moves upstream of the prevailing traffic flow. In 1976 Payne et al, (3), tested ten modified versions of the California Algorithm. In modification #7, the third parameter of the basic algorithm was replaced with a measurement of the current downstream occupancy level in an effort to more readily identify compression wave disturbances. A persistence check, incorporated into modification #7, requires that incident conditions last for at least two iterations of the algorithm before sounding an alarm. Modification #8 suppresses the incident alarm for five minutes after a compression wave has been detected.
Statistical Algorithms
Statistical algorithms compare observed detector data with an estimated (predicted) value. Standard statistical tests then determine if the difference is statistically different from zero. Statistical algorithms are exemplified by the Standard Normal Deviate (SND) algorithm.
Dudek, Messer and Nuckles developed the SND algorithm in the mid-1970s, (4). Assuming that sudden changes in a measured traffic variable are indicative of an incident, the algorithm monitors trends in the variable and sounds an alarm if it deviates more rapidly than expected. For a given traffic variable mean, a Standard Normal Deviate is the number of deviations the observed
E-6 value lies from the mean value. It reflects the degree that the observed measurement, say the one minute average of loop occupancy, has changed during a given interval compared to the previous three minute average of loop occupancy. A measured SND value that exceeds the predefined threshold SND value indicates a significant change in the operating conditions of the freeway.
Two strategies have been developed for the SND algorithm. The first requires that only the present minute of SND value exceed the threshold value, while the second requires that two successive SND values exceed the threshold value. In effect, the second strategy has a built-in persistency check. For either strategy, one of two methods can be used to compute the mean and standard deviation of the control variable. The first method uses data from the previous three minutes of observation time and the second uses data from the previous five minutes.
Time Series Algorithms
These algorithms assume that traffic flow follows a predictable pattern over time. The algorithm predicts short-term future traffic conditions based on historical data for the detection zone. When the difference between the observed and predicted values falls outside an acceptable range, the algorithm signals an incident.
Figure 2. Approach Used In Time Series Algorithms (2).
E-7 Figure 2 illustrates the technique used by Time Series Algorithms to detect incidents. Loop occupancy (solid line) is monitored over time while the algorithm the algorithm uses times series statistical techniques to predict future values of the variable. Confidence intervals (dashed lines) are superimposed on the graph. An incident alarm is sounded when the observed data crosses outside the confidence interval. Common Time Series algorithms include the ARIMA algorithm, developed by Ahmed and Cook, (5), and the High Occupancy algorithm, developed in England.
Smoothing/Filtering Algorithms
Due to the dynamic nature of traffic flow, loop detector occupancy viewed over time vacillates with a number of peaks and valleys. It is these vacillations that are responsible for causing false alarms with most incident detection algorithms. Many algorithms have persistence checks to reduce the rate of false alarms, but the persistence checks can significantly increase detection time. Filtering algorithms remove the short-term fluctuations that cause false alarms by smoothing or filtering the raw data. These algorithms utilize weighted averages of observed traffic data to reduce the effects of outliers and random fluctuations on predicted traffic values. Filtering algorithms are particularly useful when the detector data is contaminated by electromagnetic noise. The Low-Pass Filter algorithm and the Exponential Smoothing algorithm are examples of filtering algorithms. A graph representing traffic data before and after it has been “filtered” is shown in figure 3 below:
Figure 3. Approach Used In Smoothing/Filtering Algorithms (2).
E-8 Traffic Modeling Algorithms
Traffic Modeling algorithms employ complex traffic flow theories to predict the behavior of traffic under incident conditions. The algorithms then compare the theorized values with observed values of the chosen variable. The McMaster algorithm is a single-station traffic modeling algorithm. It uses the speed-flow-occupancy relationship to judge when traffic conditions change at a detection station. This algorithm assumes that when the traffic stream moves from the uncongested state to a congested state, flow and occupancy change smoothly while speed changes rapidly. Historical data from a detector determines the flow-occupancy relationship for that station. Persuad, Hall and Hall, (6), observed that the relationship between volume and occupancy appeared curvilinear. This curve can be used to distinguish when traffic moves from uncongested to congested flow.
In Figure 4 below, four states are separated by the lower bound of uncongested data (LUD), critical occupancy (Ocrit), and the critical volume (Vcrit). State 1 is the uncongested traffic state with high flow rates and low occupancies. State 2 represents congested flow and State 3 depicts heavily congested traffic flow. State 4 reflects traffic operations as they appear downstream of a permanent bottleneck on a freeway operating at capacity. The algorithm uses two tests to detect incidents. In the first, raw detector data is compared to the graph developed for that station. If traffic conditions fall below the LUD curve (States 2 or 3) for longer than three consecutive 30-second intervals, the station is deemed to be congested. When the algorithm detects congestion at a station, it evaluates the traffic state at a downstream detector. If the downstream station is relatively clear (States 1 or 2) then it is likely that an incident has occurred between the stations.
Figure 4. Flow-Occupancy Graph for McMaster Algorithm (2).
E-9 The McMaster algorithm uses volume and occupancy data from a single detector station to classify traffic conditions on the freeway. Raw measurements of volume and occupancy levels are compared to the graph for each station. To calibrate the algorithm, the LUD curve, Ocrit, and Vcrit must all be defined. The LUD curve is calibrated with three days of incident-free data and a quadratic function is used to fit the LUD to the flow-occupancy boundary. Critical occupancy is defined as the occupancy where the highest observed volume occurred. To establish critical volume, recurrent congestion must occur at a detector station.
Detection Algorithm Utilization
Balke’s report, (2), noted that seven freeway management centers in the United States and Canada either use, or have used, incident detection algorithms. The Los Angles, Northern Virginia, and Chicago centers utilize a modified version of the California (Comparative ) Algorithm in conjunction with either television surveillance, motorist assistance patrols, police patrols, or other methods to detect incidents on their freeway systems.
In Los Angles, a single loop detector embedded in each lane continuously collects traffic volume and occupancy data, then averages the data in 30 second intervals. The average occupancy at each detector station is smoothed with the previous two minutes of data. When the algorithm detects an incident, it notes the time and traffic zone location of the incident, then waits for six cycles (three minutes) as a persistency check. If incident conditions still exist after six cycles, the system alerts the operator. Although the same algorithm is used throughout the surveillance area, incident detection is performed on a zone-by-zone basis with threshold values computed for each zone.
The Northern Virginia traffic management center uses a different approach. A modified version of the California algorithm detects zones of congestion. A traffic system operator then decides, through a visual inspection of the area with closed-circuit television cameras, whether the congestion is caused by recurring bottleneck conditions or by an incident. The algorithm then calculates the capacity of the congested area and uses this value in a ramp metering control system.
In Chicago, the Illinois Department of Transportation Traffic System Center monitors roughly 2000 loop detectors on eight separate freeways. Detector stations are spaced every ½ mile along 130 centerline miles of highway. Each detector station consists of a single inductive loop and these loops are placed in only the center lane of the freeway. The loop detectors are polled by a central computer that develops one minute averages for volume and occupancy based on five minutes of observed traffic data at two adjacent detector stations. The system currently uses a comparative algorithm although a Bayesian (statistical) algorithm and the California algorithm were used experimentally in the past. A comparative algorithm declares an incident when the occupancy levels at both detector stations exceed the following conditions:
E-10 Lane Occupancy Time Upstream Downstream T $ 30% # 10% T-1 $ 30% # 10% T-2 $ 28% # 12% T-3 $ 26% # 14% T-4 $ 24% # 16%
In addition to the loop detector system, the Illinois D.O.T. relies on a motorist assistance patrol, aerial surveillance by traffic news services, reports from cellular telephone users, and police patrols to provide it with traffic and congestion information.
In 1992, the Ontario Ministry of Transportation began using the McMaster algorithm to monitor freeways in the Toronto area. The freeway management system provides continuous surveillance on over 27 km (16 miles) on Highway 401. It includes 220 loop detectors, 37 video surveillance cameras, and 13 LED changeable message signs. Inductive loops collect volume, occupancy, and speed data across all lanes at each detector station. The aggregated data is transmitted to a central computer every 20 seconds where the data is checked at a rate of three times per minute. Originally, the Ministry used both a comparative algorithm and a smoothing/filtering algorithm for automatic incident detection. Recently, the Ministry has switched to the McMaster algorithm. They feel it generally provides a false alarm rate superior to that of the comparative and filtering algorithms, (2).
Three freeway management centers studied in Balke’s report (2) have used comparative incident detection algorithms in the past, but have discontinued using them. The Seattle, Minneapolis, and Long Island, New York systems previously used modified versions of the California algorithm in conjunction with their loop detector networks. While these centers still use inductive loops to detect congestion, they were dissatisfied with the high number of false alarms produced by the California algorithm. Instead, traffic managers at these centers rely on an array of closed-circuit television cameras, police and maintenance patrols, and the training and experience of their operators for incident detection. The Minneapolis center tends to rely on an extensive network of video cameras for incident detection. Seattle depends more on service patrols and reports from CB radio traffic. The Seattle and Minneapolis agencies feel that “report-based” incident detection provides an adequate response time without the high number of false alarms. In both cases, improper calibration appears to be the most likely reason why the algorithm produced a high number of false alarms. Calibration is a process of establishing threshold values that distinguish between incident and nonincident conditions. Traffic data under incident conditions is needed to set the thresholds, while traffic data under nonincident conditions is required to identify areas with unusual geometry and to assess the false alarm rate. Since geometric design elements such as lane drops, weaving sections, or steep grades affect traffic flow, the algorithm must be calibrated on a zone-by- zone basis to be effective. Ideally, every detector station in the network would be individually calibrated based on its unique traffic and geometric alignment characteristics.
E-11 Summary
Numerous algorithms have been developed to detect lane-blocking incidents for freeway surveillance systems. The algorithms use a variety of methods for detecting incidents. Some use a simple comparisons of measured traffic data to preestablished thresholds. Others employ theoretical traffic flow models to predict future traffic conditions based on current observations. The performance rating of a particular algorithm is defined in terms of detection rate, false alarm rate, and detections time. Table 1 lists the optimal performance rates for these parameters.
Table 1. Reported Best Performance of Existing Incident Detection Algorithms (2).
Algorithm Class Detection False Average Detection Rate Alarm Detection Variable(s) Rate Time Basic California Comparative 82% 1.73% 0.85 mins Occupancy Modified Comparative 67% 0.134% 2.91 mins Occupancy California #7 Modified Comparative 68% 0.177% 3.04 mins Occupancy California #8 Standard Normal Statistical 92% 1.3% 1.1 mins Occupancy, Deviate Volume Time Series Time Series 100% 0% 0.4 mins Occupancy, ARIMA Volume Exponential Smoothing/ 92% 1.87% 0.7 mins Occupancy Smoothing Filtering Low-Pass Filter Smoothing/ 80% 0.3% 4.0 mins Occupancy Filtering McMaster Traffic Model 68% 0.0018% 2.2 mins Occupancy, Volume
Freeway management centers in Los Angles, Northern Virginia, and Chicago centers use a modified version of the California Algorithm in conjunction with either television surveillance, motorist assistance patrols, police patrols, or other methods to detect incidents on their freeway systems. Other locales have discontinued using incident detection algorithms citing the high false alarm rate.
E-12 ELECTRONIC TOLL COLLECTION
Increasing levels of traffic congestion in American urban areas has emphasized the need for an effective congestion management system. In recent years, some traffic agencies have begun to study Intelligent Transportation Systems (ITS) as a means of identifying congested facilities and initiating measures to reduce the congestion in a timely manner at a reasonable cost. Three types of Intelligent Transportation Systems, currently used to track and identify vehicles for scheduling or toll purposes, may provide secondary benefits for congestion management: Automatic Vehicle Identification (AVI), Automatic Vehicle Location (AVL), and Electronic Toll Collection (ETC). The common goal of these systems is to identify a vehicle as it remains in motion and to locate that vehicle relative to its surroundings
There are many types of AVI technologies. Some systems use microwave or radio frequency transmitters. Optical or Infrared scanners have been proposed for other systems. GPS, the Global Positioning System, is an emerging technology that could be applied to Automatic Vehicle Identification, (7). Regardless of the particular technology, all of these systems use on-board electronics to identify vehicles, a roadside receiver/transmitter to track vehicles, and a central control center to process and coordinate the data.
The on-board components may range from a simple bar code tag to an electronic smart-card, but generally use a special type of radio frequency transmitter called a Transponder. On-board components uniquely identify a particular vehicle, and thus function as an electronic license plate. The Roadside Communications Unit (RCU) detects an approaching vehicle, identifies it, and sends information about that vehicle to the control center. In some systems, the vehicle assumes that its position is the same as the RCU. In others, the RCU transmits its coordinates to the vehicle and the on-board components calculate the vehicle’s position, (8). With GPS, the vehicle carries known, continuously updated coordinates and simply transmits its location data to the RCU. Once the vehicle identity and location have been established the RCU transmits that information to the control center.
The control center gathers vehicular data and takes the appropriate action. In a corridor management system, the control center would monitor the traffic flow, adjust ramp meters to control ingress to the roadway, or control changeable message signs. Other systems might regulate and oversee transit fleet schedules and headways. The key advantage is that the control center can do all of these tasks in Real-Time without adversely affecting the operating speed of the vehicle. This feature provides important cost and safety benefits for toll collection.
Manual Toll Collection
Toll facilities are established as a means of improving the existing highway infrastructure when public funds for such improvements are not available. A trip maker willing to pay a premium has access to a well maintained, high capacity facility. Alternatively, the trip maker may use a facility that is less well maintained and has a lower capacity but without paying a premium. Manual toll collection methods, while providing the funds to operate and repair a highway, result in a number of problems due the inefficient manner of collecting tolls. A partial list of drawbacks to manual toll
E-13 collect methods would include:
• Limited throughput of manual and automatic coin lanes; • High toll plaza infrastructure costs; • High toll plaza operating and maintenance costs; • Increased accident potential; and • Increased vehicular emissions.
Traditional toll plazas require either an attendant in a booth (manual lane) or an automatic coin machine to collect payments. In either case, the motorist must stop to pay the toll. The time required to service a vehicle in a toll plaza increases travel time along the highway. Toll booth attendants can process 350 vehicles per hour while automatic coin machines can process 500 vehicles per hour (9). The 1994 Highway Capacity Manual (10) states that the maximum service flow for a basic freeway section is approximately 1600 vehicles per hour per lane (assuming 70 mph free-flow speed and Level-of-Service C). Therefore, the toll plaza should supply four to five toll lanes for each highway lane. When only two or three toll lanes per highway lane are provided, queues form upstream of the toll plaza and the motorist experiences delay.
The necessity of requiring three toll lanes per highway lane results in high infrastructure, operating and maintenance costs. A toll authority has to acquire additional right-of-way, provide an expansive paved surface, install toll booths and/or automatic coin machines, and provide electric power for the toll plaza. In addition, the authority must pay to repair and maintain the toll plaza facility and provide for the attendant’s salaries.
The requirement that motorists stop to pay the toll has an adverse impact on roadway safety. High speed differentials exist between vehicles decelerating to enter the plaza and again as vehicles accelerate and leave the plaza. West and Dunn (11) describe how the rate of accidents increases as the speed deviation (the difference in speed) between vehicles increases. To compound the problem, motorists typically execute a number of lane changes as they enter the toll plaza hoping to find the booth with the shortest queue. These weaving maneuvers also have a negative impact on safety.
Congestion and long queues often form at toll plazas due to the limited throughput of traditional toll collection methods. These long queues, combined with “Stop & Go” traffic, waste fuel and increase vehicle emissions. Society pays a price for increased vehicle emissions through higher health care costs and decreased quality of life.
Electronic Toll Systems
Electronic toll collection, or ETC, is a special application of Automatic Vehicle Identification technology described earlier. ETC is designed to alleviate some of the problems associated with manual toll collection methods by offering the toll authority significant reductions in infrastructure and maintenance costs. Further, it can enhance the safety of the motoring public by reducing the speed deviations between vehicles passing through a toll plaza. A schematic of a generic ETC system is shown in figure 5.
E-14 Figure 5. Generic ETC System (12).
The on-board unit, or transponder, stores the information needed for toll transactions such as vehicle type, account identification, account balance, etc. The roadside unit (RCU) consists of (a) the transceiver (transmitter/receiver) which verifies that the on-board unit is functioning properly and communicates the transaction; (b) a lane controller that operates gates, signs and indicator lights (GO, STOP, etc) in a toll lane; and © a microprocessor, used to access account information and conduct the transaction. Although a two-way microwave link is shown in figure 5, note that a two- way radio frequency link may be used as well.
Transponders (tags) can be classified according to their communication capability as read- only (Type I) or as read/write (Type II). Type I transponders contain fixed data and are either programmed at the factory or by the agency issuing the tag. Type II transponders act like Type I transponders but have extra memory to carry information such as transaction location, lane number, time, date, account balance, etc. Their read/write capability permits data to be transferred from an upstream RCU to a downstream RCU as the vehicle traverses the highway. This ability has potential benefits for incident detection as discussed later.
In a typical ETC transaction, the roadside unit continuously broadcasts an interrogation signal to the toll lane. This is the transmission phase. When a moving vehicle enters the broadcast area, its (Type II) transponder receives the interrogating signal and replies to the RCU via the transceiver. A reply usually consists of the vehicle identification code, account number, account balance, and so forth. The roadside unit receives this reply signal during the reception phase. The RCU verifies that the reply is valid by checking an error detection and correction code in a process known as “handshaking”. If the “handshake” is successful, the computer deducts the toll from an account and sends this information back to the vehicle’s transponder. The transponder logs the toll payment and sends yet another signal to the RCU stating that a debit has been recorded. The transaction is
E-15 concluded when the transceiver reads the contents of the on-board unit’s memory to verify that the correct toll was paid.
Toll plaza traffic operations with and without ETC will differ significantly. ETC cannot and should not totally replace manual and automatic coin lanes. It is an option, a service, provided by the toll authority to the motorist as a means of reducing his or her travel time. It also has secondary benefits (positive externalities) to the motorist in the form of fuel savings and better air quality. At best, electronic toll systems can decrease the number of manual and automatic coin lanes in a toll plaza and reduce vehicle queues.
An ETC lane can be designed as either a dedicated lane or a mixed use lane. The optimal configuration depends on four characteristics: capacity by lane type, the relationship of speed to capacity, the percent of transponder-equipped vehicles in the traffic stream (penetration), and threshold volumes levels for toll plaza lane configurations (13). Existing and future toll plaza lanes can be designated as manual, automatic coin, mixed use, dedicated AVI, and express AVI. Manual or automatic coin lanes require the motorist to stop and pay a toll as in a traditional toll plaza. Mixed use lanes can accommodate vehicles with AVI gear but also provide for manual or automatic coin toll payments. Dedicated AVI lanes are located within the conventional toll plaza but are reserved for transponder-equipped vehicles. Express AVI lanes are physically separated from the conventional toll plaza, are reserved for AVI vehicles, and can accommodate speeds at or near the operating speed of the highway. As shown in figure 6, a dedicated AVI lane can service 1200 vehicles per hour (vph) compared to 350 vph for a manual lane and 500 vph for an automatic coin lane. Stated differently, the minimum time headway for a dedicated AVI lane is 3 seconds while the minimum headway for a manual lane is 10 seconds. The service rate for an express AVI lane is three to five times higher than an automatic coin lane or a manual lane (13).
Due to lower restrictions on the time headway, both speeds and volumes increase as preferential treatment for AVI lanes increase. Pietrzyk and Mierzejewski, (13), define the average running speed at a toll plaza as the speed maintained once a vehicle first stops or slows down to join a toll lane queue through the point of being processed at the toll plaza. The average running speed for a manual lane is 2.5 mph, compared to 15 mph for a dedicated AVI lane and (potentially) 55 to 70 mph for an express AVI lane. Note that retrofitting AVI lane into a conventional toll plaza would require additional planning, design and (for express AVI lanes) right-of-way costs. Figure 7 depicts the relationship of speed to various toll lane types
E-16 1800 1800
1600
1400 1200 1200
1000
700 800
600 500 Capacity (veh/Hr) 350 400
200
0 Manual Automatic Coin Mixed Use Dedicated AVI Express AVI
Toll Lane Type
Figure 6. Capacity of Toll Lane Types (13).
60 55 50
40
30
20 15 7 10 5 2.5
Average Running Speed (mph) 0 Manual Automatic Mixed Dedicated Express Coin Use AVI AVI Toll Lane Type
Figure 7. Speed of Toll Lane Types (13).
E-17 Penetration rates for transponder-equipped vehicles traversing a toll plaza on any given day are difficult to estimate. Therefore, full use of dedicated or express AVI lanes can only be assumed for an estimate level of AVI penetration. To address this concern, the Florida Department of Transportation Traffic Engineering Office has developed a toll plaza simulation model known as D- QUEUE. D-QUEUE was used to estimate the potential for plaza lane reduction using ETC under various penetration rates for different peak hour volumes (13). The model used a maximum queue length of 300 feet as the criteria for determining optimal plaza lane configurations. As shown in figure 8 below, ETC provides a greater potential for lane reduction at higher traffic volume levels.
10
9
8
7
6 3000 veh/Hr 4000 veh/Hr 5 5000 veh/Hr 6000 veh/Hr 4
3
2 Lanes Reduced (each direction)
1
0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% AVI Penetration (percent)
Figure 8. Lane Reduction and Penetration Requirements (13).
The D-QUEUE toll plaza simulation model was used again to determine the least number of toll lanes required to conduct transactions given that vehicle queues were constrained to 300 feet or less. By assuming as AVI penetration rate of twenty-five percent, the model compared the potential reduction in toll lane requirements for an ETC toll plaza versus a conventional toll plaza. Refer to figure 9 below. If traffic flow is 3,000 vehicle per hour, a conventional toll plaza would need 7 toll lanes in each direction. A toll plaza equipped with on manual lane and three or four mixed use lanes (in each direction) could service an equivalent volume (3,000 vehicles) assuming that twenty-five percent of those vehicles carry ETC transponders. Again referring to figure 9, at 2,000 vph the ETC and conventional lane requirements are roughly equal. At 3,000 vph, a significant difference in lane requirements is noted indicating the initial threshold for ETC toll plazas with mixed use lanes. Pietrzyk and Meirzejewski suggest that traffic flows of 5,000 vph and 7,000 vph justify initial consideration of dedicated AVI lanes and express AVI lanes, respectively (13).
E-18 Conventional + 25% AVI Conventional 35 30 25 20 15 10 5 (total both directions) Number of Toll Lanes 0 1000 2000 3000 4000 5000 6000 7000 Toll Plaza Volume (veh/Hr)
Figure 9. AVI Versus Conventional Toll Plaza Lanes (13).
Table 2 presents costs for the lane types discussed above based on toll systems in Florida, Dallas, Oklahoma, and information provided by AVI vendors (13). As shown in the table, dedicated AVI lanes and Express AVI lanes can significantly reduce both equipment and operating costs on a per lane basis.
E-19 Table 2. Equipment, Operating, and Maintenance Costs by Toll Lane Type (13).
Lane Type Lane Equipment Costs Operating & Maintenance Costs (per lane) (per lane) Manual $58,500 $141,900 Automatic Coin $58,000 $43,000 Manual/Automatic Coin $107,500 $111,000 Manual/AVI $72,700 $146,200 Automatic/AVI $69,500 $47,500 Mixed Use $121,300 $115,200 Dedicated AVI $15,400 $4,200 Express AVI $15,400 $4,200
Currently, more than 20 traffic agencies in eight countries have installed ETC systems, among them the Texas Turnpike Authority, the Harris County (Texas) Toll Road Authority, and the New York State Thruway Authority, (14). Another 23 of these agencies, both American and foreign, are in the process of testing, studying, or implementing electronic toll collection. Electronic toll collection systems have the potential to offer traffic operators expanded utility, that is, vehicles equipped with ETC transponders can be used for other ITS applications such as incident detection. This combination of an AVI-based electronic toll collection system and secondary ITS applications will be referred to as Electronic Toll and Traffic Management or ETTM. In an ETTM-based incident detection system, vehicles are identified at an upstream detector (RCU) and re-identified at a downstream detector. This sequential identification of a tagged vehicle, combined with the vehicle’s time of transit, permits a control center to compute the travel time between two detectors. Average vehicle speeds along a segment of freeway are estimated from travel time data and this vehicular speed data serves as the observation variable for incident detection.
ETTM Incident Detection
In 1991, TRANSCOM, a cooperative venture between traffic and transit agencies in the New York metropolitan area, began investigating the feasibility of using ETTM systems for traffic management and incident detection. The project, known as TRANSMIT, was divided into two phases. Phase 1 consisted of an evaluation of using ETTM technology for traffic surveillance and the development of a preliminary surveillance system design. Phase 2 involved finalizing the detection system design and constructing the initial stage of the system along sections of the New York State Thruway and the Garden State Parkway. Analyses were conducted to determine the RCU spacing and toll tag penetration necessary to detect an incident within five minutes, with a maximum false alarm rate of two percent. The results indicated that these measures of effectiveness could be realized with an RCU spacing of 1.5 miles. The penetration levels vary depending on the freeway
E-20 lane configuration with 0.9 percent required for two-lane facilities and 2.1 percent required for three- to-four-lane facilities, (14).
ETTM Detection Algorithm
The incident detection algorithm for TRANSMIT was developed by PB Farradyne Inc. Farradyne’s algorithm uses the normal speed distribution for each RCU location and time period to calculate the expected vehicle arrival time at the downstream station. The probability of the vehicle’s arrive at the next station is continuously calculated, and the probability of an incident is then determined. When tagged vehicles detected at an upstream station are not detected at the downstream station within the expected arrival time, the probability of an incident is set to just above zero. As the vehicle arrival time becomes later and later, the probability that the delay is due to an incident increases. On a given link, the probability of an incident is computed as follows: p(Inc) = 0 if all vehicles arrive within their expected arrival time
OR
p(Inc) = [1- p(FA1) x p(FA2) x ... x p(FAn) where: p(Inc) = the probability that an incident has occurred on the link p(FAi) = the probability that late vehicle I is a false alarm
The algorithm will issue a false alarm when no incident occurs but when a predefined number of vehicles arrive late at the downstream detector, or if a tagged vehicle exits the link before reaching the downstream detector. Therefore:
p(FAi) = p(that a vehicle exits) + [p(that a vehicle does not exit) x p(that the late vehicle is not delayed by an incident)]
The probability that a vehicle exits is calculated by the system for each 15-minute period of the day for weekdays, Saturdays, Sundays, and holidays. The equation above can be rewritten as:
p(FAi) = p(that a vehicle exits) + [{1 - p(that a vehicle exits)} x p(that the late vehicle is not delayed by an incident)]
The algorithm requires historical data for the link travel time, travel time standard deviation, and the probability of a vehicle exiting the link before the downstream station. The user specifies the standard deviation multiplier and the number of steps over which to decrement the probability that a late vehicle is not delayed by an incident. Thus for each 15-minute period of each type of day, the system maintains a historical mean link travel time and travel time standard deviation for every link in the system. When the elapsed travel time on a particular link is greater than the historical mean travel time plus a user-specified number of standard deviations, the vehicle is “late”. Once a vehicle is declared late, the probability that it is not delayed by an incident is decreased from 1 to 0 over a prespecified number of standard deviations. Therefore, as the standard deviation of travel
E-21 time between stations becomes smaller, the probability that a “late” vehicle is not delayed by a incident decreases more rapidly. In other words, the probability that an incident caused a vehicle to be late increases faster for a link with (traditionally) uniform speeds.
Parkany and Bernstein (15) have recently developed a set of algorithms for AVI-based incident detection. In addition to a travel time algorithm used by the TRANSMIT system, they have generated two other pattern-based algorithms involving lane switching and lane monitoring. Since AVI is capable of providing such vehicle-specific information as lane changes, the lane switching model tracks the number weaving maneuvers between the upstream and downstream detector. It assumes that a large number of lane switches noted from one reader to the next is indicative of unstable traffic conditions. If the number of lane changes exceeds a threshold value, calibrated on a zone by zone basis, a incident is declared. The principle behind the lane monitoring algorithm is to track (over two or more time intervals) the vehicles in each lane that pass by at a reader location. If fewer vehicles pass in a certain lane than expected, the other lanes are checked to see if more vehicles than usual have passed. Rerouted vehicles may be indicative of an incident. If the number of vehicles in the outer lane dip below a calibrated threshold, the algorithm checks the traffic flow on the inner lane. If the inner lane volume exceeds an upper threshold, the algorithm declares an incident. Preliminary results obtained from traffic simulation models indicate that these pattern- based AVI detection algorithms compare favorably with the California loop detector algorithm. The results are shown in table 3 below.
Table 3. Comparison of AVI Detection Algorithms With Loop Detector Algorithms.
Algorithm Detection Rate False Alarm Rate Detection Time (percent) (percent) (minutes) Travel Time 75 1.9 2.0 Lane Switching 94 1.0 2.9 Lane Monitoring 92 3.3 1.7 California #7 53 1.6 2.2
E-22 PUBLIC AND PRIVATE COSTS FOR INCIDENT DETECTION
Michalopoulos and Anderson (16) have investigated the costs associated with loop detector installation as practiced by the Minnesota Department of Transportation (MnDOT). Their results are based on a loop detector system installed in 1993 along Trunk Highway 36 north of St. Paul. The primary components of the loop detector station were the loop itself, lead-in wire, detector amplifier cards, input file to hold the amplifier cards, and Type 170 traffic signal controllers which processed and transmitted detection data back to MnDOT’s Traffic Management Center. Each furnished and installed loop cost $560, two conductor No. 14 lead-in wire cost $0.63 per foot, and the loop detector amplifiers were $153 each. These prices, which include materials and labor to install, are in 1993 dollars. Traffic control costs were given as $40 per installed loop based on previous MnDOT project costs. The authors characterized these items as the Basic Direct Install Costs.
The authors noted an addition item in their study. Since the loop installation required the closing of 200 - 1200 ft of freeway lane for two hours and because the work was performed during daylight hours(9:00 to 14:00), the user delay for the detector stations was computed using the KRONOS Freeway Simulation Package. User delay forms an indirect cost to the motorist in terms of wasted fuel, higher vehicle repair costs and the lost opportunity of pursuing more productive endeavors. The User Delay Cost was estimated as $10.64 per vehicle-hour based on a 1987 study by the Federal Highway Administration and was adjusted for inflation at four percent per year.
Loop Detection Costs
The KRONOS simulation provided the delay and fuel consumption estimates shown in table 2. An estimated two-lane highway capacity of 4,800 vehicle per hour and constricted capacity of 1,500 vehicles per hour were specified for the simulation. The restricted capacity reduction of 68 percent was derived from the Traffic Engineering Handbook, 4th edition, Institute of Transportation Engineers, edited by J.L. Pine and published by Prentice Hall. While it could be argued that by installing loops at night these costs could be eliminated, note that the actual loop installation occurred during daylight hours. The objective of this comparison was to derive both direct and indirect costs based on actual field observations.
An examination of table 2, shown below, reveals that the total delay for installing six loop detectors is 3853 vehicle-hr per lane. Assuming that the delay cost to the motorist of $10.64 per vehicle-hour is a reasonable figure, the installation of six loop detectors cost $40,800 per lane. For a facility with loops installed in every traffic lane, as in the Los Angeles incident detection system (2), the User Delay Cost for a 4-lane freeway would exceed $163,000. On a per mile basis, the User Delay Cost is approximately $46,600 for loop detectors spaced every ½ mile. The report further states that the direct, out-of-pocket cost of installation for 54 loops was slightly less than $70,000, or $1300 per loop. For a 4-lane highway with loop detectors set every half mile and a detector in each traffic lane, the direct installation cost is $10,400 per mile.
E-23 Table 4. Simulated Results for Installation of Six Loops in One Freeway Lane (15).
Length of Roadway in Study Area: 18,450 ft (3.5 miles) Lane Closure per Loop: 2 hours required for installation (200 - 1200 ft of lane closed)
Simulation Run Total Travel Travel Time Ave. Speed Delay * Fuel Use (vehicle-mi) (vehicle-hr) (mph) (vehicle-hr) (gal) BASELINE 57000 918 62 0 3593 (no lanes closed) CONSTRUCTION 54825 2071 26 1014 3921 Day #1 CONSTRUCTION 59433 3805 16 2583 5323 Day #2 CONSTRUCTION 57914 1225 47 256 3782 Day #3 * Delay computed only for vehicle speeds under 40 mph
Installation Cost for loop detection: $10,400 per mile User Delay Cost for loop detection: $46,600 per mile
ETTM Detection Costs
ETTM detection costs are very difficult to quantify. It is important to note that costs will vary significantly by region and location throughout the United States and Canada. In addition, the AVI readers are not uniformly spaced along a highway but vary between two and four miles. Batz and Tarnoff have estimated the installation cost for AVI reader at $23,000 to $40,000 per unit (17). Assuming an average spacing of three miles and a maintenance cost, quoted by Pietrzyk (13) of $4,200 per unit per year, the cost per mile for ETTM incident detection is $29,400 per mile (both directions). ETTM installation costs in Houston vary between $50,000 and $60,000 per unit (18). Given the spacing and maintenance costs above, the costs per mile for Houston’s incident detection system is $34,000 per mile. Ullman, et al have estimated the cost of Houston’s system (with readers spaced every 2 to 4 miles) at a cost of $18,000 to $25,000 per kilometer or $29,000 to $40,000 per mile (19). The cost to equip a vehicle with a transponder is generally around $50 (13). A large urban area with 40,000 AVI-equipped vehicles increases the cost of ETTM incident detection by $2 million.
E-24 CONCLUSIONS
A cost comparison of loop versus ETTM detection systems should consider both direct costs and indirect costs. Direct costs are paid at the time of installation by the operating authority and as equipment maintenance costs over a period of years. These costs are in the form of a tangible monetary payment between parties. Indirect costs are paid by the users of a facility over an extended period of time. They do not involve a direct monetary payment between parties but are borne by the users as wasted time, wasted fuel, and decreased air quality.
In a comparison of direct, or out-of-pocket, costs loop detectors offer significant savings to the operating authority. Installation costs for a loop detector system is $16,000 per mile while the cost for ETTM incident detection is roughly $30,000 per mile.
However, when indirect costs resulting from motorist delay and wasted fuel are added to the direct cost of loop installation, the total cost per mile for a loop detection system rises to over $60,000 per mile. ETTM incident detection can offer significant savings to the public if the traffic authority is willing (and can afford) to shoulder the extra out-of-pocket expense for installing ETC roadside readers.
E-25 RECOMMENDATIONS
• ETC systems should be implemented in the design of all new toll facilities. Dedicated lanes should be separated from the conventional toll plaza lanes at some distance upstream and downstream of the toll booths. The toll authority should plan five conventional toll booths for every highway lane serviced. When the flow rate exceeds 5,000 vehicles per hour and the penetration rate of toll tag vehicles is above twenty percent, the toll authority can reserve three toll booths for every highway lane serviced at a ratio of roughly two conventional lanes for every dedicated AVI lane. Mixed use lanes should be avoided.
• In areas where electronic toll collection exists, or is planned, traffic managers should investigate the feasibility of electronic toll and traffic management systems as a means of incident detection. The reliability of ETTM incident detection algorithms is comparable to that of loop detection algorithms and ETTM can provide travel time and origin/destination data for planning purposes.
• Traffic managers should develop a network of contacts among police officials, city maintenance crews, and highway service patrols for the reporting of incidents. Existing incident detection algorithms fail to recognize a significant portion of highway incidents and can results in a number of false alarms if the algorithm is improperly calibrated. The combination of a detection algorithm with human information sources forms a powerful combination of congestion management tools.
• ETTM incident detection should not be used unless an electronic toll system exists in the area. The public will be reluctant to participate in a program without receiving some form of tangible benefit in return. An electronic toll collection system working in conjunction with an ETTM incident detection system provides an incentive for public participation by reducing motorists’ travel time on toll facilities. No incident detection system can be effective without the active support of the public.
E-26 ACKNOWLEDGMENTS
This report was prepared for CVEN 677, Advanced Surface Transportation Systems, a graduate course in transportation engineering at Texas A&M University under the direction of Dr. Conrad L. Dudek. The professional mentors for this course were Walter M. Dunn, Ginger Gherardi, Leslie N. Jacobson, Jack L. Kay, Colin A. Rayman and Thomas C. Werner. The author would like to thank all of the mentors for their guidance and expertise. Special thanks go to Mr. Thomas C. Werner, P.E. for his help and insight in writing this paper. The author would also like to thank those professionals that provided further information for this paper: William McCasland and Mike Strech.
E-27 Bowman Kelly received his B.S. in Civil Engineering from the University of North Carolina at Charlotte in August 1995. He is currently pursuing his M.S. in Civil Engineering at Texas A&M University. Bowman has been employed by the Texas Transportation Institute since September 1995 as a Graduate Research Assistant. University activities he has been involved in include: the Institute of Transportation Engineers and the American Society of Civil Engineers. His areas of interest include: geometric design and route surveying.
E-30 E-31 BARRIERS TO IMPLEMENTATION OF SIGNAL PRIORITY SYSTEMS FOR TRANSIT OPERATIONS: LESSONS LEARNED FROM ADVANCED TRAFFIC MANAGEMENT SYSTEMS
by
David A. Noyce, P.E.
Professional Mentors Walter M. Dunn, Jr., P.E. Dunn Engineering Associates
and
Thomas C. Werner, P.E. New York State Department of Transportation
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas 77843
August 1996 SUMMARY
Traffic signal priority systems for transit operation have been shown to be an effective method of improving the efficiency, operation and attractiveness of transit. It is the hope of transit officials that by improving transit, ridership will increase as more people leave their private vehicle at home in favor of transit. Increased ridership can also lead to reductions in traffic congestion and environmental degradation. Yet, despite these benefits, many transit agencies and city traffic engineers around the country are resistant to implementing these techniques. This report provides a detailed investigation of traffic signal priority systems for transit vehicles and the many barriers faced when attempting to implement a signal priority system. Characteristics and guidelines necessary for successfully implementing a signal priority system are established. This report concludes by providing and evaluating strategies for overcoming the many barriers to implementation.
The concept of signal priority systems for transit operation has been in existence since at least the 1960's. Transit priority demonstration projects were applied at various locations around the country with none of the installations enjoying a prolonged life. Recent advances in technology along with increases in traffic congestion have brought the transit priority issue back to the forefront. Signal priority for transit vehicles can be implemented in many ways ranging from simply adding a few more seconds of green time to the transit phase to a complete signal preemption for the transit vehicle. The latter require a means of detecting the location and approach of a transit vehicle through either inductance loop detection, a signal emitter/detector system or AVI (Automatic Vehicle Identification) technology. Various techniques have been developed to successfully call for and release the request for transit priority. A wide array of performance measures, design guidelines, and system criteria must be evaluated to assure the viability of a transit signal priority system.
A detailed review of the technologies available for transit signal priority and interviews with transit agencies and professionals throughout North America have led to the identification of a wide array of potential barriers to implementation. These barriers range from institutional and agency considerations to operational and human factor constraints. Financing and the decreasing amounts of FTA (Federal Transit Agency) support can be one of the most significant barriers to implementation. This is not surprising as funding issues impact every local, state and federal agency. Once a funding source has been identified, other potential barriers related to agency coordination, transit operations, and priority system implementation become more diverse and include unique factors for each jurisdiction. Overcoming these barriers require educating both the appropriate agency and city staff as well as the public so that the concept of signal priority systems is well understood. Many transit agencies have found that the lack of knowledge and understanding of priority systems by the people who desire transit priority has played a significant role in delaying or preventing the implementation of a priority system. It is also advantageous to show that the priority system will work effectively under the proposed scheme before the system is implemented. Recent advances in simulation technology have allowed computer simulation of signal priority systems to become a tool for overcoming this barrier. If signal priority is a feasible alternative for a given transit system, identifying the barriers to implementation, developing strategies for overcoming these barriers, and following characteristics and guidelines established by successful priority systems will allow signal priority for transit operations to be successfully implemented.
F-ii TABLE OF CONTENTS
INTRODUCTION ...... F-1 Objectives ...... F-2 Scope ...... F-3 Method of Study ...... F-3 Literature Review ...... F-3 Data Collection ...... F-3 Organization of Report ...... F-4
BACKGROUND ...... F-5 Transit Signal Priority in Europe ...... F-5
SIGNAL PRIORITY CONTROL STRATEGIES ...... F-8 Definition ...... F-8 Partial and Full Priority Methods ...... F-8 Priority Methods ...... F-9 Green Extension ...... F-9 Red Truncation ...... F-9 Red Interruption ...... F-9 Lift Strategy ...... F-9 Queue Jumping ...... F-11 Stream Weighting ...... F-11 Phase Suppression ...... F-11 Window Stretching ...... F-12 HOV Weighted OPAC ...... F-12 Conditional Priority ...... F-12 Other Methods ...... F-13 Transit Vehicle Detection ...... F-13 Priority Methods in Selected Cities ...... F-13
STUDY DESIGN ...... F-15 Signal Priority System Manufacturers Interview Results ...... F-16 Transit Agency and Professionals Interview Results ...... F-17
BARRIERS TO IMPLEMENTATION ...... F-18 Institutional/Agency Considerations ...... F-18 Operating Agency Cooperation ...... F-18 Financial Considerations ...... F-20 Liability ...... F-21 Public Support ...... F-22 Project Champion ...... F-22 Operational Considerations ...... F-22 Cross-Street and Intersection Volumes ...... F-22 Level of Congestion ...... F-23
F-iii Delay ...... F-24 Traffic Signal Operations ...... F-25 Transit Operator Control ...... F-26 Signal Priority Methods ...... F-28 Hardware/Software Constraints ...... F-28 Transit Density ...... F-29 Intersection Spacing and Transit Stop Locations ...... F-29 Basic Geometry ...... F-30 System Operation ...... F-30 Transit System Operators ...... F-36 Human Factors ...... F-36 Allowable Minimum Green Phases ...... F-36 Pedestrian Constraints ...... F-36 Driver Expectancy ...... F-37 Safety and Fail Conditions ...... F-37 Enforcement ...... F-38 Compatibility ...... F-38 Barriers to Implementation Matrix ...... F-38
EVALUATING NEW/PROPOSED TRANSIT PRIORITY SYSTEMS ...... F-40 Simulation of Proposed Systems ...... F-41
CHARACTERISTICS/GUIDELINES FOR IMPLEMENTATION ...... F-43 Transit Organization ...... F-44 Transit Type ...... F-45 Transit Network Characteristics ...... F-45 Level and Type of Transit Service ...... F-46 Stop/Station Characteristics ...... F-47 Traffic Characteristics ...... F-48 Signal Control System ...... F-49 Transit Identification System ...... F-49
STRATEGIES FOR OVERCOMING BARRIERS TO IMPLEMENTATION ...... F-51 Strategies ...... F-51
CASE STUDY: KING COUNTY, WASHINGTON ...... F-55 Application of Strategies for Overcoming Barriers to Implementation ...... F-55 Summary ...... F-60
CONCLUSIONS ...... F-60
ACKNOWLEDGMENTS...... F-61
REFERENCES ...... F-62
F-iv INTRODUCTION
The Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), the Clean Air Act of 1990 (CAA), and the emerging concept of sustainable transportation are placing heavier demands on public transit systems to meet mobility and environmental goals. Because of this, transit system operators in major cities throughout the United States are looking for ways to make transit more attractive to the public. Recent advances in the transportation industry such as alternative fuel vehicles and Intelligent Transportation Systems (ITS) technology have taken large steps in improving the reliability and efficiency of transit systems (1). It is the hope of transit system operators that by increasing the attractiveness of the transit system through improved reliability and efficiency, ridership will increase as motorists are enticed to leave their personal vehicles in favor of the transit system. Bus and light rail transit (LRT) serve as the principle sources of surface public transit in most cities. Bus transit consists of rubber-tired vehicles using the existing roadway network and has the advantage of flexibility and diversity in travel routes. The loading and unloading of bus passengers can take place at curbside locations or at park-n-ride facilities and does not require the construction of special loading platforms. LRT are train-type vehicles that travel on rail guideways. LRT travel is limited to the available rail infrastructure in place and usually requires the construction of special loading platforms for passengers. Both transit types can carry large volumes of passengers during the peak-hour as well as during other periods of the day. Despite their importance and significantly larger person-per-vehicle occupancy, both bus and LRT must compete with automobile traffic within the traffic stream and at signalized at-grade intersections. No special treatment is given to these vehicles as single occupant vehicles, buses, and LRT are all weighted equally. Typical bus and LRT vehicles are shown in Figure 1.
Bus Transit (3) LRT (52)
Figure 1. Transit Types.
F-1 To overcome this dilemma, traffic signal priority schemes using advanced traffic control (ATC) systems have been considered. ATC systems provide traffic responsive/traffic adaptive dynamic signal phasing operation that can be designed to favor transit vehicles. Through a series of sophisticated algorithms within the traffic signal controller, along with upstream detection devices, ATC with signal priority attempts to reduce or eliminate delay for transit vehicles at signalized intersections by temporarily altering the traffic signal phase through one of many potential treatments. Detection of the transit vehicle is completed by using either loop detectors, vehicle emitter/detection devices, radio signal identification, or AVI. AVI is the most technologically demanding method as it provides automatic position-tracking and status monitoring of individual transit vehicles throughout the entire fleet. Using full signal priority, an approaching transit vehicle that is appropriately detected receives a green phase when it arrives in lieu of other demands currently placed on the intersection. This reduction in total delay to the transit vehicle through the use of traffic signal priority can decrease transit travel time which may ultimately make the use of transit more attractive to the public.
One of the largest current applications of signal priority in the United States is the Automated Traffic Surveillance and Control (ATSAC) system in Los Angeles. Through a series of inductance loop and video detection devices, transit vehicles are recognized as they approach the signalized intersection and given priority with the objective of minimizing travel time and delay. Transit priority systems have also been successfully implemented in Portland, Seattle, San Diego, Toronto and other cities in North America. These projects continue to demonstrate that transit travel time and delay can be significantly reduced through signal priority systems. Many of these projects also show that improved transit performance can lead to increases in ridership. Other successful projects using transit signal priority methods have been observed throughout the world in such places as Australia, using the signal priority methods within the Sydney Coordinated Adaptive Traffic System (SCATS), and in the United Kingdom using transit priority within the Split Cycle Offset Optimization Technique (SCOOT) (2). Despite these demonstrated successes, many transit agencies and cities continue to reject opportunities for implementation of a traffic signal priority system for transit vehicles. A recent study conducted by the Texas Transportation Institute found that only 6 out of 125 transit agencies responding to a survey used signal priority for bus transit operations (3). The reasons why many transit agencies and cities resist the implementation of transit signal priority systems and the barriers that are in place to prevent the implementation of these systems are not well understood.
Objectives
The objectives of this research are as follows:
1. Identify barriers to implementation of signal priority systems for transit operations through lessons learned from successful and unsuccessful applications of signal priority systems.
2. Identify significant factors necessary for a successful signal priority system for transit.
3. Develop strategies for overcoming the barriers to implementation.
F-2 Scope
The scope of this research will include a review of the literature related to ATC systems with emphasis placed on ATC applications related to traffic signal priority systems. Manufacturers of priority signal control systems will be contacted to obtain a thorough understanding of how they operate, what barriers are commonly encountered, the relationship to emergency vehicle priority systems, and locations of recent successfully and unsuccessfully installed priority systems. Key people in North America who have knowledge directly related to transit signal priority systems that are currently in operation will be interviewed. Interview questions will focus on lessons learned from successfully and unsuccessfully implemented transit signal priority systems, guidelines and criteria for signal priority system installation and ways to overcome the many barriers to installation. The four primary locations/sources of information will be the ATSAC system in Los Angeles, King County Transit in Seattle, Tri-Met Transit in Portland, and the Toronto Metro Transit System in Toronto, Ontario.
Method of Study
Literature Review
A state-of-the-art literature review was conducted to establish background information on transit signal priority systems. Included in this literature review were proprietary reports on the implementation and operational results of a number of transit priority systems currently in place. Information related to current technologies and the types of systems being used along with the priority and preemption methods being implemented were also reviewed. The literature review for this research included over 80 articles from sources both within and outside of the United States.
Data Collection
Data collection took place in the form of telephone interviews. In addition, numerous pieces of documentation and brochures provided by these individuals were collected and employed. The telephone interviews targeted a diverse group of professionals with knowledge related to signal priority systems and were designed to fill the informational voids that existed in the literature. The target groups of professionals were classified into one of the following three categories:
1. Signal priority system manufacturers;
2. Transit agencies considering the installation of signal priority systems for transit; and
3. Professionals with knowledge of signal priority systems for transit.
Table 1 lists the organizations represented by the individuals interviewed.
F-3 Table 1. Contacted Agencies for Interview.
Agencies Considering System Manufacturers Transit Priority Systems Transit Professionals Opticom, 3M Traffic Control King County Transit, City of Portland, Systems, St. Paul, MN Seattle, WA Portland, OR Sonic Systems Corporation, Capital Metro, Metro Toronto Transit, Vancouver, BC Austin, TX Toronto, ON PreEmption Marking Los Angeles Department of Incorporated, Scottsdale, AZ --- Transportation (LADOT), Los Angeles, CA Optronix, Phoenix, AZ --- Federal Transit Agency, Washington, D.C. ------JHK Associates, Los Angeles, CA ------PB Farradyne, Seattle, WA ------King County Transit, Seattle, WA ------FHWA, Washington, D.C. ------Texas Transportation Institute, College Station, TX ------Kitsap Transit, Seattle, WA -- --- JRH Associates, Eugene, OR
Organization of Report
The report is divided into nine sections. Section 1 includes the introduction to the report. Section 2 provides background information on signal priority systems for transit including a review of a number of European systems. Section 3 provides a detailed review of signal priority methods as well as vehicle detection techniques. A review of signal priority for transit used in cities throughout North America is also included. Section 4 includes a description of the study design and the interview questions commonly asked. Section 5 presents a detailed description of the important factors related to the implementation of a signal priority system for transit and presents a barrier to implementation matrix developed to highlight many of the significant factors. Section 6 provides a number of performance measures and site considerations that should be reviewed when evaluating a new or proposed signal priority system for transit. Section 7 develops a comprehensive list of characteristics and guidelines necessary for implementation of a signal priority system. Section 8 provides strategies for overcoming the many barriers to implementation of signal priority systems for transit operations. Section 9 applies these strategies developed to a case study in Seattle, Washington. Finally, conclusions are presented based on the data, analysis and guidelines developed.
F-4 BACKGROUND
Signal priority systems designed to reduce delay and improve the efficiency of transit operations in the United States have been of interest since at least the late 1960s. A surge of activity occurred in the 1970s as a result of the energy crisis which led to a multitude of experiments with bus priority in a number of U.S. cities (4-7). None of the experimental systems however led to a sustained existence. Each of these systems fell out of service primarily as a result of the failure to strike a balance between adequately providing for the needs of general traffic while concurrently providing sufficient benefits to transit to make the system cost-effective (8). Also, the lack of appropriate technology to make the priority systems feasible and a general lack of sufficient commitment to the priority philosophy on the operational and management level accelerated the deactivation of the systems.
Although specialized signal controls are used for transit priority in Europe today, a number of factors have thus far prevented their widespread application in the United States (9). These factors include a lack of the appropriate technology to implement an effective priority system in a cost-effective manner, a lack of standards and warrants, the detrimental effects of inefficient priority systems on cross-street and coordinated traffic, and a lack of simulation methods to determine the effectiveness of a signal priority system before its implementation. The European experience suggests that signal priority for transit remains a viable technology and, if implemented properly, can result in significant reductions in transit delay and reduced travel times without greatly affecting cross-street traffic. The viability of signal priority for transit is further emphasized by recent advances in vehicle detection technology, the advent of ITS, and at least four systems that are currently operating with success nationally. Today, the combination of technology and experience have made signal priority for transit operation a more viable tool than at any time in the past.
Transit Priority in Europe
Improving public transport services in urban areas is increasingly seen as an important element in the fight against traffic congestion and environmental degradation in Europe (10-12). This requires not only improved frequency and quality of service, but also the provision of signal priority systems to reduce delay and improve transit regularity. Much of the attention is now focused on the use of real-time traffic control systems to provide transit signal priority.
One of the current projects in Europe is the PROMPT (Priority and Informatics in Public Transport) project. PROMPT has been involved in the development, implementation, and evaluation of real-time public transport priority within advanced UTC (Urban Traffic Control) systems. In London, England, the real-time UTC system is under SCOOT (Split Cycle Offset Optimization Technique) control. Transit priority has been introduced into SCOOT by developing and implementing new logic for providing green time extensions or recalls according to the spare green time available on non-priority phases. This logic is based on the difference between the actual degree of saturation on intersection approaches and a target degree of saturation which is user defined and can therefore be varied according to the relative effects desired for buses and other traffic. Transit priority is activated by using transponders in each transit vehicle and inductive loop detectors located between 70 and 100 meters upstream of the intersection. Priority extension
F-5 facilities can be initiated either centrally by SCOOT, on detection of a transit vehicle, or locally by the controller subject to authority from SCOOT. Local extensions avoid the 4 to 5 second communication delays incurred when decisions are centralized, a common problem with SCOOT. The SCOOT system has also been developed to accept other vehicle detection techniques such as AVI technology.
In Turin, Italy, the UTOPIA (Urban Traffic Optimization by Integrated Automation) traffic control system is used. UTOPIA is a traffic responsive UTC system based on a hierarchical concept where local intersection control operates within a reference plan established by the central control system. The basic idea behind UTOPIA is to provide absolute priority to selected transit vehicles while optimizing the movement of all vehicles at the intersection. The control system incorporates communications between intersections and a rolling horizon control algorithm so that signal decisions consider traffic predictions for the next two minutes. This predictive control incorporates transit signal priority so that traffic signals are already adjusting for transit vehicles two minutes away from the intersection, based on predicted travel times. This is achieved through the city’s AVM (Automatic Vehicle Monitoring) system, which also holds the transit schedules for all tram and bus routes, and through algorithms developed to determine priority requirements according to “adhering to schedule” or “headway variability.” Selective priority requests are then passed from the AVM system to the UTC central control for subsequent implementation at the appropriate intersections. The PROMPT organization has worked with Turin to enhance the existing priority system, particularly through enhanced journey time prediction algorithms, and to develop new techniques for applying priority features within the overall fleet management.
Gothenburg, Sweden incorporates approximately 20 coordinated signal systems, each containing between four and ten signalized intersections, into a master controller choosing a signal timing plan based on traffic counts. Nearly all of the 85 signalized intersections with tram traffic have absolute tram priority using vehicle location through inductive loop detectors positioned between 100 and 200 meters upstream of the stop line. When a tram is detected, the relevant traffic signal goes green as soon as possible. The signal remains green until the tram crosses another loop detector as it passes the intersection.
Specific quantitative operational information was not determined for the Gothenburg, London or Turin system. However, a number of significant criteria can be identified. A comparison summary of the Gothenburg, London and Turin system is presented in Table 2.
F-6 Table 2. Transit Priority System Comparison (10 - 12).
Location Characteristic London Turin Gothenburg Control System SCOOT UTOPIA Plan Selection Transit Type Buses Only Trams and Buses Trams and Buses Transit Detection Inductive Loops AVM Inductive Loops and AVM Priority Allocation All Buses Selected Vehicles All Equipped Vehicles Upstream Detector 70-100 meters --- 100-200 meters Loop Location Number of Transit Vehicles with 1000 1300 N/A Detection Devices Number of Intersections with 60 140 85 Transit Priority Systems Traffic Congestion High Moderate Low Transit Volume High Moderate Low
F-7 SIGNAL PRIORITY CONTROL STRATEGIES
An in-depth understanding of the various signal priority control strategies for transit operations is required before an analysis of the barriers to implementation of signal priority systems can be completed. This section presents an overview of signal priority control strategies and their application to transit operations.
Definition
Signal priority is an attempt to reduce or eliminate delays for transit vehicles at an intersection by temporarily altering the traffic signal phase so that an approaching transit vehicle receives a green indication when it arrives (2). Attempts have been made to use signal coordination and move vehicles through a series of intersections in platoons; however, the variation in average travel speeds between transit and non-transit vehicles and the necessity for transit vehicles to stop for patrons has most often made this method ineffective. Signal priority control strategies define the conditions and duration of a priority treatment for transit at a signalized intersection.
Partial and Full Priority Methods
Transit priority treatments generally consist of two levels: partial and full priority. Partial priority is a method of widening the green window for transit at a traffic signal through one of a number of potential methods. The green window can be thought of as the amount of time in the signal cycle during which a transit vehicle can pass through the intersection. The window will most often coincide with the green time provided for parallel non-conflicting traffic movements. A wider window reduces the probability that the transit vehicle will have to stop.
Partial priority attempts to minimize disruptive effects on road and pedestrian traffic. If the signals are operated in the coordinated mode, any additional time given to the transit vehicle must be taken away from other phases in the fixed cycle length. The amount of extra transit phase length would be limited, and no phase with a demand would be skipped in any cycle. The shortening of phases would not violate any minimum times preset in the controller, but pedestrian service could be suppressed if the signal operator permits. Partial priority treatments are often implemented using a form of "passive" priority (13). Passive priority treatments use a predetermined “knowledge” of public transit operations to determine the appropriate priority treatment. Some common passive priority treatments include reducing the cycle time, green phase weighting (adding seconds to the transit green phase), priority movement repetition in the cycle, and transit speed progression.
Full priority does everything that partial priority does and then goes one step further by allowing some non-transit phases to be skipped or eliminated to reduce the delay to transit (14). In the “pure” case of full priority, or preemption, transit priority overrides all other traffic demands at the intersection except emergency vehicles, subject only to the minimum clearance times. Through the use of "active" priority treatments, full priority uses detection technology to identify the location of a transit vehicle and implement the most appropriate priority method based on location and current signal phasing. Full priority provides the optimum operating conditions for transit, but can also lead to intolerable non-transit vehicle delay for side-street and left-turning traffic if used
F-8 indiscriminately. Full priority can cause signals operating in the coordinated mode to become out of step with other signals. Most priority control software provides for rapid recovery of coordination (usually in one cycle) but traffic progression can be disrupted during peak periods with short transit headways. Full priority may also cause excessive delay to traffic at congested intersections during peak periods. However, full priority may be appropriate at some intersections during off-peak periods with longer transit headways and lower vehicle volumes.
Priority Methods
A number of methods in obtaining signal priority for transit operations have been developed (2, 8, 14-20). The most common signal priority methods, currently used in providing transit priority, are discussed in the following sections.
Green Extension
Green extension consists of the elongation of the transit green phase time, by a fixed amount, as the transit vehicle approaches the intersection. This priority method is initiated when the time between detection and the arrival of the transit vehicle at the intersection is computed to be longer than the remaining green time on the transit phase. The transit vehicle would then be expected to arrive after the “normal” green phase and clear the intersection sometime during this green extension period. Green extension is shown in Figure 2.
Red Truncation
Red truncation allows premature termination of the red phase on the transit street accelerating the onset of the green phase. This early start of the green phase for transit allows the approaching transit vehicle to receive a green phase as it arrives at the intersection and can be implemented at an earlier time to clear the queue at the intersection before the transit vehicle arrives. Red truncation is shown in Figure 3.
Red Interruption
In red interruption, a short green phase, not contiguous with the adjacent green, is injected within the red phase on the transit street. Red interruption is shown in Figure 4.
Lift Strategy
When the transit vehicle is identified for priority by the upstream detection equipment, the controller responds by placing a hold on all other detection calls at the intersection. This “lifting” (ignoring) of detection calls on all opposing phases, after servicing the minimum clearance times, provides a quick return to the transit phase. The operation of this system requires actuated signal control.
F-9 Figure 2. Green Extension.
Figure 3. Red Truncation.
F-10 Figure 4. Red Interruption.
Queue Jumping
Stop bar detection of transit vehicles by AVI or inductance loops can provide a special transit only advanced green so that the transit vehicle can get an early release or “jump” from the intersection. The queue jump method is only applied to bus transit operations. This jump allows the transit vehicle to proceed in front of the parallel stopped queue and primary vehicle platoon. This strategy generally requires special intersection geometry (e.g. a separate bus lane; nearside transit stops) and is considered most effective in areas of high congestion levels.
Stream Weighting
Stream weighting is applied by increasing the maximum green time for selected approaches. This method is implemented on a time-of-day basis with optional reduction in maximum green times for the other non-priority approaches. Stream weighting is commonly applied in high congestion priority systems. No detection devices are required for the implementation of this strategy.
Phase Suppression
Where non-transit movements are accommodated during more than one phase of the signal cycle, one of these phases can be suppressed or skipped to get back to the priority transit phase in a more rapid manner. This technique allows the controller to skip back to the transit phase in a predetermined method when a call for priority has been detected.
F-11 Window Stretching
Window stretching is a method of providing an active priority treatment in a coordinated system location. Using the window stretching method, the signal cycle is divided into two durations consisting of the main street or transit period and the cross-street period. The transit period or "green window" is stretched, through either green extension or red truncation, taking time away from the cross-street period to provide a larger green window for the transit vehicle to pass through the intersection. A core phase is maintained in both the main street and cross-street periods to assure continued progression on the transit route. The concept of window stretching is shown in Figure 5.
HOV Weighted OPAC
Optimized Policy for Adaptive Control (OPAC) is a computational strategy for real-time demand responsive signal control which can be programmed to be person responsive (8, 15). OPAC features a dynamic optimization algorithm using real-time data to determine the desired traffic signal operations. The location of the transit vehicle and need for priority are continually monitored through the use of an AVI system. Introducing real-time data along with AVI technology allows the priority algorithm in the controller to maximize mobility at the signalized intersection.
Conditional Priority
One way to introduce the benefits of signal priority without some of the potential drawbacks is to implement conditional priority schemes (15, 21). Under conditional priority, the same priority is implemented but only if the transit vehicle is determined to be behind schedule. Conditional priority requires AVI technology for locating vehicles and transit schedules throughout the network.
Figure 5. Window Stretching Signal Timing Concept for Main Street Signal (22).
F-12 Other Methods
Numerous other signal priority methods for transit vehicles can be developed using parts or combinations of the methods described. Exact or hybrid forms of green extension, red truncation, and red interruption are reportedly the most common methods in use today.
Transit Vehicle Detection
The signal priority system often includes some form of detection devices that sends a message to the traffic control system requesting priority as the transit vehicle approaches the intersection. The primary methods of detection include inductance loop detectors, emitter/detector systems using either infrared light or sound, radio-based systems, and AVI. Loop detectors are generally placed in groups of two, with one detector upstream to call for priority and one detector at the intersection to cancel the call. The emitter/detector systems have an emitter attached to the transit vehicle that is detected by a receiving device at the intersection which in-turn sends a message to the controller requesting priority. Radio-based systems are more commonly used for emergency vehicle detection and priority and have limited use for transit. AVI technology provides the most sophisticated detection method available as transit vehicle locations are monitored and information is exchanged during all times. The ability to monitor transit operations through AVI allows additional flexibility in the selection of the priority method. Additional information related to loop detectors, and the emitter/detector systems are provided in the following sections of this report.
Once the transit vehicle is detected, the traffic control system then determines if priority is warranted and which priority method is the most appropriate. Unlike AVI technology, signal priority control strategies can vary from intersection to intersection and still provide a seamless operation between different jurisdictions and transit agencies. Regardless of the priority control strategies implemented, the result is an increase in green time along the transit route reducing the amount of delay experienced by the transit vehicle.
Priority Methods in Selected Cities (23)
Table 3 provides a brief overview of the level of signal priority methods used by LRT systems in North America. The vertical direction of Table 3 is scaled to represent the level of signal priority given to the transit vehicle. For example, cities listed near the top of the table apply full signal priority while cities listed at the bottom of the table provide no signal priority for transit. The table also provides columns representing the location of the LRT within the road right-of-way. Many of these cities listed provide similar signal priority applications for their bus transit systems.
F-13 Table 3. Traffic Signal Priority Levels in North American Cities (23).
Level of Signal LRT Location within Road Right-of-Way Priority Side Median Mixed Traffic Exclusive Lane Full LRT Buffalo Calgary Priority Calgary Edmonton San Diego Sacramento San Diego Los Angeles
Pittsburgh Portland Portland Calgary Toronto Dallas
San Jose Sacramento Sacramento Partial LRT Los Angeles Priority
San Jose
New Orleans
New Orleans San Francisco San Francisco No Transit Boston Philadelphia Philadelphia Priority Cleveland Boston Cleveland
F-14 STUDY DESIGN
As previously mentioned, the primary objective of this investigation was to identify barriers to implementation of signal priority systems for transit, identify characteristics and guidelines to determine if a transit signal priority system is worthwhile, and develop strategies for overcoming the identified barriers to implementation. The first step in meeting these objectives was to conduct a literature review. A thorough review of all available literature helped to develop a foundation of information to explain the priority system for transit concept and began to develop the information needed to meet the objectives.
The next step involved conducting interviews with transit agencies and professionals. The primary purpose of the interviews was to fill the informational voids found in the literature. Each person was contacted by phone and asked to answer a series of questions. They were also asked to send any literature or information that might be pertinent. Interviews with signal priority system manufacturers contained the following questions:
1. How do your signal priority systems work? 2. What is the cost of a typical installation? 3. What is the total number of signal priority installations placed by the company? 4. What is the total number of installations currently being considered? 5. How many different types of applications have been placed? 6. Are emergency vehicle/transit systems applied uniformly in each installation? 7. What are the traffic signal controller requirements necessary to operate the priority system? 8. Will you please send some literature and any technical publications on the system?
Interviews with other transit agencies and professionals contained the following questions:
1. Can you describe how the signal priority system works within the system you are most familiar? 2. Who receives priority? 3. How is the priority obtained? 4. What operational constraints allow/prevent the use of priority? 5. How is the system brought back to equilibrium after the priority movement is satisfied? 6. What was the cost of the system? 7. How many signals are in the system? 8. Why is the system successful/unsuccessful? 9. What were the barriers to installation? 10. What are the operational barriers/constraints? (consider all of the operational barriers identified) 11. What agencies are involved in the operation of the system? Do they work well together? 12. What human factor constraints are relevant to the signal priority system? How are they overcome? 13. How are the priority schemes enforced? 14. Is the signal priority system compatible with adjacent or future systems? 15. What advice would you give to a city that is considering the installation of a signal priority system?
F-15 The final step involved the development of a case study to validate the strategies for overcoming barriers to implementation developed as part of this investigation. King County Metro in Seattle, Washington was contacted to complete this effort.
Signal Priority System Manufacturers Interview Results
The following summarizes the results of the interviews with signal priority system manufacturers. Since only two different product technologies were developed by the four manufacturers contacted, only the light emitting (Opticom) and sound emitting (Sonic Systems) are presented.
Opticom and Optronix systems use infrared light, emitted from a device on the transit vehicle to a detection device, which initiates a call for signal priority (24). Sonic Systems and PreEmption Marking Systems are similar to the infrared system except for the fact that the transit vehicle emits ultrasonic sound waves to request priority (25). Table 4 provides a review of the interview responses to selected questions.
Table 4. Manufacturer Interview Results (24, 25).
Question Opticom Sonic Systems How does your system The Opticom system transmits The Sonic System transmits work? infrared light to provide line-of- ultrasonic sound frequencies detected sight communication only to the by an audio receiver mounted on a upcoming intersection in the transit signal pole or mast arm. A call for vehicle’s direction of travel. The priority is placed when the frequency light is detected and a call for and intensity of the sound matches priority is sent to the controller. predetermined constraints. Does the system Yes - Works for any vehicle with a Yes - Emergency vehicles require no operate effectively for transmitter. Emergency vehicles additional hardware. The siren acts both emergency vehicle and transit vehicles are assigned as the emitter. For transit, an and transit priority? different frequencies. ultrasonic sound emitter is required. What is the cost of a $1500 - $4500 per intersection; $4000 per intersection for detectors; typical installation $1000 per emitter $200 per emitter (transit only); $1300 (equipment only)? per intersection for visual verification What is the total Numerous - By far the most used Many in Canada. New system in the number of priority system in the U.S. Part of the 3M U.S. Currently in the introduction systems placed by your Corporation. Product has been in phase. company? existence for 25 years. What is the number of Many, all over the country. Many. Have the potential to install new priority systems systems in the near future in Austin, being considered? Texas, and in New Jersey.
F-16 Table 4. Manufacturer Interview Results (con’t.).
What are the traffic Requires wire and power to the Requires wire and power to the signal controller detectors. A card is added to the detectors. A card is added to the requirements for controller containing the priority controller containing the priority operation? logic and control algorithms. logic and control algorithms. Compatible with all traffic signal controllers. What are the products’ Well established and reliable. Can Can adjust detection sensitivity to strengths? use conditional priority methods. any distance desired up to 0.5 miles. Detection ranges are adjustable. Has a visual detection device so the Can add a white confirmation light operator knows priority is in place. to tell the transit operator that a Not affected by weather or physical priority call has been obstacles. No operator involvement. acknowledged. No emitter required for emergency vehicles. Has flexibility to provide data transmission (i.e., passenger counts, schedule data). What are the products’ All vehicles require expensive Unwanted signal priority can be weaknesses? emitters. Operation depends on initiated by an emergency or transit clear line-of-sight. Weather can vehicle that stops before the affect performance. Requires intersection. operator involvement in turning the emitter on and off when requesting priority. Additional Features? Capable of determining and Capable of determining and recording vehicle locations, times, recording vehicle locations, times, and other related data. and other related data. Barriers to Finances. Finances. Demonstrated Implementation? effectiveness of this technology.
Transit Agency and Professionals Interview Results
The information collected during the interview process with transit agencies and professionals provided answers to many of the questions that were void in the literature. The results of this interview process are used throughout the rest of this report in developing the ideas and concepts behind the barriers to implementation, characteristics, guidelines, criteria, and methods for overcoming the implementation barriers. Direct responses from the interview process will be referenced accordingly.
F-17 BARRIERS TO IMPLEMENTATION
The array of potential barriers to implementation are numerous but tend to fall into a number of general categories. Combined with each barrier are essential criteria that, in most cases, must be satisfied in order to implement a priority system. This section provides a detailed review of the many potential barriers to implementation of a signal priority system for transit vehicles. This combines information derived from the literature review, telephone interviews with priority system manufacturers and transportation professionals knowledgeable in transit priority systems and personal experiences. Table 5 provides an overview of the potential barriers to implementation of signal priority systems for transit.
Institutional/Agency Considerations
The initiation of new transportation strategies such as transit signal priority cannot begin without support from the agencies responsible for the operation of the transit system. Within each transit operating agency, a number of potential barriers were identified.
Operating Agency Cooperation
Korve and Jones, in a survey of transit agency operations, discussed the importance of operating agency cooperation with the following cities and transit agencies (26):
C Los Angeles (Metropolitan Transit Authority) C Sacramento (Sacramento Regional Transit District) C Portland (Tri-County Metropolitan Transportation District) C Philadelphia (Southeastern Pennsylvania Transportation Authority) C Edmonton (Edmonton Transit) C Calgary (Calgary Transit) C Cleveland (Greater Cleveland Regional Transit Authority) C Buffalo (Niagara Frontier Transit Metro System) C San Francisco (San Francisco Municipal Railway) C Baltimore (Maryland Mass Transit Administration) C Boston (Massachusetts Bay Transportation Authority) C St. Louis (Bi-State Development Agency) C Pittsburgh (Port Authority of Allegheny County) C San Diego (San Diego Metropolitan Transit Development Board) C San Jose (Santa Clara County Transportation Authority)
This list of cities and transit agencies comprises many of the major transit operators in North America, especially those who offer LRT operations. As expected, interjurisdictional cooperation and agreements were important to most of the agencies contacted. In locations where there is little overlap between facilities, the primary mode of cooperation is in the form of agreements reached for operational control and maintenance of each segment of the transit system. In locations where signal priority systems are in place for transit operation, the strategies of implementing priority must be
F-18 Table 5. Potential Barriers to Implementation.
Barrier Components Institutional/Agency Cooperation Operating Agency Cooperation Financial Considerations Liability Public Support Project Champion Operational Considerations Cross-Street and Intersection Volume Level of Congestion Degree of Saturation Delay Traffic Signal Operations Transit Driver Control Signal Priority Methods Hardware/Software Constraints Bus Delay Intersection Spacing Basic Geometry System Operation Transit Stop Locations Traffic System Operators Human Factors Allowable Minimum Green Times Pedestrian Constraints Driver Expectancy Fail Conditions Enforcement Enforcement Compatibility Compatibility
F-19 agreed upon by all relevant parties and the responsibility of maintaining the system is delegated prior to integration into the existing traffic signal system.
Institutional relationships and related negotiations are reported to be most critical when the LRT and related transit operations are in their first years of (at-grade) operation and where growth in traffic and expansion of the LRT system is anticipated (26). The quality of the institutional relationship determines whether critical intersection issues such as signal priority schemes can be resolved and the time frame typical for resolution of issues. These interjurisdictional negotiations, and the agreements reached, will determine how effective the resolution will be.
The most significant factor which predicts how difficult or easy interjurisdictional relationships will be is regional political support for transit. Strong regional commitment to transit has significantly smoothed the process for agreements and productive planning. European and Canadian experience has shown that transit decision-making works best if all parties are located under one political entity. These entities are generally city government. This political structure is similar to what is currently in place in San Francisco.
King County transit in Seattle has recognized the need for consensus among the various jurisdictions involved in the transit operations as well as among the region’s traffic engineers and transit professionals (27). Mandates and strategies of all of the participating agencies must be accommodated. It becomes absolutely essential that all parties are involved in the process and a working relationship established at the signal priority project’s initial inception.
Financial Considerations
Regional political commitment to transit is not all that is necessary. Funding is also a key concern in cementing institutional relationships as well as ultimately implementing a signal priority system for transit operations. Even if new standards are created for traffic signals, signage, priority methods, and levels of priority, without identified funding sources, political support is difficult to achieve. If funds were more available, cities and transit authorities would be more likely to consider the benefits of signal priority systems. The cost of a signal priority system for transit operations can range between $10,000 and $30,000 per signalized intersection depending on the adaptability of the existing traffic signal equipment and the priority method selected (24-25, 28-29). Financial considerations and the source of the funding necessary to support a signal priority system is the first, and in some cases the foremost, barrier that prevents the implementation of a transit priority system.
A substantial amount of funding for transit operations and maintenance comes from the Federal Transit Agency (FTA). Many transit agencies could not continue to operate without this funding source. It is FTA funds that are also commonly relied upon for capital improvements such as the implementation of a signal priority system. It is not so much that these funds are used directly for the priority system, but they provide the operating basis necessary while general revenue funds are used for operational improvements. A considerable barrier being faced today by transit agencies who are considering implementing or adding to the current transit priority system is a substantial decrease in this funding source. Table 6 provides an overview of the changes in FTA funding in fiscal year (FY) 1996. As observed, the current FY 1996 transit appropriations will reduce transit funds provided to transit agencies and cities by up to 30 percent (30). This decrease in funding will
F-20 require almost all transit agencies to increase fares to replace the lost revenue and cause the elimination or substantial delay of improvement projects such as signal priority systems. Many transit agencies who desire a signal priority system for transit operations will simply not be able to afford the implementation.
Liability
Liability associated with any new technology that becomes part of the traffic management system, such as signal priority systems for transit, is of concern to transportation officials and creates a potential barrier to implementation. Most of the liability concerns expressed encompass operational issues related to the failure of the system to call the appropriate priority phase and signal or pedestrian indication as the transit vehicles approach the intersection. However, the liability associated with signal priority is no different from any traffic signal location. There is longstanding case law support for the premise that the operator of a vehicle cannot blindly rely upon signals at intersections without a reasonable lookout to avoid an accident (31). For example, in Nolan v. Sullivan, the court stated that a green light is not a command to go; it is a qualified permission. Although no case law was found specifically tied to signal priority systems, no liability beyond that experienced with traffic signal operations should be expected. None of the transit agencies reported liability to be a barrier to implementation but only as a concern in the development and operation of the priority system.
Table 6. FTA Funding Comparison (30).
Location FY 1995 FY 1996 Dollar Fare Increase Funding from Funding from Reduction to Replace FTA (millions) FTA (millions) ( millions) Funds (%) Nationwide** $710 $400 $310 44 New York State $866 $824 $42 9 New York City** $117 $61 $56 3 Texas $190 $164 $26 14 32 Metro Areas of 1 ------9 Million Population 500,000 to 1 Million ------14 Population Areas Less than 500,000 ------44-73 Population Areas ** Operating Assistance Funds Only
F-21 Public Support
Although public support is critical to the initial implementation of a public transit system, most agencies suggest that the initial implementation of a signal priority system requires little public support. However, proponents of signal priority hope that public support of the efficiencies gained with transit priority will lead to public demand for a widespread application of this technology. Most agencies will use the media to describe and promote the signal priority system for transit operations and present the associated benefits to the public. Transit agencies will also develop promotional brochures and use displays at public events, shopping malls and county fairs (32). It is important to convenience the public that transit deserves priority over general purpose traffic at locations where signal priority is used (29).
Project Champion
The importance of a project champion when implementing any new initiative cannot be overstated. Often, the project champion is the management of the transit and city transportation operating agencies. In other cases, it is a politician with influence related to the initiation and funding of the program. Kitsap transit was effective is using the political process to spearhead the initiation of the signal priority system that is currently in place (32). This leadership can also be provided through adoption of transportation policy and philosophy that encompasses the entire organization. For example, the City of Edmonton, Alberta officially adopted a transportation philosophy which emphasized improvements in the efficiency of the existing roadway network as an alternative to providing new facilities (33). This transportation philosophy along with improvements to transit services were designed to accommodate a greater share of the transportation demand during peak hours. The benefits obtained for transit signal priority systems are consistent with these philosophies and allow for “champion” support of these initiatives.
Operational Considerations
Many components of transit operational and geometric design are important factors in the implementation of signal priority systems for transit. These important factors can become significant barriers to implementation if the demonstrated criteria are not satisfied.
Cross-Street and Intersection Volumes
Cross-street traffic volumes at intersections under signal priority control for transit vehicles are an important consideration. The problems associated with delay and queue development on the non-priority movements at each intersection may outweigh the benefits received from transit signal priority. ITE technical committee 6A-42 determined that cross-street volumes less than 20,000 ADT allow feasible LRT operation with as much as three to four car LRT trains and three to six minute headways (34). The City of Portland has successfully implemented priority and preemption strategies with cross-street traffic as high as 24,500 ADT (35). Heavy left-turn or right-turn volumes over LRT facilities may require special design treatments.
F-22 Level of Congestion
Increased levels of congestion lead to high V/C ratios at intersections. The two main problems associated with congestion include the little spare green time available to reallocate to transit and travel time predictions for upstream detections become less reliable leading to inappropriate signal decisions and phase changes. Extreme levels of congestion during peak hour travel times do not allow for the use of signal priority systems for transit due to the inability of the priority methods to complete their desired functions.
Transit delay savings reduce substantially when congestion occurs. In London, delay savings averaging 10 seconds/bus/intersection with signal priority and V/C ratios of 0.5 to 0.7 were reduced to 3 seconds/bus/intersection with V/C ratios greater than 0.85. The best situation for signal priority for transit vehicles is intersections operating at a relatively low peak-hour V/C of 0.5 (36). Low V/C ratios combined with transit headways of 10 to 15 minutes has had a significant influence on the success reported by cities with signal priority systems for transit such as Bremerton, WA (37).
Stone and Wild look at the effects of V/C ratios on the transit route in relation to the cross- street volumes and transit headways (38). The results are shown in Figure 6. Note that any V/C ratio over 0.85 on the transit route is considered unacceptable for transit signal priority and may not be appropriate for at-grade transit at all.
1.1
Unacceptable 1 V/C area
0.9
0.8
0.7 V/C Ratio on Transit Route
0.6 10,000 20,000 30,000 40,000 Cross-Street Daily Volume Transit Headways
No LRT 20 Minutes 10 Minutes 6 Minutes 2 Minutes
Figure 6. Transit Route V/C Ratio versus Cross-Street Volume for a Range of LRT Headways (With Preemption)(26).
F-23 Delay
Figure 7 shows the net savings of delay due to preemption versus cross-street traffic volumes (38). When comparing the results presented in Figure 6 to that of Figure 7, some differences are evident. First, the delay criterion gives results that are more consistent with the common objective of maximizing the overall person-carrying capacity of the intersection. Thus, as the frequency of LRT service increases, the savings in overall person-delay also increases. The justification for priority treatment for LRT generally increases as the line volume increases, until the headways are so short and cross-street volumes are so high that they greatly begin to increase vehicle delay. It was also found that preemption can be justified for all but two of the combinations of LRT headways and cross-street volumes, whereas the V/C ratio criterion resulted in many more design situations falling above the 0.85 maximum level. Delay to both transit and non-transit vehicles can be further reduced by integrating signal coordination into the system and reducing the number of conflicts between vehicle types (39).
40 LRT Headways 30
20 Minutes 20 10 Minutes
10 6 Minutes
2 Minutes
Person-Hours of Delay Saved 0
-10 10,000 20,000 30,000 40,000 Cross Street Volume
Figure 7. Net Person-Hours of Delay Avoided by Preemption During the Peak Hour (38).
F-24 Traffic Signal Operations
Traffic signal operations are the cornerstones to effective priority treatments. One consistently reported problem in the implementation of signal priority systems is the philosophy of a two-control system, one for traffic signal operations, and one for the transit system. Obviously, these systems cannot be independent of each other since both of them are ultimately part of the entire area wide transportation system. One of the successes of the agencies who currently have signal priority for transit in place is the integration of both control systems throughout the transit routes.
Figure 8 depicts a typical flow chart describing the controller logic sequence under transit signal priority (40). Depending on the type of priority in place, the detection of a transit vehicle requesting priority initiates a series of steps that brings on the appropriate priority phase, holds the phase until either canceled by the transit vehicle or by an expired maximum time constraint, terminates the phase, and returns to the normal signal cycle. As additional constraints are added, the flow chart becomes increasingly detailed. A flow chart depicting the signal priority control logic for Queens Street in Toronto included 41 separate steps (28).
Figure 8. An Overview of Controller Logic for Transit Signal Priority (40).
F-25 The location of the transit facilities within the street corridor affects the type of transit priority treatment that is feasible and may provide a barrier to implementation. When the transit facilities are located in the median of an arterial, it may be required that all movements crossing the tracks be protected by a separate phase (18). This may require up to 12 phases at a signalized intersection. Existing traffic controllers must have the capability to handle these additional phases or allow for expansion of the internal controller hardware. The traffic signal controller must also be capable of allowing additional clearance time on the transit phase. The development of traffic queues and large pedestrian volumes at the intersection, especially during peak-hour periods, alters the speed, acceleration, and deceleration capabilities of the transit vehicle. Because of this, clearance intervals of up to 10 seconds may be required (as compared to the typical 4 to 5 seconds) for transit operations (36).
These additional phases must be supported by the appropriate signal displays for all movements. The space for placement of these additional traffic control signals must be available. Placing the transit signals in locations that will not be confusing to motorists is important. It is also important that signals for transit be designed with symbols or words providing a clear distinction between transit and vehicle control. Figure 9 provides examples of the traffic signal indications used for transit operations.
The software used to support many LRT signal operations provide warning to the LRT operator, through signal indications, before the preemption signal can change (41). The preemption signal normally rests with the horizontal bar lit, which is the LRT stop indication. If the preemption is proceeding normally, the horizontal bar will flash for five seconds before changing. The five seconds of flash time give the LRT operator additional warning and widens the decision window to approximately seven seconds in advance of the decision point marker. Similarly, the preemption phase cannot revert to the stop phase without flashing for five seconds. Thus, if the preemption should accidentally terminate due to a false check-out or other unknown reason, there is no condition in which the LRT could enter the intersection against the signal once it has passed the decision point marker. One of the benefits of this system is if the LRT is exceeding the design speed of the rail location, the preemption will not occur by the time the LRT vehicle reaches the decision point marker requiring the LRT operator to slow the vehicle to an appropriate speed and proceed when the preemption occurs. This protocol provides additional safety measures to the overall operation.
Transit Operator Control
The effect of transit operator control on the operation of a signal priority system for transit is not commonly considered a barrier to implementation. There is very little that the transit operator can to do abuse or affect the signal priority system. Certain priority systems allow the transit operator to signal for priority manually. Here, transit operators are instructed to only signal for priority when they are traversing a primary route or when they are behind schedule. The primary concern with LRT vehicle operators is their expectation that priority will be available at selected intersections eliminating the necessity to stop. Most transit agencies overcome this concern by training the transit operators to follow the signal control procedures. Further, any violation of a red signal to the LRT vehicle as it is approaching an intersection can trigger an automatic breaking system which brings the LRT vehicle to a complete stop prior to the intersection.
F-26 Figure 9. Example of LRT Signal Displays (39).
F-27 During the design of a transit preemption system, the City of Portland had extensive debate about whether the train operator should receive indication that the transit vehicle has been detected for preemption (41). The City of Portland decided not to provide this information to the transit operator since the point of detection was approximately 1200 feet from the intersection and did not in itself guarantee preemption. Portland also determined that the transit operator does not need to know if the transit vehicle is detected, but only whether proceeding is safe. This information is provided only by the transit and traffic signal indications.
Signal Priority Methods
Many different types of signal priority methods were presented in a previous section of this report. The signal priority methods in themselves do not provide a barrier to implementation. However, the selection of the appropriate signal priority method is the key to providing the most effective and efficient operation at the intersection.
The ability to provide different levels of signal priority control throughout the day may provide for additional efficiencies within the system. Custom designed software packages within the controller can enable all intersections or selected intersections to provide either full, partial, or no priority at various times. The selection of the form of priority can be made in one of the following manners (42):
1. Time of day - The degree of priority can vary by time of day. Almost no priority can be provided during peak periods whereas full or partial priority may be provided at other times.
2. Vehicle responsive - Vehicle detection can be the sole method of signal priority initiation. Vehicle detection devices can be installed such that the level of priority can be reduced or deactivated once excess queues are detected. They can also be deactivated during peak periods or during incidents.
3. Manual - The level of priority can be controlled from a central control center and changed as appropriate to meet current conditions.
Hardware/Software Constraints
Current technology and recent advances in both hardware and software development have minimized the potential constraints related to the implementation of signal priority systems. Most controllers and computer operational environments are easily adapted to the introduction of the software necessary to implement signal priority for transit operations. The City of Portland found that existing traffic signal hardware and control techniques can be adapted for LRT priority interfaces through the addition of the appropriate hardware and software in a cost-effective manner (41). The city of Los Angeles experienced logic problems between ATSAC and the priority algorithms that were in place for bus transit priority (29). This provided only a temporary barrier as the software was reconfigured and the bus transit priority reestablished.
F-28 Transit Density
The density of transit vehicles, especially during the peak hour, has a significant effect on the viability of signal priority systems. Priority systems for bus densities greater than 60 buses/hour have been found to be less effective. With bus densities of 60 or more per hour, there is essentially a constant call for priority. This has the potential to cause extreme delays and large queues to non- priority movements. With bus densities at this level, signal offset coordination for transit may be more appropriate.
At least 10 or 15 buses carrying 400 to 600 passengers would normally be required to warrant bus preemption (36). This is in contrast to LRT where only 2 trains per hour may warrant priority or preemption schemes. LRT headways under 10 minutes or with extremely variable headways may create operational problems. However, Berry and Williams found that the arrival of LRT vehicles at crossing was a predictable event and that transit headways were generally maintained (43).
Whenever a signal is preempted, progression will be disturbed on the affected streets. Where collector streets intersect an arterial with LRT operations, this disturbance will likely be minor. Where the LRT crosses a multi-lane arterial on which signal progression is a major factor in the traffic level-of-service, an evaluation of total person delay must be completed. This is even more significant when another transit route is located on the cross-street. Overlapping the LRT phase with extension or recall of a compatible traffic movement may be more effective than to have full transit preemption.
Intersection Spacing and Transit Stop Locations
The necessary intersection spacing for effective signal priority systems is determined by the dwell and loading effects of the transit vehicle. If the preempted signals are to close to the normal meeting or passing points for LRT in opposite directions, then the signal may be preempted by a second LRT before traffic queues have had a chance to clear. This creates the potential for serious and cumulative delays to other traffic. Because of this, the ideal intersection spacing along the LRT transit line should be at least 1600 feet. This criterion applies to both preempted, priority and non- priority intersections. Although 1600 feet is a desirable intersection spacing, it is unlikely that this will be attainable in most locations. For example, the downtown Los Angeles segment of the LRT system has intersection spacings ranging from as low as 270 feet to 1200 feet and Long Beach has intersection spacings ranging from 440 to 1625 feet (14). The LRT system is still able to provide appropriate priority signal control at these narrow spacings. Variable intersection spacings, however, may cause additional problems.
Preemption of traffic signal for LRT transit will generally best fit with farside stops averaging under 3 boardings per door channel in the peak periods (36). If transit stops are a function of heavy boarding, many of the advantages of the signal preemption will be negated by boarding delay. LRT vehicles generally load faster than a bus with individual fare collection. Loading during the red phase at a nearside stop will most likely benefit buses more than LRT. Farside stops, which lend themselves to signal priority, will minimize delay to LRT. In general, the following principles should be considered when locating transit stops to minimize signal delay to transit vehicles:
F-29 1. If transit vehicles tend to arrive at a traffic signal during the green phase, the boarding stop should be located on the farside of the intersection. This allows the transit vehicle to take advantage of the green signal.
2. If transit vehicles tend to arrive at a traffic signal during the red phase, the transit stop should be located on the nearside of the intersection, since the transit vehicle must stop at the red signal anyway. The transit vehicle can then dwell at this location until the next green phase.
3. Opportunities for transit vehicles to pass through two or more consecutive green traffic signals can be maximized if transit stops and traffic signal timing are considered together.
It is often felt by transit operators that adding additional boarding stops along the transit route provide more convenience and benefit to the public who wish to use transit. Actually, this may not be the case. The strategic location of boarding stops and the removal of excess transit stops will increase the distance between stops and reduce the time lost in accelerating, decelerating, and weaving. Increases in average travel speed of the transit vehicle will be experienced reducing the overall transit travel time. Less transit stops may make transit more attractive.
Basic Geometry
Basic roadway geometry may not be a factor or barrier in the implementation of signal priority systems within existing transit routes. It is assumed that the necessary transit system geometrics are already in place and functioning properly. Maximum queue development during the transit priority phase should be computed to assure that ample storage space exists and no significant problems with queue spillback will develop. The geometry of the transit corridor must be conducive to the additional traffic control requirements for priority signal control. Table 7 presents some basic LRT vehicle characteristics that determine the necessary geometric and clearance time requirements (18, 44).
System Operation
Detection location is an important factor in priority control and in the operation of signal priority systems. For efficient priority, LRT and buses should be detected far enough upstream of an intersection to allow for the signal to adjust gradually to the transit vehicle arrival without disrupting the quality of signal control for the general traffic. The necessary upstream detection location will depend on transit speed as well as congestion/delays, upstream boarding stops, driveway activity, and transit performance characteristics. The detection location will also depend on the detection method employed. This detector should be placed far enough from the intersection to prevent vehicle queues from overtaking the loop and close enough to minimize travel time variability. In areas of tight intersection spacing on the transit route, a lack of necessary length upstream of the intersection may not allow the effective implementation of a priority system. The range of detection locations identified in this investigation is shown in Table 8.
F-30 Table 7. LRT Vehicle Characteristics.
Characteristic Value Acceleration 2 mph/second Deceleration 3 to 3.5 mph/second Maximum Braking Rate 4 mph/second Emergency Braking Rate 6 mph/second Number of Articulations 0, 1, or 2 Length 60 - 90 feet per vehicle Weight 100,000 lbs. (Empty) Width 7.9 - 9.3 feet Turning Radius 42 - 82 feet
Table 8. Typical Detector Locations for Transit Priority.
Upstream Detection Upstream Detection Intersection Detection Method Location (feet) Location (sec) Detection (feet) Inductance Loop 200-1200 30-50 (desirable) 0-70 Infrared Light 200-1000 max. available 0 Ultrasonic Sound up to 2600* max. available 0 AVI Variable max. available 0 *Includes Emergency Vehicle Detection
F-31 In many cases, inductance loop detection methods will be used with each transit vehicle approach having two detectors. The first detector is located just past the upstream intersection or at a location within a predetermined travel distance to the intersection. As the transit vehicle passes through the upstream intersection and actuates the detection, the signal priority sequence is initiated. This includes the detection of the transit vehicle, the initiation of the priority sequences and the altering of the linking offsets at the coordinated signals to improve progression along the roadway (assuming coordination is in place). The second detector, the stop line/release detector, is located at or near the intersection. This detector serves two functions. First, if the controller is displaying a “go” signal for the LRT vehicle, actuation will start the light rail clearance intervals, release the priority function, and dissipate the queues that may impede the transit vehicles at the intersection. If an advance detection is not received or if the transit vehicle arrival at the intersection is delayed, actuation of the detector will place a non-priority call to the LRT phase and cancel the call for priority from the previous loop.
The City of Portland uses loop detectors for initiating transit priority at a number of intersections. An additional transit detector may be placed as far upstream as practical, known at the “pedestrian inhibitor,” which begins the phasing changes in the controller to prepare for transit priority (35). This phasing change begins by initiating a pedestrian clearance interval for all pedestrian movements at the intersection when activated by transit. If “walk” is active on any of the conflicting movements, the controller will immediately go to flashing “don’t walk” for the programmed pedestrian clearance time. The pedestrian inhibit feature will not allow any pedestrian phases to begin until a preempt occurs or until a maximum priority time, based on transit speed, is reached (45). Actual preempt call detectors are located approximately halfway between the inhibitor detector and the intersection. The preempt call does not override the timing of flashing “don’t walk” or the yellow intervals. A preempt is terminated when the transit vehicle passes over a “check-out” detector or when a timer times out. If the preempt fails, the transit operators are instructed to stop at the intersection and then proceed cautiously through the intersection when the parallel vehicular signal is green. The marked “decision point” along the LRT alignment indicates a point that the transit operator must begin braking if preemption is not received.
No single location for the upstream loop detector will be optimum for all scenarios and all periods of the day. Thus, it is suggested that the loop detector be placed as far as feasible from the intersection. This will prevent any potential for traffic queuing at the intersection to queue back over the detectors and not allow the transit vehicle to activate the detector. A technique used in Australia to overcome the problem with locating the upstream loop is “image position”(46). Image position is programmed into the controller at the intersection with the constraint that the delays to transit between the advanced detector loop and stop line would be caused only by excessive traffic queuing at the intersection. When the upstream detector loop is activated using the image position feature, a delay timer in the signal controller delays the transit call for the priority phase. The delay setting in the delay timer automatically changes by time of day so that the image position of the loop is close to the intersection during periods of short traffic queues and further away during periods of longer traffic queues. The change timer is accessible from any central control unit thus the “image position” could be altered manually as the circumstances necessitate.
F-32 Many locations including Santa Clara County and the City of Los Angeles, like the City of Portland and the City of Melbourne, Australia, use inductance loop detectors for LRT vehicle detection (14, 18, 46). Generally, transit activates only the stopline loop if they are at the head of the traffic queue and no longer require the priority phase. Another detector can be placed approximately 20 feet beyond the intersection to repeat the series for the next downstream intersection. In the instances where there is an LRT station between the upstream and target intersections, the advanced detector is placed so that it is actuated as soon as the LRT vehicle leaves the station. When the station is less than 200 feet from the target intersection, no advanced detection is used. The release of the LRT vehicle is then coordinated with the signal phasing. An example of a typical layout for a median LRT operation is shown in Figure 10 (41).
As discussed in previous sections of this report, there are a number of other technologies used for detection of transit vehicles under an emitter/detector method. The emitter, located on the transit vehicle, sends either a light (infrared), sound (ultrasonic) or radio frequency signal. Given a predetermined level of intensity, the signal is detected by a detection device usually located at the intersection. Inductance loops may also serve as emitter detection devices. After receiving the signal, the detection device then sends a message to the controller requesting priority. The distance from the intersection that the emitted frequency is first detected is variable and often based on the effects of weather and blockage by fixed objects. However, as with loop detectors, the detection is calculated to take place at a distance from the intersection that allows for the most effective change to the priority phase sequence. Table 4, located in a previous section of this report, provides a detailed overview of the infrared and ultrasonic emitter/detector systems.
The City of Toronto uses a unique method of transit vehicle detection for its streetcar transit system. On Queens Street in Toronto, the streetcars are equipped with a transponder that emits a constant single frequency radio signal (28). This radio signal, designed to provide track switching, is also used for transit detection for signal priority. A series of loop detectors have been placed in the street pavement. As the transit vehicle passes over the loop detector, the radio frequency signal is detected and a signal preemption request is initiated. Two loops, a call for priority loop upstream and a cancel priority loop at the intersection, are used. A combination of central and local traffic signal controllers extend the transit phase green time while maintaining the offset timing and signal cycle times along the roadway. Figure 11 provides a depiction of this method.
F-33 Figure 10. Typical Traffic Signal Layout for Median LRT Operation (41).
F-34 Figure 11. Queen Street Signal Preemption Process (46).
F-35 Traffic System Operators
Most traffic engineers assigned to the task of operating and maintaining a traffic control system spend much of their time looking at ways to optimize the efficiency of the system. This is generally completed by analyzing ways to reduce vehicle delay and improve the level-of-service at each signalized intersection. Signal priority systems for transit will reduce the total person delay but may add small amounts of vehicle delay to the non-priority movements. This would seem counterproductive to the traffic engineer who may not accept changes that add delay to the overall traffic system. Failure to demonstrate the benefits of signal priority and establishing the support of the traffic engineering staff can provide a significant barrier to the implementation of a signal priority system for transit. Adding a traffic engineer to the staff of the transit agency may be one way to address this potential barrier. This will allow much of the traffic engineering analysis associated with the signal priority system to be completed in-house and also provide a member of the transit agency staff who “speaks the language” of the city traffic engineers.
Human Factors
Driver capabilities and limitations must be considered to ensure a successful implementation of a signal priority system for transit. The implementation of traffic signal priority for transit can add variability to the traffic control operations. When priority treatments are implemented, each signal cycle in which signal priority is initiated is likely to be different from the previous cycle. Variable signal cycles can lead to violations of both ad hoc and a priori expectancies of drivers. This can also affect pedestrian operations in areas of high pedestrian traffic. One primary result of violations in human factors issues are public complaints (32). Public officials, most often the city traffic engineering staff, required to handle these complaints can turn from friend to foe quickly and ultimately become a barrier to new implementations of signal priority systems for transit.
Allowable Minimum Green Phases
The use of signal priority systems for transit operations does not affect minimum green times during any phase. When a request for priority is received by the controller, even under full preemption, no changes are made to accommodate this request until the minimum green times are satisfied.
Pedestrian Constraints
As with minimum green times, minimum flashing “don't walk” times are also guaranteed under all priority treatments. No change in signal phasing to satisfy the request for priority will be made until the minimum time for pedestrian clearance in conflicting phases has been satisfied. At locations where pedestrians cross the LRT outside the control of a signalized intersection, a “Z” crossing is used which is simply a sidewalk that runs parallel to the LRT tracks on both sides before crossing the tracks. This requires that pedestrians face the direction of the LRT to assure that they look for the presence of an LRT vehicle prior to crossing. This crossing method has been designed to maximize the safety of pedestrians. A typical “Z” crossing configuration is shown in Figure 12 (41).
F-36 Figure 12. Pedestrian “Z” Crossing (41).
Driver Expectancy
Due to limitations in acceleration and deceleration and increased congestion during the peak hour, LRT will require a minimum clearance interval of 10 seconds rather than the typical 4 or 5 seconds (36). This change in clearance time leads to a violation of driver expectancy. The variability of the signal cycle also leads to expectancy violations. LRT is seldom part of the general traffic flow; thus, any encounter with non-transit traffic may be an unexpected event. Violations of driver expectancy can be minimized by initiating the transit priority methods as early in the signal cycle as possible. This will allow for a timely transfer of signal phases back to the transit phase. Since bus transit operations are most often part of the general traffic stream, bus transit should have little impact on driver expectancy.
Safety and Fail Conditions
Signal priority systems for transit can facilitate and enhance safety for transit operations by minimizing potential vehicle conflicts (39). Safety is further enhanced when signal priority is integrated with signal coordination on the transit route. The primary safety concern associated with signal priority for transit is the failure mode when the priority system does not operate properly. Essentially, if the priority system fails to operate as intended, it must not create unsafe conditions nor should it require the transit operator to make an emergency stop. Each of these lead to the desirable "fail safe" outcome. Transit operators are trained to identify unsafe situations and only proceed when conditions are appropriate.
F-37 Enforcement
The enforcement of a signal priority system for transit operations relates to the protection of the integrity of the priority system. Policies and procedures within each transit agency protect the quality of the system. No problems with enforcement of a priority system were reported by any of the transit agencies interviewed. Many of the potential enforcement problems are controlled by constraints within the priority system control algorithms within the traffic signal controller.
Compatibility
Compatibility of the system is concerned with the ability of the signal priority system to be transferred and applied between adjacent communities and transit operations. When considering a region-wide system, there is no need to maintain consistency in the selection of the signal control strategy. Adjacent agencies and even adjacent traffic signals can make decisions on signal control using totally different logic. The method of detection and/or AVI system, however, must be the same across all agencies to minimize the cost and impracticality of outfitting transit vehicles with more than one technology.
Barriers to Implementation Matrix
The matrix presented in Table 9 describes the principle barriers to implementation identified in this analysis. Barriers identified have been derived by the author through knowledge obtained primarily from the interview process and supported as necessary from the literature. Understanding of these barriers to implementation of signal priority systems for transit will help transit agencies as they begin the development process.
F-38 Table 9. Primary Barriers to Implementation of Signal Priority Systems.
Type Barrier Barrier to Implementation
Institutional/ Financing All new projects require the appropriate financial support to implement the Agency system sufficiently. Signal priority systems for transit operations are impossible without the necessary funds. The FTA continues to reduce the amount of funding provided to transit agencies.
Agency Signal priority systems cannot be implemented without the support of all the Cooperation agencies involved. This commonly requires a champion within one of the lead and Top organizations to develop and maintain support for the priority system. Signal Management priority systems for transit is not attainable without management support. This Support requires the adoption of a policy to maximize the movement of people, not vehicles. Responsibility for operations and maintenance must also be determined at the beginning of the project.
Liability The idea of "randomly" altering the traffic signal systems based on transit Related to priority needs obtains the attention of many city attorneys. If the proponents Priority of the signal priority system cannot demonstrate the safety and features of the System Failure system that allow "fail safe" operations, the priority system will be a hard sell. There is no additional exposure beyond standard traffic signal applications. Tort liability is managed through legislation and indemnification.
Operational Arterial and The signal priority system for transit operations will not be effective with high Cross-Street cross-street traffic and large V/C, congestion, and delay levels during peak Volumes periods but may be effective during off-peak periods. Signal progression or transit routes on the cross-street must not be a major concern.
Signal Priority The signal priority methods proposed must be flexible and meet the viable Methods needs of transit and traffic operations throughout the day.
Transit Large transit volumes during peak periods makes signal priority infeasible. Vehicle Transit volumes ultimately reach a saturation point where a continuous request Density for priority is at the signal controller. This can have a detrimental effect on cross-street traffic operations and produce delay costs that exceed the benefits obtained.
Traffic System One of the largest barriers in implementing a signal priority system may be the Operators traffic operations engineers. Anything that alters the progression or efficiency of the traffic system design will be looked upon as an unfavorable solution for transit improvement. Failure of the traffic engineer to support the project may stop the project. The transit agency must be willing to work with the traffic engineer and demonstrate the benefits and total person delay savings.
Human Driver The variability in phasing experienced by drivers should not provide a safety Factors Expectancy risk. Fail safe conditions should be built into all priority schemes. Public support can be a major lift in further development of the priority system.
Pedestrians Safety to pedestrians during the priority treatment will be a major concern to all involved. Signal priority is not effective in areas where large pedestrian volumes exist.
F-39 EVALUATING NEW/PROPOSED TRANSIT PRIORITY SYSTEMS
A number of evaluation steps should be completed prior to beginning the process of implementing a traffic signal priority system for transit. The evaluation of performance measures, benefits and cost will allow the transit agency to develop a full understanding of the priority system and prepare for overcoming some of the barriers to implementation that will be faced.
Some basic performance measures and site considerations that should be evaluated include (19, 33, 27):
1. Degree of saturation; 2. Transit delay on transit route; 3. Person delay; 4. Transit services on cross-street; 5. Fuel emissions and consumption; 6. Stops Locations (Nearside, Middle, Farside); 7. On-time performance; 8. Signal timing flexibility; 9. Adjacent signals on all approaches to the intersection; 10. Similar cycle lengths on adjacent signals; 11. Signal coordination on transit and/or side-street; 12. Representative and similar geometry on all approaches; 13. Queue storage space; 14. LRT/bus vehicle speed and headways; 15. LRT station locations; 16. Bus stop locations; 17. LRT/bus vehicle characteristics; 18. Controller currently equipped with communication equipment; 19. Controller compatibility with current signal priority technologies.
Benefits to consider include:
1. Transit passenger travel time savings; 2. Transit passenger waiting time savings; 3. Transit passenger predictability savings; 4. Transit passenger capacity increases; 5. Transit operator cost savings in operating costs and reduced number of vehicles; 6. Environmental benefits; 7. Pedestrian benefits; 8. Benefits from generated transit trips; 9. Maximizing safety; 10. Maximizing public confidence in the system.
F-40 Costs to consider:
1. Non-transit vehicle time losses and delay costs; 2. Transit vehicle delay on cross-streets; 3. Degenerated non-transit vehicle trips; 4. Environmental costs; 5. Pedestrian costs; 6. Capital costs including equipment, signs, markings, and infrastructure costs; 7. Maintenance of priority equipment; 8. Enforcement costs.
Fully addressing each of these factors will provide an understanding of the effectiveness of the proposed priority system.
Simulation of Proposed Systems
One of the most significant advancements in recent years in the evaluation of the potential benefits of signal priority systems for transit has been the development of simulation software. Before this time, the only feasible way to evaluate the potential benefits of a signal priority system for transit was to implement a small system and evaluate the before and after conditions. Simulation has a number of significant advantages (23). A means of addressing particularly complex analytical problems, which may not be susceptible to direct analytical treatment, is provided through simulation. The analyst is permitted to focus on specific portions of the transit system using simulation and experimentation with new ideas which have yet to be put into practice. Simulation avoids the very real risk of failure implicit in any extensive program of transit operations experimentation and is generally considerably quicker, more flexible, and less expensive than other forms of complex, analytical evaluation. Foremost, simulation provides a way to evaluate operational barriers and demonstrate the benefits of signal priority for transit prior to implementation.
A number of simulation software packages have been developed and tested. TRGMSM is an object-oriented microscopic simulation model allowing visual display of intersection traffic operations including a range of transit functions (47). The model is structured to allow the simulation of any specified signal control system and signal priority strategy. Total person delay (based on 1.5 persons/vehicle and 80 persons/LRT vehicle) and average vehicle delay are used as the primary assessment factors for the simulation results.
PREEMPT is a software package developed at Wayne State University that can estimate transit driving times based on varying speeds and can calculate required fleet sizes, operating costs, revenue, and demand based on predetermined values (20). Input requirements include transit demand and market capture values, transit vehicle characteristics, transit capacity, and number of stops. The PREEMPT software has been used to simulate transit sectors in the Detroit area. The results indicate that signal preemption for transit can reduce operating costs while increasing ridership demand.
F-41 PTV Vision is a planning and traffic management software package developed in Germany (48). PTV Vision will simulate the interaction between actuated control facilities and priority-based transit operations. This software also takes into account the location of transit stops, transit routes, and transit detectors in terms of both the function and geometric location of their operation.
TransSim II is a simulation program that models light rail transit or bus transit operations (1). TransSim II is a link-node based model that treats transit operations on a microscopic level and other traffic on a macroscopic level. The utility of the model lies in the abundance of information that is modeled on transit and traffic signal operation. Transit operations are modeled on a real-time basis through a traffic signal controlled street network. All common types of traffic controllers can be modeled and are simulated on a second-by-second basis. The simulation can be set to many of the most common types of priority schemes including full preemption. Inputs to the program include features of the roadway environment, including geometrics, traffic volumes, signal phasing, and information about transit routes including stations and intersections. TransSim II provides a number of measures of effectiveness (MOEs) as outputs including average speeds, dwell times and delays to the transit vehicles. This simulation method has been applied in Chicago to allow a design team to successfully identify the most appropriate priority strategy for a proposed light rail transit system, before construction (1). TransSim II also allowed Chicago to explore a number of different priority schemes and their associated impacts. The model was also found to be advantageous in providing a user friendly environment for modeling the LRT environment and the explicit modeling of controller behavior and LRT priority algorithms (49).
F-42 CHARACTERISTICS/GUIDELINES FOR IMPLEMENTATION
Many factors and issues must be evaluated when a transit agency is considering the implementation of a signal priority system. Two important questions must be answered:
1. What characteristics are in place for determining if transit priority systems are worthwhile? 2. What guidelines criteria must be satisfied to implement a priority system?
This section presents a comprehensive list of characteristics and guidelines in an attempt to answer the above questions. The characteristics and guidelines were developed by the author based on information obtained in the interview and literature review processes. Unique combinations of the transit, traffic, signal, and agency characteristics provide the primary factors that in turn develop the characteristics and guidelines for implementation. The factors to consider include:
Transit Organization C Transit Agency C City Traffic Engineer C Metropolitan Planning Organization (MPO)
Transit Type C Bus C LRT
Transit Network Characteristics C Shared/exclusive lanes C Cross-street volumes/transit routes C CBD routes
Level and Type of Transit Service C High ridership routes C High volume routes C Fixed-route service C Transit schedules C Transit headways
Stop/Station Characteristics C Nearside/farside transit stops C Median/curb transit location C Cross-street intersection spacing
Traffic Characteristics C Intersection level-of-service C Approach street level-of-service C Cross-street volumes C Queuing
F-43 Signal Control System C Coordinated/isolated operation C Fixed/actuated signal control C Cycle length C Available green time
Transit Identification System C Presence of AVI system C Technology selection
Each factor described above lead to specific characteristics and guidelines than should be evaluated when considering a signal priority system. The following sections provide detailed characteristics and guidelines.
Transit Organization
Characteristics: The transit organization identified for the signal priority project must be brought together early in the process. Funding sources should be identified. Relationships should be established and formal agreements reached concerning the design, operation, and maintenance of the priority system between the management of each agency. A protocol should also be developed for changes made to the system. Involving the political process may provide assistance in this interagency development. The emergence of an influential project champion will expedite the development process.
Employing a traffic engineer within the transit agency, either as a consultant or permanent employee, will allow more effective dialog between the transit agency and city traffic engineers. Methods of developing the signal priority system for transit can be completed with the city traffic engineering staff through a series of working meetings.
The transit agency should publicize the signal priority system after completion of the initial phase to win public support for continued development throughout the transit region. A public education campaign should also be conducted in an attempt to increase transit ridership under the new, more efficient, mode of transportation.
Guidelines: 1. The installation of signal priority systems for transit operations can range from $10,000 to $30,000 per intersection depending on the priority method selected. 2. Include promotional costs in project budget.
F-44 Transit Type
Characteristics: Signal priority is applicable to both LRT and bus operation. However, signal controller algorithms are not always applicable to both types of operation. Clearance times are generally shorter for bus operations and buses are able to move in and out of the traffic flow. LRT is typically provided separate signal indicators/indications and phases not normally provided for buses. Buses may use unique priority methods, such as queue jumping, which reduce the potential effect to the non-transit phases. Transit vehicle detection technology designed to activate a call for priority should be the same for all transit types within the transit agency and the transit region.
Guidelines: 1. Existing signal controllers must be able to accommodate priority algorithms and additional phases. 2. Controller logic should be able to allow variable timing parameters. 3. Transit vehicle detection technology must be compatible with controller algorithms. 4. Transit vehicles should be equipped with the same vehicle detection equipment that does not contain jurisdictional boundaries.
Transit Network Characteristics
Characteristics: Transit vehicle operating in shared lanes can become constricted by other traffic. Both bus and LRT transit vehicles can become trapped behind the vehicle queue, without a mechanism to "queue jump," adding delay to the transit vehicle. Shared lanes also add variability to transit schedule times and reduce the predictability of a transit vehicle approach. Detection can be added that calls for a special phase, such as a left-turn phase, when a transit vehicle is detected. This special phase will allow both the queue and transit vehicle to clear quickly. The variability and unpredictability associated with shared lanes make the signal priority system response less precise than those in exclusive lanes. Priority green time can be wasted adding delay to the non-transit routes.
Large traffic volumes on the cross-street may make signal priority for transit on the main street ineffective. This is further compounded when a transit route is also contained on the cross-street. The penalization of cross-street traffic to benefit the major street transit service may add costs that outweigh the benefits derived from transit priority.
LRT paralleling a major arterial street has been found to be independent of the operation of the arterial if the LRT is located at least 400 feet from the parallel arterial. If the LRT route is located greater than 400 feet from the parallel street, no special traffic signal applications to favor transit are required.
In CBDs, it may be best to avoid signal priority and adjust the traffic signal progression for transit speed. Signal priority in a tight grid system adds more
F-45 delay to the non-transit phases than is gained by the transit vehicle. This is especially true when one-way grid street systems are used. Signal priority for transit may be appropriate on two-way roadways in the CBD to expedite the movement in one direction or to allow for a special turning movement.
Guidelines: 1. Use transit priority when transit operates in an exclusive lane. 2. Use transit priority when cross-street bus volume is less than 5 in the peak hour. 3. Use transit priority when cross-street bus passenger volume is less than 200 in the peak hour. 4. Use transit priority when cross-street LRT volume is less than 2 trains in the peak hour. 5. Use transit priority when cross-street LRT passenger volume is less than 600 in the peak hour. 6. Use signal progression based on transit speeds in congested CBD.
Level and Type of Transit Service
Characteristics: Signal priority systems for transit are typically applied only to fixed route service, meaning transit service that operates on a regular route and schedule. Signal priority should be limited to transit routes with significantly high transit vehicle volume and ridership. Extremely large transit volumes in the peak-hour may make signal priority impractical as excessive priority calls add delay to the cross-street traffic that exceeds the benefits of priority. When AVI systems exist for transit vehicle detection, the ridership level can be evaluated on a dynamic basis. Then, signal priority can be used on a conditional basis and only implemented when predetermined thresholds are exceeded. Conditional priority can also be implemented with operator controlled emitters by instructing the transit operator to only call for priority when behind schedule.
A successful signal priority system will increase transit efficiency. With increased efficiency comes the completion of the transit route in less time. The transit agency must be prepared to change the transit schedule after signal priority is in place. If the schedule is not changed, the transit operator will negate the benefits of signal priority as he or she dwells when ahead of schedule.
Transit headways affect the quality of the signal priority system. Transit headways less than 5 minutes can add excessive delays to the cross-street traffic.
Guidelines: 1. Consider only fixed route service. 2. LRT volume should exceed 2 trains in the peak-hour on the transit route. 3. LRT passenger volume should exceed 600 passengers in the peak-hour on the transit route. 4. LRT volume should not exceed 10 trains in the peak-hour on the transit route. 5. Bus volume should exceed 5 buses in the peak-hour.
F-46 6. Bus passenger volume should exceed 200 in the peak-hour. 7. Bus volume should not exceed 50 in the peak-hour. 8. Conditional or demand based service should be initiated where AVI technology exists or where the transit operator has manual control over the emitter. 9. Bus transit headways less than 5 minutes or LRT headways less than 10 minutes may increase the delay and queues on the cross-streets beyond acceptable levels.
Stop/Station Characteristics
Characteristics: The location of transit stations and stop locations have important influences on signal priority. A farside stop should be used when a transit vehicle typically arrives on green or can obtain a "window stretching" priority at little cost to non- transit traffic. Nearside stop signal priority methods can be used when transit vehicles most often arrive during the red phase of the transit route. The transit vehicle can then load/unload passengers and use dwell time to await the next green phase. In an ideal situation, a nearside stop can be timed to coincide with a cross-street green time. This can reduce the amount of disruption from a signal priority application; however, the ability to coordinate arrival times with cross street signal phases may make signal priority for transit unwarranted.
The relative location of LRT facilities in the roadway cross-section can be a very important signal priority consideration. Traffic signals adjacent to median LRT operation can generally allow both parallel through movements and associated pedestrian phases to occur while a priority phase is green. LRT located on the side of the roadway can lead to vehicle conflicts with right-turning vehicles. Because of this, only the parallel vehicle phase in the opposite direction of the LRT can safely operate simultaneously with the transit priority phase.
In the most ideal situations, cross-street intersection spacing should be 1600 feet or greater on the transit route. Most often, intersection spacings are less than 1600 feet and variable. When cross-streets are located relatively close, the controllers should be connected so that the preemption can be passed from one controller to the next. Similarly, the close intersection spacing may create a situation where the pedestrian phase may be longer than the LRT call time. At these locations, the conflicting pedestrian phase is "suppressed" by relaying the pedestrian phase suppression call from the preceding intersection. This eliminates the clearance time required for pedestrians when a train is approaching and avoids the need for an LRT vehicle to slow for pedestrians at one intersection only to miss the preemption at the next.
Guidelines: 1. Must compute potential vehicle queues in relation to intersection spacings.
2. Must consider LRT vehicle length and stop locations in relation to intersection spacings.
F-47 3. Signal priority for transit has been successfully implemented at cross-street intersection spacings as low as 250 feet. 4. In highly congested locations, the bus transit stop location should be selected for queue jump applications.
Traffic Characteristics
Characteristics: The characteristics ideal for applications of signal priority are low volume roadways and low pedestrian volumes. One of the benefits of signal priority for transit is it also gives priority to general traffic traveling in the same direction on the major street as the transit vehicle. However, to achieve the transit signal priority, green time for major street left-turn and cross-street signal phases will need to be reallocated. Thus, additional green time must be available.
If the cross-street has been timed for signal progression, this reallocation of time may affect platooning. If these movements are heavily congested, the variability in arrival time will make signal priority inappropriate for unlimited transit signal priority. A key consideration in this trade-off analysis is whether transit signal priority will have a net reduction effect in person-trip delay at the intersection under consideration.
Transit priority reduces the capacity of the intersection and increases the intersection lost time. Signal priority for transit will be most effective when both the intersection level-of-service and transit approach street level-of-service are D or better. Signal priority is not an effective treatment when excessive queues are developed on the non-transit approaches. This is a common problem when cycle lengths are increased to add the additional priority phases.
Signal priority is not effective in highly congested areas. An evaluation of intersection and transit route V/C ratios, cross-street ADTs, and transit headways must be completed to determine the effectiveness of the proposed priority treatments. Calculate both total person delay as well as vehicle delay values in the analysis.
Transit operations designed to move with traffic progression as much as possible have been found to have a minimal impact on traffic operations.
Guidelines: 1. Cross-street traffic volumes should be 25,000 ADT or less. 2. A transit route on the cross-street reduces the acceptable cross-street ADT. 3. Transit route V/C ratio should be 0.85 or less. 4. Intersection V/C ratio should be 0.7 or less (0.5 desirable). 5. Decreasing transit headways reduce the acceptable V/C ratio and cross-street ADTs. 6. Computed queue lengths must be within available storage requirements. 7. Total person delay must decrease with signal priority. 8. Cycle length should be maintained with the addition of priority phasing.
F-48 Signal Control System
Characteristics: Signal priority for transit can be applied either in a coordinated or isolated traffic signal system along a corridor. If the signals are coordinated, some level of priority is already provided for transit, though transit vehicles may not be able to take full advantage because of stops along the corridor to load and unload passengers. Coordinated signal systems are more compatible with partial priority methods where the coordinated phase can still be maintained after making some minor adjustments to implement the transit signal priority.
Actuated signal systems provide more options for priority method selection. However, there is a greater probability that some priority methods will detrimentally affect cross-street traffic. With isolated signals, the fact that no consideration is made for coordination allows for additional priority options.
Even without the implementation of signal priority schemes, the simple reallocation of green time by providing a few more seconds of green to the transit phase (passive priority) can lead to the reduction in transit vehicle delay.
Guidelines: 1. Priority algorithms must be compatible with the signal control system. 2. Coordination can add benefits to the non-transit traffic during priority treatments. 3. Consider passive priority methods at isolated signal operation locations.
Transit Identification System
Characteristics: The presence of an AVI system provides the ability of determining whether a bus or LRT vehicle is ahead or behind schedule at a particular location. Transit agencies should only desire priority if transit vehicles are behind schedule. Transit operators should change and modify their transit schedules to reflect the time improvements obtained from signal priority systems. AVI technology can also be used to implement priority requests. Dynamic priority methods consider a database of transit route information and predict the arrival times of transit vehicles at downstream intersections. This allows for a more orderly and gradual adjustment in the signal phasing to accommodate the transit vehicle when it arrives.
Certainly, priority systems for transit can still be implemented when AVI technology is not present. Active priority systems using light and audio technology (Opticom, Sonic System, among others) provide effective methods of requesting priority for transit vehicles as they approach the intersection. Inductance loop detectors are also effectively applied. Consider technologies that require the least expensive emitter devices per transit vehicle. Regardless of the detection methods, the control algorithms must be able to differentiate between transit and emergency vehicle calls for priority and set a hierarchy that allows emergency vehicles to override the transit call.
F-49 Guidelines: 1. Use conditional priority when AVI technology exists. 2. Consider cost/benefit analysis results of other technologies when AVI is not present. 3. Include redundancies in the system in order to ensure that transit schedules are maintained if signal priority fails. 4. All transit vehicles must be equipped with the appropriate signal emitter devices. 5. Emitter cost can be up to $1500 per transit vehicle for infrared light emitting transit vehicle detection. 6. Emitter cost can be up to $200 per transit vehicle for ultrasonic sound emitting transit vehicle detection. 7. Loop detectors are estimated at $100 per loop.
F-50 STRATEGIES FOR OVERCOMING BARRIERS TO IMPLEMENTATION
This section describes strategies developed to overcome barriers to implementation of signal priority systems for transit. The author has developed these strategies to provide a more accurate understanding of the procedural improvements that future priority systems need to incorporate to produce a successful implementation. Many of the strategies at first appear obvious; however, these same strategies have been reportedly overlooked or omitted by transit agencies included in this investigation.
Strategies
Several strategies can be employed when facing barriers to implementation of a signal priority systems for transit operations. Table 10 provides a summary of these strategies. A detailed description of each strategy follows in numerical order.
Table 10. Strategies for Overcoming Barriers to Implementation.
Strategy Number Strategy 1 Complete the necessary preparation 2 Understand signal priority 3 Understand your transit system 4 Know your financial sources and options 5 Win the support of management 6 Establish a vendor relationship 7 Get advice from peers and transit professionals 8 Show the traffic engineers that priority works 9 Make sure the priority system is safe 10 Prove that it works
1. Complete the necessary preparation. Preparation for the many barriers that will be faced along the path to implementation of a signal priority system for transit operations cannot be overstated. The best way to overcome the many barriers is to thoroughly understand what is desired and be able to present this information in an intelligent and organized manner. Not being able to address the questions and concerns of management, traffic engineers, transit operators, and the public will likely prevent the priority system from becoming a reality.
F-51 Part of the necessary preparation also involves team building. A relationship must be established with all of the jurisdictions involved with the transit system and leaders within each organization identified. Appropriate understandings, agreements, and decision making processes need to be agreed upon. Operation and maintenance of the signal priority system should also be decided up front. The transit agency must be willing to address each agency’s concerns in a proactive fashion. Preparation will allow this to happen.
2. Understand signal priority. Too often, signal priority is narrowly viewed in only two applications, no priority and full preemption. There is however a tremendous array of signal priority treatments between these limits. The flexibility of signal priority schemes is one of its greatest assets and allows for applications in many different situations. It is also helpful to understand the different daily and intersection priority requirements and allow the variability of different priority treatments to fit each requirement. It is virtually impossible to anticipate during the design process all of the variations in operating conditions that will be experienced, even through advances in simulation techniques. Understanding signal priority will allow the appropriate strategy to be optimally deployed for each situation.
3. Understand your transit system. Making sure that the signal priority system for transit operations is a viable alternative before pushing for implementation is important. Each transit route should be analyzed to assure that the existing and proposed traffic and geometric conditions satisfy the criteria and guidelines necessary for signal priority systems. If signal priority will not work for your system, or if major changes to the system are required to make signal priority a realistic venue, this should be determined in the initial phase of the investigation. Signal priority is not effective in all situations.
4. Know your financial sources and options. The signal priority system surely cannot be implemented without appropriate funding. This is often the most significant barrier faced by transit operators. Investigate sources of local, state and federal funds that can be used to develop the priority system. Know who are the appropriate people who must champion this system to obtain the funding. Know the current levels of FTA funds and sources of federal transit grants. Also, have clear cost estimates determined so that when the funds become available, the total dollar amount necessary to implement the system is well understood.
5. Win the support of management. Management can break through many barriers that others cannot. Management will play a significant role in establishing relationships among all of the agencies involved, identifying funding sources, assigning the people necessary for system development, and convincing the public that signal priority is a wise allocation of funding. No system has been reported to be implemented without a member of management or management as a whole pushing for the priority system.
6. Establish a vendor relationship. One of the best ways to develop a signal priority system for transit operations that is appropriate for the given situation is to work with vendors who are experienced in the hardware, software, and the necessary components required for implementation. This relationship will provide some of the necessary knowledge that is crucial for overcoming barriers. Many vendors are also interested in placing their systems in demonstration projects. By working with vendors, the initial system can be placed for a below
F-52 market cost with the hope that the demonstrated success will lead to further development of the priority system.
7. Get advice from peers and transit professionals. Along with vendors, use the knowledge obtained by peers who have successfully implemented a signal priority system for transit. Find out how they obtained their goals, what barriers were faced, and what they learned along the way. Learn how they sold the signal priority system to the public. This knowledge can help avoid potential pitfalls along the way that otherwise would be unanticipated.
8. Show the traffic engineers that priority works. The technical staff in traffic operations can be one of the biggest supporters or one of the largest barriers to the implementation of signal priority systems for transit. A number of signal priority systems have been slowed or halted by traffic engineering colleagues who fail to see the benefits of transit priority. Often, the potential impacts to non-priority traffic are magnified in the minds of traffic engineers whose primary objective is to minimize average vehicle delay at signalized intersections without consideration of average person delay. The simulation tools that are currently available may be a way to demonstrate effectively that the proposed transit priority systems will provide the benefits promised and add little detrimental effect to traffic operations. Also, new technologies such as AVI provide methods of conditional priority which can minimize the impact of priority to non-transit intersection approaches. By working closely with traffic engineers and effectively showing the traffic engineering people that the priority system is beneficial, many barriers to implementation can be overcome. This may be accomplished by inviting the traffic engineer to be a co-champion of the project, or as a minimum, a key member of the design and implementation team.
9. Make sure the priority system is safe. Nothing will stop a public project faster than a lack of safety considerations to the traveling public. Safety is always a concern of both public officials and the city’s legal team. All potential failure modes must be evaluated and methods for overcoming these problems understood. Always, "fail safe" methods must be the overriding outcome of system failures with "fail critical" outcome only as a result of unique or uncontrollable human error. Safety must be the first and last consideration if this barrier is to be avoided. An unsafe system will turn the public against signal priority and will undoubtedly reduce the probability of additional development.
10. Prove that it works. The most effective way to overcome barriers to implementation is through demonstration of the effectiveness of the system. Prove that it works. This method has been successfully used in Portland. Where city traffic engineering staff has been resistant to granting LRT priority, Portland has convinced local city staff to accept very short term transit signal priority demonstrations at selected crossings. These projects generally last no longer than a month. After the transit priority signal system has been in operation, and local jurisdictions observe little negative effect on their intersection operations, they ultimately approve the permanent application of the transit signal priority system. This philosophy can be applied to bus priority methods as well.
F-53 The development of field tests will not always be feasible. Thus, the development of transit priority system simulation may be appropriate. This technique will be much less costly than field implementation yet still can convince the traffic engineer that signal priority works.
Once a priority system is operational, the public must be sold on the benefits of signal priority. The public must support the need for transit priority over general purpose traffic. Many psychological methods designed to change public opinion have been employed. Kitsap County near Seattle has used successful promotional campaigns to a point where Opticom is a household word and is looked upon as a great benefit to the community. When the public is convinced that signal priority works, barriers to implementation can be overcome and signal priority for transit will have a long and happy life.
F-54 CASE STUDY: KING COUNTY, WASHINGTON
King County is a large metropolitan area located on Puget Sound in Washington State. Covering more than 2,200 square miles, King County is nearly twice as large as the average county in the United States. A number of large cities are located in King County including Seattle, Bellevue, and Kirkland. Given this large area of coverage, providing transit service around the county introduces a number of challenges. A map of King County is shown in Figure 13 (49).
King County Department of Metropolitan Services, formerly known as King County Metro, is in the final stages of implementing a traffic signal priority system for bus transit (50). The initial signal priority system will contain 27 signalized intersections located on Rainier Avenue and Highway 99. These intersections are currently operated by the City of Seattle, the State of Washington, and the City of Bellevue. The Seattle area is also in the process of implementing an AVI system as part of their ITS development. The AVI system, which is scheduled to become operational in 1997, will provide the necessary mechanism for detecting transit vehicles and requesting signal priority when appropriate. At the time of this writing, King County has been successful in bringing the signal priority for transit project to the implementation stage.
Application of Strategies for Overcoming Barriers to Implementation
This section provides an application of the strategies developed for overcoming barriers to implementation of signal priority systems. The strategies will be applied to the traffic signal priority for bus transit project in King County. Each of the ten strategies will be considered.
1. Complete the necessary preparation
King County has spent over three years developing the signal priority system concept. Much of the initial investigation was focused not on signal priority but on how communication will be established between the transit vehicles and the traffic signal controllers. This question was identified by the local agencies and traffic engineers as one of the primary barriers to overcome. A regional agreement between all of the agencies has been completed allowing a unified approach to the remaining aspects of the project. Thus, King County has addressed the questions and concerns of management, traffic engineers, transit operators, and the public which completes the first step in making the priority system for transit a reality.
Team building is a large component of the project development process. Tremendous effort has been placed in addressing the concerns of the various jurisdictions involved and working through each issue. Although many technical issues were identified, the primary initiative has been to establish a consensus to the concept of signal priority. With over 30 agencies affected by the development of signal priority systems throughout the region, this is a significant challenge. King County has focused on consensus building between the three primary agencies involved in this initial project. Other agencies are allowed to participate and are brought in as they begin the development in their jurisdiction. Once the consensus was obtained, working out the technical details became much less demanding. Thus, a lot of time and effort in the preparation stage of this project has been
F-55 Figure 13. King County Map (50).
F-56 spent on developing the relationships necessary to overcome barriers later in the process which satisfies the second major component of the first strategy identified.
2. Understand signal priority
As mentioned, a tremendous amount of work went into the development of the signal priority concept and how the communication between the transit vehicle and signal controller would be established. King County is a large and complicated metropolitan area which requires a more detailed understanding of the priority concept.
King County looks at the development of signal priority for transit operations as an evolutionary process. They have added engineers to the staff and provided them with training in traffic signal concepts in an effort to communicate with and understand the concerns of the traffic engineers. King County also provides training for their staff in developing a traffic engineering and signal priority vocabulary.
A large amount of transit funds have been spent in the analysis and simulation of various aspects of the signal priority system. This has allowed King County to successfully address many of the concerns of the jurisdictions and agencies involved. This has also been completed as a benefit to the city traffic engineers in the region as many of them do not have the staff to conduct their own analysis. King County is fully aware of the wide array of signal priority methods available and are planning to bring in transit experts to address this concern. Thus, through the use of simulation and consultants, King County understands signal priority and is applying strategy 2.
3. Understand your transit system
The proposed transit network contains many different intersection characteristics ranging from low volume isolated intersections to high density CBD intersections. Clearly, the signal priority methods should not be the same at each intersection and this is well understood. There is also the possibility that signal priority will not work in some of the CBD intersections. King County realized that a common technology for implementing signal priority was required because of the large number of different jurisdictions involved. The AVI system allows for standardization between all of the transit fleets. Thus, King County has taken a big step forward by selecting the AVI technology as the standard for their signal priority system.
A detailed list of MOEs has been established to evaluate the traffic engineering issues related to signal priority before and after installation of the priority system. After the priority system is operational, detailed quantitative values will be determined to assist the traffic engineering community in evaluating the appropriateness of future signal priority locations. King County will be assured that the signal priority system will meet the needs of its transit system in all sections of the county.
F-57 4. Know your financial sources and options
The development of this initial stage of the signal priority system in King County is being completed primarily with local funds. Grants from FTA also provide a portion of the funding. King County continues to look to FHWA and other federal agencies for sources of new funds to expand the system.
King County has set up a procurement procedure that includes an agreed upon price list that contains a no escalation clause. All of the hardware components necessary for the signal priority and the AVI system are included. This will allow any public agency in the State of Washington to purchase items from this list as signal priority systems are installed. Initial estimates are between $20,000 and $30,000 per intersection for the necessary equipment and installation. Thus, King County has been successfully applying strategy 4 by estimating the cost of the system and seeking funds from all government levels.
5. Win support of management
King County has taken a different approach in this area. The leadership of the signal priority program has been maintained at the lower management and staff level. The reason for this is to maintain the working relationship with the traffic engineers. The traffic engineers remain uncomfortable with the idea of signal priority. Adding management and political pressure at this point will only add to their anxiety. Once the initial priority system for transit is in place and the traffic engineers are comfortable with the system, upper management and the political process can be brought in to lead the next phase of the priority system development. Thus, King County is applying strategy 5 and gaining the lower management and staff level support with the first implementation section.
6. Establish a vendor relationship
King County is just embarking on strategy 6. Vendors will be invited to a brainstorming session to discuss the many signal priority methods appropriate for the King County transit system. This is a mutually beneficial endeavor as it provides the opportunity for the vendors to become involved in the process and promote their products while they share they their ideas and experiences with King County. Ultimately, they hope to develop a partnership with a vendor(s) that will provide cost effective development of the priority system.
7. Get advice form peers and transit professionals
This project has taken advantage of the resources available in the Seattle area. A committee of transportation professionals was established including State and local officials, many of which were champions of the project. Qualified consultants were available and called upon when needed. King County intends to invite experts in signal priority systems from around the country to a brainstorming meeting. Their primary objective will be to identify the potential range of control strategies and priority methods which are feasible throughout the system. Thus, this peer review of experts from other locations around the country will be a major step in employing strategy 7.
F-58 8. Show the traffic engineers that priority works
King County took the approach during the initial stages of the project that the traffic engineers throughout the region are the primary barrier to installation. The first project objective was to develop a common technology for transit detection. This included working with the traffic engineers in developing items ranging from what will be placed in the controller cabinets to a common protocol of information provided for decision making. It took monthly meetings for over two years to convince the traffic engineers that the signal priority equipment placed into the controller cabinet was not something foreign. Much of the work was directed at getting the traffic engineers beyond the Opticom priority methods into the AVI technology which allows for both control of the system and location specific applications. King County is comfortable with allowing the development of the signal priority system to become a traffic initiative rather than a transit initiative since traffic is where the system ultimately has to reside. However, they also realize that the traffic engineers can limit the benefits of signal priority to transit by controlling the green time that is available.
Based on this working relationship developed over a 24 month procurement process and through an interagency board, all parties agreed on the AVI and signal priority system. King County transit allowed the traffic engineers to develop their own standards and expectations for this technology. Partnering with the traffic engineer has allowed King County to successfully obtain the signal priority system for transit. Thus, by gaining the input of the traffic engineers, strategy 8 is being achieved.
9. Make sure the priority system is safe
Safety of the priority system was an initial concern of some of the agencies involved. However, operation of the priority system under AVI control minimizes many of the safety concerns. Very rigorous traffic signal controls have been established to prevent unsafe signal operations. The safety of traffic operations at each intersection under signal priority will not be jeopardized in lieu of signal priority. Thus, maintaining a safe operation with a successful signal priority system has been the main goal that has been established to achieve strategy 9 right from the start.
10. Prove that it works
King County takes a unique approach in admitting that they are not sure how the signal priority system will work. They are confident that, along with the traffic engineers in the region, they can make the signal priority system for transit successful. The priority system under AVI control has enough built in flexibility that allows the traffic engineers to make the necessary adjustments to improve the priority system performance. The only unknown that remains is how much benefit can the system provide. It is believed that the time saving benefits of signal priority will eliminate the short-term needs of transit fleet expansion. If this is realized, the benefits of the signal priority system will far exceed the costs.
King County has taken a position that the system will work without multiple demonstration projects. In fact, demonstrations projects were avoided because of the multijurisdictional
F-59 relationships that are currently established. Demonstration projects in each jurisdiction would of been of interest; however, because of the need to standardize the equipment used throughout the county and transit fleet, multiple demonstration projects would be counterproductive. Thus, King County is using a phased implementation to achieve strategy 10.
Summary
King County has successfully used many of the strategies identified to begin the implementation process of the signal priority system for bus transit. Their primary focus has been on the traffic engineers and getting each one of them to buy into the priority concept. However, team building, developing a thorough understanding of the system, and obtaining advice of vendors and transit professionals have been important strategies. Beyond the strategies identified, the implementation of a signal priority system for any major project requires the right combination of technology and people, at the right time. Now is the right time for King County.
CONCLUSIONS
Traffic signal priority systems for transit operations have been shown to improve transit operations by reducing delay and increasing the average speed of transit vehicles. It has been shown that transit can indeed be integrated into an arterial network and operate harmoniously with other traffic under signal priority applications. In spite of this, there remains resistance to the implementation of priority systems. Numerous factors affect the viability of priority systems. These include institutional and agency control, operational factors, existing vehicle and transit volumes, and human factors considerations. Traffic signal priority is also not universally understood. The combination of these factors will determine if signal priority is an acceptable strategy for a given transit system. If signal priority is feasible, identifying the barriers to implementation, developing strategies for overcoming these barriers, and following characteristics, guidelines and criteria established by successful priority systems will allow signal priority for transit operations to be successfully implemented. This has been demonstrated in King County, Washington.
F-60 ACKNOWLEDGMENTS
This report was prepared for the graduate summer course CVEN 677 Advanced Surface Transportation Systems at Texas A&M University. The author would like to express his gratitude to Dr. Conrad Dudek, the course instructor, for providing the opportunity to meet and work with the diverse group of transportation professionals. The author would like to especially thank Mr. Walter Dunn and Mr. Tom Werner, who served as my professional mentors, for their assistance, guidance, and encouragement throughout the preparation of this report. A special thanks also goes out to the other professional mentors: Les Jacobson, Jack Kay, Colin Rayman, and Ginger Gherardi for their assistance and advice. The combination of these individuals made this one of the most rewarding professional experiences of my life. Finally, a loving thanks goes out to my wife Kati and son Gabriel who continue to make sacrifices in support of my academic pursuit.
Thanks also goes to the following people who contributed to this effort through the interview process:
Mr. Kern Jacobson - PB Farradyne Mr. Dick Hayes - Kitsap Transit Ms. Ellen Bevington - King County Department of Metropolitan Services Mr. Kang Hu - LADOT Mr. Mike Wendtland - JHK Associates Mr. Graham Carey - JRH Associates Mr. Mike Krasny - Sonic Systems Mr. Jeff O'Brien - Consolidated Traffic Control (Opticom) Mr. Glenn Commons - PreEmption Marking Incorporated Mr. Bill Kloos - City of Portland Mr. Les Kelman - Metro Toronto Transit Texas Office of FTA Ms. Kay Fitzpatrick - Texas Transportation Institute Dr. Dan Fambro - Texas A&M University
F-61 REFERENCES
1. Bauer, Thomas, Mark P. Medema, and Subbarao V. Jayanthi. Testing of Light Rail Signal Control Strategies by Combining Transit and Traffic Simulation Models. Transportation Research Record 1494, TRB, National Research Council, Washington, D.C., 1994, pp. 155- 160.
2. Daniel, Janice. Signal Priority for Public Transit Vehicles Using Advanced Traffic Control Systems: A Comparative Evaluation of ATSAC, SCATS and SCOOT. CVEN 689, Transportation Information and Control Systems Design, Southwest Region University Transportation Center, Texas Transportation Institute, The Texas A&M University System, College Station, Texas, August 1992.
3. Location and Design of Bus Stops. Draft Final Report, TCRP, Texas Transportation Institute, College Station, Texas, April 1996.
4. Sunkari, Srinivasa R., Phillip S. Beasley, Thomas Urbanik II, and Daniel B. Fambro. Model to Evaluate the Impacts of Bus Priority on Signalized Intersections. Transportation Research Record 1494, TRB, National Research Council, Washington, D.C., 1994, pp. 117-123.
5. Evans, H. and G. Skiles. Improving Public Transit Through Bus Preemption of Traffic Signals. Traffic Quarterly. Vol. 24, No. 4, October 1970, pp. 531-543.
6. Evaluation of UTCS/BPS Control Strategies. Federal Highway Administration, U.S. Department of Transportation, March 1975.
7. Tarnoff, P.J. The Result of Urban Public Traffic Control Research: An Interim Report. Traffic Engineering, Vol. 45. No. 4, April 1975.
8. Jacobson, Kern L. Transit Signal Priority Treatments in the Puget Sound Region. Proceedings of the 1993 Pacific Rim TransTech Conference, Volume 1, ASCE Third International Conference on Applications of Advanced Technologies in Transportation Engineering, ASCE, New York, NY, pp. 272-278.
9. Khasnabis, Snehamay, Gangula V. Reddy, and Syed Khurshidul Hoda. Evaluation of the Operating Cost Consequences of Signal Preemption as an IVHS Strategy. Transportation Research Record 1390, TRB, National Research Council, Washington, D.C., 1993, pp. 3-9.
10. Hounsell, N. B. and J. P. Wu. Public Transport Priority in Real-Time Traffic Control Systems. Proceedings of the 1995 4th International Conference on the Applications of Advanced Technologies in Transportation Engineering. ASCE, New York, NY, pp. 71-75.
11. Hounsell, H. B. Bus Priority: Techniques and Evaluation. Public Transport Planning and Operation, Volume P331, PTRC Education and Research Services, Sussex, England, 1990.
F-62 12. Nelson, J. D., D. W. Brookes, and M. G. H. Bell. Approaches to the Provision of Priority for Public Transport at Traffic Signals: A European Perspective. Traffic Engineering and Control, 34(9), 1993, pp. 426-428.
13. Piper, J. and P.R. Cornwell. Design for Public Transport. Traffic Engineering Practice (3rd Edition), Monash University, Melbourne, 1984, 214-228.
14. Lee, Leo K., Warren Tighe, and Allen Albers. Traffic/LRT System Integration for the Blue Line in Los Angeles. ITE 1990 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 163-167.
15. Mowatt, Magnus G. Transit Signal Priority: A Regional Implementation. ITE 1995 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 85-91.
16. Cornwell, P. R., J. Y. K. Luk, and B. J. Negas. Tram Priority in SCATS. Traffic Engineering and Control, 27(11), 1986, pp. 561-565.
17. Kloos, William C., Alan R. Danaher, and Katharine M. Hunter-Zaworski. Bus Priority at Traffic Signals in Portland: The Powell Boulevard Pilot Project. ITE 1994 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 420-424.
18. Elson, Jon M. And Charles A. Felix. Light Rail Impacts on Surface Street Operation in Santa Clara County. ITE 1991 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 205-214.
19. Bishop, C. M., D. B. Richardson, G. W. Carr, and D. S. McMillan. Transit Signal Priority - Another Look. ITE 1988 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 228-232.
20. Khasnabis, Snehamay, Gangula V. Reddy, and Bharat B. Chaudry. Signal Preemption as a Priority Treatment Tool for Transit Demand Management. 1991 Vehicle Navigation and Information Systems Conference Proceedings, Part 2, IEEE, Society of Automotive Engineers, Warrendale, PA, pp. 1093-1104.
21. Howie, Donald J. And Richard West. Bus Priority Revisited. ITE 1991 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 471-475.
22. McGinley, F.T. Active Tram Priority in Coordinated Signal Systems. Australian Road Research, Vol. 13, No. 3, 1983, pp. 173-184.
23. Walters, Carol H., Steven P. Venglar, Daniel B. Fambro, and Janice R. Daniel. Development of Analytical Tools for Evaluating Operations of Light-Rail At-Grade within an Urban Signal System - Interim Report. Research Report 1278-1, Texas Transportation Institute, College Station, Texas, 1993.
F-63 24. Telephone interview with Jeff O’Brien and corresponding Company Literature, Consolidated Traffic Control, Arlington, TX, June 1996.
25. Telephone interview with Mike Krasny and corresponding Company Literature, Sonic Systems Corporation, Vancouver, BC, June 1996.
26. Korve, Hans M. and Maryanne M. Jones. Light Rail At-Grade Crossing Operations in CBD Environments. Presented at the 73rd Annual Meeting of the Transportation Research Board, TRB, National Research Council, Washington, D.C., 1994.
27. Argabright, Teri. How Seattle Created One System Out of Many. Metro Magazine, May/June 1996.
28. Mainline Traffic Signal Priority Study Phase V - Demonstration Project. Toronto Transit Commission, Final Report, April 1991.
29. Telephone interview with staff members of the Los Angeles Department of Transportation, LADOT, Los Angeles, CA, July 1996.
30. Federal Transit Agency, Internet Web Site, Http://www.fta.dot/gov/fta/library/money/fy96cut/ bfflotp.htm, Washington, D.C., 1996.
31. Ramsdell, Edward L. Tort Liability and IVHS: A Transportation Industry Analyst’s Perspective. Surface Transportation: Mobility, Technology, and Society, Proceedings of the IVHS America 1993 Annual Meeting, Washington, D.C., pp. 411-417.
32. Telephone interview with Dick Hayes, Kitsap Transit, Seattle, WA, August 1996.
33. Teply, Stan. Interaction of Two Control Systems: The Edmonton LRT Example. Traffic Monitoring and Control Systems, Proceedings of the 1983 Engineering Foundation Conference, Henniker, New Hampshire, July 1983, pp. 43-61.
34. ITE Committee 6A-42. LRT Grade Separation Guidelines, ITE, Washington, D.C., 1992, pp. 1-37. (Chairman Thomas J. Stone)
35. Kloos, William C. Traffic Control and LRT: How We Do It In Portland. ITE 1988 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 185-187.
36. Hoey, William F. and Herbert S. Levinson. Signal Preemption by Light Rail Transit: Where Does it Work? ITE 1989 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 330-334.
37. Telephone interview with Kern Jacobson, PB Farradyne, Seattle, WA, July 1996.
F-64 38. Stone, Thomas J. and William A. Wild. Design Consideration for LRT in Existing Medians: Developing Warrants for Priority Treatments. Transportation Research Board Special Report 195, TRB, National Research Council, Washington, D.C., 1982, pp 170-175.
39. ITE Committee 6Y-37. Guidelines for Design of Light Rail Grade Crossings, ITE, Washington, D.C., 1992, pp. 1-64. (Chairman Hans W. Korve)
40. Tighe, Warren A. and Larry A. Patterson. Integrating LRT into Flexible Traffic Control Systems. TRB State-of-the-Art Report 2, TRB, National Research Council, Washington, D.C., 1985, pp. 213-219.
41. Fox, Gerald. Light Rail/Traffic Interface in Portland -- The First Five Years. Presented at the 1992 TRB Light Rail Conference, Calgary, Canada, May 1992, pp. 1-17.
42. Lee, Leo, and Paul Taylor. At Grade Light Rail/Traffic Operational Interface Features. American Public Transit Association, Rapid Transit Conference, Buffalo, New York, Jun 1988.
43. Berry, Richard A. And James C. Williams. Traffic Characteristics of At-Grade Light Rail Crossings. ITE 1989 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 321-325.
44. Larwin, Thomas F. and Harold Rosenberg. Traffic Planning for Light Rail Transit. ITE 1978 Compendium of Technical Papers, ITE, Washington, D.C., pp.236-242.
45. Lancaster, Tom R. Light Rail Transit Preemption of Actuated Signals. ITE 1989 Compendium of Technical Papers, Institute of Transportation Engineers, Washington D.C., pp. 335-337.
46. Fox, C. Tram Priority in a Coordinated Traffic Signal System. ARRB Proceedings, Vol. 12, Part 4, 1994, pp. 160-170.
47. Wu, J. and M. McDonald. The Effects of At-Grade LRT at Signalized Intersections. ITE 1994 Compendium of Technical Papers, Institute of Transportation Engineers, Washington, D.C., pp. 481-485.
48. PTV System Promotional Material. PTV System, Karlsruhe, Germany, 1995.
49. Venglar, Steven P., Daniel B. Fambro, and Thomas Bauer. Validation of Simulation Software for Modeling Light Rail Transit. Transportation Research Record 1494, TRB, National Research Council, Washington, D.C., 1994, pp. 161-166.
50. King County, Internet Web Site, http://www.metrokc.gov/about.htm, Seattle, WA, 1996.
51. Telephone interview with Ellen Bevington, King County Department of Metropolitan Services, Seattle, WA, August 1996.
52. Collins, Darwin. The Unofficial DART Light Rail Page, http://www.fastlane.net/homepages/
F-65 dcollins/ morepics.shtml, Dallas, Texas, 1996. David A. Noyce received his B.S. and M.S. in Civil and Environmental Engineering from the University of Wisconsin-Madison in May of 1984 and May of 1995, respectively. David is a licensed professional engineer in the State of Wisconsin and has spent 10 years working in the transportation engineering industry for employers including the Illinois Department of Transportation and a number of Midwest based consulting engineering firms. David’s last position was as manager of a 10 person transportation engineering group in an 80 employee consulting engineering firm. David began work towards his Ph.D. in June of 1995 and is currently employed by the Texas Transportation Institute. David is an active member of the Wisconsin Society of Professional Engineers where he has held the positions of statewide membership director and local chapter president-elect. David is also a member of the American Society of Civil Engineers. David is involved in University activities, including the Institute of Transportation Engineers, where he has been recently elected as the Texas A&M Student Chapter President for the 1996-97 academic year. David has published work in both the transportation and construction areas of civil engineering, and has received a number of fellowships and scholarships. His areas of interest include: traffic operations, geometric design, transportation safety, and construction operations of transportation facilities.
F-66 CHALLENGES AND GUIDELINES FOR IMPLEMENTING ADVANCED PARKING INFORMATION SYSTEMS IN THE UNITED STATES FOR DAILY DOWNTOWN TRAFFIC
by
Kelly D. Parma
Professional Mentor Leslie N. Jacobson, P.E. Washington State Department of Transportation
Prepared For CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, TX
August 1996 SUMMARY
The problems created by parking congestion exist in many industrialized countries around the world. In solving the parking problem in the United States, many cities have continued to build more parking facilities. Meanwhile, cities in Europe, Germany and Japan have used innovative methods, such as Parking Guidance and Information (PGI) systems, in creating a more efficient parking system without the need to build more facilities. Twenty years after the first PGI system was installed in Germany, two cities in the United States have determined that systems similar to the systems utilized in cities in other countries can be used in the US to solve the problems associated with parking. In the United States, these parking systems are referred to as Advanced Parking Information (API) systems and have been installed in Pittsburgh, Pennsylvania and St. Paul, Minnesota. These systems were installed to relieve parking congestion in the downtown areas which was created by special events.
API systems can provide benefits to the cities that implement them in a variety of ways. The information that is provided to motorists allows them to make an informed decision on which parking facility to use and how to arrive there. These systems can redistribute parking demand among the parking facilities, thereby making more effective use of the existing capacity of the parking facilities located in the downtown area. While there are many issues that must be resolved before an API system is even installed, the results from other countries have indicated that the majority of users think that an API system is useful.
In order to implement more of these systems in the United States, there are challenges that must be overcome. These include encouraging cooperation between public and private sectors, gaining funding to cover the cost of these systems, as well as overcoming the mentality of building more facilities when empty parking spaces are hard to find. In addition, awareness of these systems must be generated to provide another alternative to building more parking facilities. Most important, the public must accept any system that is implemented, as they will be the determinants of whether a system is successful or not.
General guidelines for implementing an API system for downtown daily traffic in any metropolitan area in the United States are provided in this report. These guidelines are based on the experiences of others who have installed API systems in the US and overseas. The guidelines provided should allow transportation professionals the ability to overcome the challenges in implementing an API system to achieve success in solving the parking problems of the downtown area. These guidelines were then applied as a case study to San Antonio, Texas.
G-ii TABLE OF CONTENTS
INTRODUCTION ...... G-1 Problem Statement ...... G-1 Objectives ...... G-2 Scope ...... G-2 Study Approach ...... G-2
OVERVIEW OF ADVANCED PARKING INFORMATION SYSTEMS ...... G-3 How the API System Works ...... G-3 Benefits of API Systems ...... G-3 Results From Other Countries ...... G-4 Germany ...... G-4 England ...... G-5 Japan ...... G-5
API SYSTEMS IN THE UNITED STATES ...... G-6 Pittsburgh, Pennsylvania ...... G-6 St. Paul, Minnesota ...... G-7
RESULTS OF TELEPHONE INTERVIEWS ...... G-8 Interview Process and Participants ...... G-8 Interview Results ...... G-9
CHALLENGES IN IMPLEMENTING API SYSTEMS IN THE UNITED STATES .G-13 Cooperation Between Public and Private Sectors ...... G-13 Cost / Funding ...... G-14 Creating Awareness of API System ...... G-14 Overcoming “Build” Mentality ...... G-15 Gaining Public Acceptance ...... G-15
API SYSTEM IMPLEMENTATION GUIDELINES ...... G-16 Stage 1: Preliminary Planning ...... G-16 Stage 2A: Design and Pre-Installation ...... G-19 Stage 2B: Marketing Strategy ...... G-21 Stage 3: Final Implementation ...... G-22
IMPLEMENTATION GUIDELINES FOR SAN ANTONIO, TEXAS ...... G-23 City of San Antonio ...... G-23 TransGuide ...... G-23 Stage 1: Preliminary Planning ...... G-23 Stage 2A: Design and Pre-Installation ...... G-26 Stage 2B: Marketing Strategy ...... G-31 Stage 3: Final Implementation ...... G-31
G-iii CONCLUSIONS ...... G-33
RECOMMENDATIONS ...... G-34
ACKNOWLEDGMENTS ...... G-35
REFERENCES ...... G-36
APPENDIX A ...... G-40
APPENDIX B ...... G-41
APPENDIX C ...... G-42
G-iv INTRODUCTION
The goals and objectives of the Intelligent Transportation Systems (ITS) program are to enhance the productivity and mobility of the highway system, as well as to improve its safety. ITS is also intended to increase the efficiency of highways and reduce the energy and environmental impact associated with vehicles and roads (1). As part of the ITS program, six categories of user services have been developed. These include (1):
• Travel and Traffic Management; • Public Transportation Management; • Electronic Payment; • Commercial Vehicle Operations; • Emergency Management; and • Advanced Vehicle Safety Systems.
The need to provide motorists with information on the status of parking in congested areas is an aspect of traveler services information within the category of travel and traffic management. While the idea of providing advanced parking information to motorists is part of the architecture of ITS, there has been little utilization of this idea in the United States.
As a result of not informing motorists of the current parking availability in the downtown area, congestion can occur. This congestion is partly caused by the motorists’ perception that there are not enough parking spaces in the downtown area which can affect the flow of traffic in this area. This flow is hindered either by queued vehicles waiting to enter a full parking facility or by vehicles circulating around the downtown area searching for an open parking space. Studies in other countries have shown that between 15 to 30 percent of all drivers circulating within the downtown area are searching for available parking spaces (2, 3). In addition, travel times for those motorists searching for an open parking space can constitute anywhere from 25 to 40 percent of their total travel time (4, 5).
Problem Statement
In many metropolitan areas of the United States today, there is a perceived lack of available parking in the downtown area. This “lack” of parking is compounded by the presence of unfamiliar drivers, i.e., visitors and tourists, who approach the downtown area without knowledge of where they can and should park or the availability of spaces at these parking facilities. While these visitors may be unfamiliar with the street system of the downtown area, there are usually street maps available for their use, as well as traffic reports detailing congestion. Unfortunately, a map of parking facilities usually does not exist, nor is information provided on the availability of parking. This perception of lack of parking spaces and the presence of unfamiliar drivers can result in lost time and frustration for motorists while they search for a parking space, as well as a reduction in the efficient flow of traffic in the downtown area. Over time, as the number of vehicles traveling to the downtown area increases, this situation can only worsen if no improvements are made. Therefore, there is a need to improve the parking situation in the downtown area in some cities in the United States.
G-1 One solution to this problem is through the utilization of an API system. Using such a system, motorists (familiar and unfamiliar) can be better informed of both the availability and the location of parking facilities in the downtown area. While cities in other countries have implemented these types of systems for the past twenty years, the first implementation of such a system in the United States occurred only two years ago. If API systems were utilized more in the United States, motorists would be better informed of the status of parking in the downtown area and could reap some of the benefits of API systems that motorists in other countries have attained. In order to implement more API systems in the United States, challenges to such systems must be identified. In addition, guidelines must be provided to allow for proper implementation of these systems.
Objectives
The objectives of this paper were to:
1. Exhibit the potential benefits of implementing API systems in major metropolitan areas in the United States by documenting the results of systems used in other countries. 2. Determine the challenges which exist in implementing an API system in major cities in the United States. 3. Provide general guidelines for implementing an API system for the downtown area of any city in the United States. 4. Apply these guidelines to a case study of API system implementation for the downtown area of San Antonio, Texas.
Scope
The scope of this project was limited to providing guidelines for implementing API systems in cities across the United States for daily downtown traffic. This involves trips which are made to the downtown area for business, errands or to visit attractions. These guidelines were applied for implementation of an API system for downtown daily traffic in San Antonio. Although special events in the downtown area may have an impact on parking in this location, this research did not include special events parking because such a study had been conducted previously (6).
Study Approach
The objectives of this report were achieved by completing three main tasks. The first task involved conducting a literature review in examining the state-of-the-art of API systems. This review was used in determining the results of API systems overseas, as well as exploring the possible benefits of using these systems. The second task consisted of telephone discussions with transportation professionals from around the country on API systems. The transportation professionals offered their opinions on API systems and helped in identifying challenges that exist in implementing these systems in cities across the United States. The third and final task involved conducting telephone interviews with city transportation, parking and planning officials and private parking facility managers in determining the current parking situation in downtown of their city and their concerns with API systems. Additional discussion was held with an official from the City of San Antonio Parking Division in preparing the API system implementation guidelines for that city.
G-2 OVERVIEW OF ADVANCED PARKING INFORMATION SYSTEMS
The first API system was implemented in Aachen, Germany over twenty years ago (4). Since then, the number of systems have grown to over 75 locations, including two in the United States (5,6). Since API systems are relatively new to the United States, it is important to provide some background on these systems.
How the API System Works
Providing information regarding real-time parking availability in the downtown area is a major aspect of an API system. Therefore, the API system must determine the number of cars that are using each parking facility. This is accomplished by first obtaining the capacity of each parking facility in the downtown area. Loop detectors or sensors are placed at the entrances and exits of the parking facilities to determine the number of cars that have entered and left the facility. Finally, simple addition and subtraction are used in determining the number of parking spaces that are available at each parking facility.
This information is provided to a central control center, usually the advanced traffic management center in the city, and then is provided to motorists. Motorists can receive this information in a variety of ways, the most common being through the use of electronic variable message (dynamic) signs along the road. In addition, parking availability information can be presented to motorists through other means, such as television, telephone dial-up, radio, or through in-vehicle navigation systems (8). The communication link between the equipment in the parking facilities, the control center and the dynamic signs can occur through the use of hard wiring or wireless links (2).
While each API system differs, most of the systems in place resemble the system architecture that is described here. The downtown area of the city is divided into different locational zones, which can be identified by using different colored signs. On the main roadways leading into the downtown area, real-time data on the availability of parking is indicated for each zone in downtown using electronic variable message signs. At major intersections leading to each zone of the city, the number of available spaces at individual facilities within that zone and directions to those facilities are provided using the same type of electronic variable message signs as before. After the motorists have entered their desired zone, static signs are used in guiding the motorists to the parking facilities (2,9).
Benefits of API Systems
The benefits of an API system are especially obvious during periods of peak activity in the downtown area. However, the information that is provided to the motorists through this system can be beneficial at all times. Under any condition, motorists should see the benefits in the reduction of time that will be spent searching for an available parking space. Additionally, the overall flow of traffic can be improved in the downtown area as a result of an API system. One of the reasons for this is that there will be a reduction in the amount of traffic that circulates in the downtown area searching for a parking space. Second, queues to enter a full parking facility should be eliminated
G-3 by directing motorists away from these full facilities to other facilities that have available spaces. Third, it can reduce the number of vehicles parked illegally and, if the system is really efficient, possibly allow for the elimination of some on-street parking (8).
The parking facilities also benefit from the use of API systems by the redistribution of parking demand from one facility to the next. This can result in a more efficient utilization in the capacity of parking in the downtown area because it uses available spaces that may have been rarely used in the past (2). While the busier parking facilities may believe that they will not benefit from the API system, there may be a solution to their concern. An API system can increase business by allowing more cars per day to use the facility and by filling the facility more efficiently at all times during the day (10).
Results From Other Countries
The systems that are utilized in other countries might differ slightly from each other, but they serve the same function. The systems that are used overseas are referred to as parking guidance and information (PGI) systems, but are similar to the API system used in St. Paul, Minnesota, which will be discussed in the next section. A few of the systems which are utilized by cities in other countries were discussed in detail in a previous paper by Keller (6). In addition, this paper (6) also provided an in-depth examination into the results of these systems on:
• Motorists’ awareness and use of PGI systems; • Parking search behavior; • Redistribution of parking demand; • Occupancy rates of parking facilities; • Amount of time spent searching for parking facilities by motorists; and • Queue lengths and delays at entrances to parking facilities.
The results that follow are only a sample of those reported by other cities in these countries which have implemented a parking and guidance information system.
Germany
• Based on a before and after study which was conducted in Aachen, reliance on the system increased with increasing distance between the home location and Aachen and decreasing frequency of visits to Aachen. The study also found that a high majority of users (81 percent) parked in the facility they had planned to use. Of these users, 46 percent had used the PGI system to reassure themselves about the availability of spaces. Of those who were not able to park in the facility of their first choice, 56 percent had used the PGI system to find their alternative location (11).
• Based on daily surveys in Frankfurt, a high percentage (80 percent) of motorists were aware of the system on any given day and 20 percent of the drivers used the system (5). It was also determined that this system was effective in reducing the amount of time spent searching for available parking spaces by motorists (4).
G-4 England
• A survey conducted in Manchester four years after implementing a PGI system indicated that only 14 percent of the motorists had followed the parking guidance signing to reach their destination. However, the survey also suggested that motorists involved in business visits to the city made three or four times as much use of the signing as others (11).
• In Kingston-upon-Thames, it was determined that only 4 percent of respondents were completely unaware of the system and 47 percent were aware of it but had not used it. Approximately 20 percent of those responded that they had used the system on the day they were interviewed (5).
Japan
• A survey of users’ opinions of the system in Toyota six months after it went into operation indicated that 71 percent of the motorists made use of the information displayed when deciding which car park to use. A high percentage of drivers (87 percent) felt that the PGI system was needed (12).
• In Yokohama, a before and after study was conducted of the PGI system. The “before” data was collected a year before the system was installed while the “after” data was collected a year after it was installed. The results indicated that on-street parking decreased 18 percent and off-street parking increased 21 percent during this time. This indicated that motorists had changed from using on-street parking to off-street parking facilities. In addition, 82 percent of motorists surveyed appreciated the useful effect of the parking information system (9).
In summary, based on the literature reviewed, the majority of motorists favor and are aware of PGI systems but only a minority use the information. The results also suggest that these systems have the greatest impact on drivers who are unfamiliar with the area and the least effect on drivers with high levels of local knowledge (11). While some of these results indicate that the benefits mentioned in the previous section (reduced parking search time and reduction in on-street parking) can be attained, more data needs to be collected in order to support and quantify these potential benefits of API systems.
G-5 API SYSTEMS IN THE UNITED STATES
While the first API systems appeared in Europe over 20 years ago, the first system in the United States did not exist until the summer of 1994. That was when Pittsburgh, Pennsylvania implemented their Wayfinder System. Since then, St. Paul, Minnesota is the only other US city to implement an API system. The reasons why these systems have not been extensively implemented in the United States will be discussed later; this section will focus on the two cities which operate systems at this time.
Pittsburgh, Pennsylvania
The downtown area of the city contains many businesses and attractions that are concentrated in a single area but are separated by the intersection of three rivers, the Allegheny, Monongahela and Ohio. This area houses Three Rivers Stadium, home of the Pittsburgh Pirates and Pittsburgh Steelers, the convention center, a civic arena, city, county and federal offices, as well as other attractions that induces vehicular traffic. Therefore, there was a challenge to implement a system that could provide information to the motorists concerning orientation to major attractions and parking facilities, as well as the availability of parking near these attractions (13).
The system that was developed is called the Wayfinder System. It consists of a “series of linked sign cues, each of which provides an ‘orientating context’ to the motorists for their journey to any of the destinations in the system (13).” This system was created to help both residents and visitors navigate from one part of the city to the other and includes both parking and pedestrian directions to major attractions (14). It divides Pittsburgh into five color-coded regions, which aid in locating the attractions within that section. The signs which are used consist of mostly static information providing guidance to both attractions and parking facilities in the different sections of the downtown area. The dynamic signs use text, such as OPEN or FULL, to describe the conditions of the parking facilities around Three Rivers Stadium. An example of both types of signs that are used in this system can be seen in Figure 1.
Figure 1. Signs Used in Pittsburgh’s Wayfinder System (13).
Although parking availability information is only provided for parking facilities located near Three Rivers Stadium at this time, it was hoped by city officials in Pittsburgh that the system could be expanded and implemented into an advanced parking information system for the entire downtown
G-6 area. However, budget constraints have led to little progress being made in this direction for the system (15).
St. Paul, Minnesota
The St. Paul API system became operational in February 1996. This system is a 12-month Minnesota Guidestar and Federal Highway Administration (FHWA) Field Operational Test Project and is supported by the Minnesota Department of Transportation (MnDOT), the City of St. Paul and the AGS Group (16). Ten parking facilities in the downtown area are included in this operational test, seven of which are privately owned (17).
The St. Paul API system was implemented because there was a perceived lack of parking in the downtown area during special events (17). These events involved the civic center, the Minnesota History Center, Ordway Music Theatre and/or the Science Museum of Minnesota, among others. These attractions bring more than 4 million people to the downtown St. Paul area. In addition, more visitors are expected with the $65 million expansion of the civic center and the relocation of the Minnesota’s Children Museum to downtown (16). Due to the large number of visitors, which consist mostly of drivers unfamiliar with the streets and parking facilities in the downtown vicinity, there was a need to efficiently guide motorists to available parking spaces (2). Therefore, the main focus of this operational test is to “demonstrate a real-time, event-based downtown parking information system for the first time in the United States (17).”
During this test, the system will only be used for event-related parking information in the downtown area. However, at its conclusion, the City of St. Paul has shown interest in keeping the system and using it for daily parking activity (2). Figure 2 shows an example of the dynamic signs that are used in the St. Paul API system.
Figure 2. St. Paul, Minnesota API Dynamic Sign (18).
G-7 RESULTS OF TELEPHONE INTERVIEWS
Interview Process and Participants
The interview process consisted of contacting city transportation, parking and planning officials and private parking facility managers by telephone. A copy of the interview forms used are located in Appendix A. A total of eighteen telephone interviews were conducted, nine with managers of private parking facilities interviews and nine with city transportation, parking and planning officials. Table 1 lists the private parking facilities whose managers were interviewed. Table 2 identifies cities whose transportation, parking and planning officials were interviewed.
Table 1. Private Parking Facilities Interviewed.
Company Location Central Parking System Birmingham, Classified Parking System Austin, Texas Ampco Parking Dallas, Texas Diversified Parking Incorporated El Paso, Texas Allright Parking Ft. Worth, Texas Central Parking System Houston, Texas Central Parking System San Antonio, Texas Safety Parking Incorporated San Antonio, Texas Milwaukee Turners Milwaukee,
Table 2. City Transportation, Parking and Planning Departments Interviewed.
Agency City Department of Traffic Engineering Birmingham, Alabama Transportation Department Austin, Texas Public Works and Transportation Department Dallas, Texas Metropolitan Planning Organization El Paso, Texas Transportation & Public Works Ft. Worth, Texas Traffic Management Division Houston, Texas Uptown Houston Association Houston, Texas Parking Division San Antonio, Texas Parking Division Milwaukee, Wisconsin
G-8 Interview Results
While most of the questions asked were the same, the first question differed to determine the number of parking facilities that were managed by the private facility managers. This question differed to determine possible bias towards later questions. The results are presented in Table 3.
Table 3. Number of Parking Facilities Managed by Parking Facility Companies.
Q: How many parking facilities are managed in downtown by your company? Number of Parking Facilities Managed Number of Responses 1 to 10 1 11 to 20 3 21 to 30 2 31 to 40 3
The first question asked of the city transportation officials was used to determine whether the private or public sector owned the majority of parking lots in the downtown area. The results of the nine responses are shown in the Table 4.
Table 4. Majority of Parking Facility Ownership in Cities Interviewed.
Q: Who owns the majority of the downtown parking facilities? Management of Parking Facilities in Downtown Number of Responses Private Majority 6 Public Majority 1 Even Split 1 Unsure 1
A majority (two-thirds) of the city officials stated that the private sector owned a majority of the parking facilities in the downtown area of their city. Based on previous discussion with transportation professionals, this was expected.
The next three questions were asked of both the private parking facility managers (PFMs) and the city transportation, parking and planning officials (COs). The second question asked concerned whether those interviewed thought that there were any problems with parking (i.e., not enough parking spaces, trouble finding spaces, complaints) in the downtown area. Table 5 presents the results of this question.
G-9 Table 5. Current Parking Problem in Downtown Area.
Q: Is there a problem with parking in downtown? Response PFMs COs Total Yes 5 4 9 No 4 5 9
Based on these results, similar proportions of both groups stated that there was a problem with parking in the downtown area. This can be expected for two reasons. One, the city officials receive the complaints from the public on parking problems in the downtown area. Two, the private parking facility managers have first-hand knowledge of how congested the parking situation is in their facility and in downtown.
If the participants stated that there was a problem with parking in the downtown area, they were asked for ways in which the problem could be improved. Their suggestions are in Table 6.
Table 6. Suggestions for Improving Downtown Parking.
Q: If there is a parking problem in the downtown area, what would your suggestions be for improvement? Suggestion PFMs COs Total Build more parking facilities 3 2 5 Provide motorists with notification of 2-2 and guidance to open parking facilities Relax parking restrictions 1 1 2 Enforce parking regulations - 1 1
Out of the 10 suggestions, it is important to note that half said building more parking facilities would solve the problem. This “build” mentality will be discussed further in the next chapter. In addition, two participants stated the need to provide motorists with notification of and guidance to parking facilities that have available spaces, something that an API system can accomplish.
The next question asked if the interviewees were aware of any advance information provided to motorists with respect to the parking situation in the downtown area. All but two of the respondents stated that they were not aware of any. Two city officials mentioned that the convention or civic center in their city either sent maps of parking facilities in the downtown area to incoming visitors who will utilize the centers or had parking maps located in the center.
G-10 After explaining an API system, the next question asked of the two groups differed. The private parking facility managers were asked if they thought their company would be in favor of such a system in the downtown area. The city officials were asked whether they thought an API system for use in downtown would be beneficial for motorists in their city. Table 7 shows their opinions.
Table 7. Opinions of API System for Downtown.
PFMs Q: Would your company be in favor an API system for downtown? COs Q: Would such a system be beneficial for motorists in downtown? Response PFMs COs Total Yes 5 4 9 No 2 2 4 Unsure 2 3 5
Stating the reasons for their preference of an API system, one of the responses was, “any guidance provided to motorists would help.” However, responses in opposition to such a system included, “such a system is not needed right now” and “this doesn’t appear that it would benefit my small company.”
Table 8 represents the positive responses to an API system for downtown traffic among the private parking facility managers. Unfortunately, since a small sample of parking facility managers was interviewed, it is difficult to accurately conclude anything based on these findings.
Table 8. Number of Positive Responses to API System Based on Parking Facility Size.
Number of Parking Facilities Number of Responses Number of Positive Managed Responses 1 to 10 1 0 11 to 20 3 2 21 to 30 2 1 31 to 40 3 2
The final question asked was to determine the concerns that each group had with API system implementation for downtown daily traffic in their city. These concerns are shown in Table 9.
G-11 Table 9. Concerns With an API System.
Q: What are some of the concerns that your company/city would have with possibly implementing an API system for downtown? Concerns PFMs COs Total Cost / Funding / Feasibility 6 5 11 System Operation 6 2 8 Cooperation 2 3 5 Effect on Motorists - 3 3
More of the private parking facility managers had concerns with the operation of the system than the city officials. Some of the questions that the respondents had with respect to the operation of the API system included:
• Who will operate the system? • Who will control the system? • Will it be utilized equally for all parties concerned? • How will the system be maintained?
The results of these surveys were used with the discussions held with transportation professionals concerning API systems to determine the challenges which exist in implementing API systems in the United States.
G-12 CHALLENGES IN IMPLEMENTING API SYSTEMS IN THE UNITED STATES
In order for API systems to be implemented successfully in major cities of the United States, the following challenges must be faced. These challenges identified below also help explain why these systems which have been so successful in other countries have not been utilized in the United States.
Cooperation Between Public and Private Sectors
Cooperation between the public and private sectors appears to be a major challenge that must be overcome in implementing an API system in the United States. Cooperation is vital because in some major metropolitan areas in the United States, private companies own a majority of the parking facilities. If the private parking facilities do not participate, then the only facilities that could be used would be the facilities that are owned by the city. However, this might not be possible. For example, in New York City, where the city owns over 60 parking facilities, they are not clustered near each other. If one of the city-owned facilities became full, there would not be a city-owned facility nearby that motorists could be directed to (19).
Private parking facility managers have a variety of reasons why they are hesitant to cooperate with the public sector. One of the reasons is that the private parking facility managers may be reluctant to share occupancy information with the government. If the government knows the occupancy and capacity of a facility, then they would know how much tax to collect from the revenues generated at these parking facilities. Since payment for parking is usually a cash transaction with no receipts, some private facility managers may have to pay the actual tax that they should have been paying previously. The reluctance of private parking facility managers to share occupancy information was one of the reasons why a proposed API system in Hartford, Connecticut was not implemented (20).
There are other concerns of the private industry with such a system. Managers of parking facilities which are full most of the time fear that some of their business will be redistributed to other parking facilities. Under an API system, motorists who usually wait in queue for a space to become available at a busy facility would be redirected to another lesser used facility that may not be owned by the same company (21). In addition, the managers of the parking facilities may not be willing to put any of their own money into an API system if they do not see any benefits from it (21).
Finally, private parking facility managers may be indifferent to the effects on traffic or motorists that parking congestion can create. If their facilities are heavily utilized, then they will be making their profit, regardless of the effects on traffic and motorists.
Therefore, for a system to succeed, it is necessary to have cooperation between the public and private sectors. The St. Paul API system, which involves seven private and three public parking facilities, can be used to show transportation professionals how partnerships can be formed. Hopefully, the results of this API system will show the private sector the benefits that can be obtained by utilizing an API system.
G-13 Cost / Funding
The cost that can be involved in the implementation of an API system along with how it will be funded are other challenges that must be conquered. The cost associated with implementing this technology can possibly prevent many cities and private parking facilities from proposing an API system. For example, the cost of the St. Paul system was $1.5 million (8). This high cost is why other agencies and private parking facilities are encouraged to join in on this system; more partners will result in more financial backing.
Another challenge that exists related to the cost is determining how the system will be funded by all of the agencies and companies involved. Should the funding of the system be the sole responsibility of one parking entity (the public side) or is it a collaborative effort by all interested parties? If it is a collaborative effort, then it must be determined how much effort and financial backing should be contributed by each entity.
However, the API system does not have to be complicated and expensive. The system that was implemented in Aachen, Germany 20 years ago used only green and red lights to indicate the availability of parking spaces (22). The total cost of the system can also be reduced by utilizing some of the technology that has already been installed for other ITS applications. If an advanced traffic management center is already in place, then the core technology that exists for the ITS infrastructure could alleviate the cost involved in installing and operating the system (2).
Creating Awareness of API System
There appears to be a lack of awareness of API systems in the United States today. A number of transportation professionals are unsure of what it exactly does, how it works and how it should be utilized (22). A good example of this was exhibited during the survey conducted for this research. All eighteen people who were interviewed in the previous chapter had never heard of an API system, and some could not fathom the idea that these systems were operating in cities in the US. In addition, the people who are in charge of the money for possible funding of an API system are not knowledgeable about such a system and, therefore, may be hesitant to fund something they have little or no knowledge about.
The motoring public is unaware of an API system simply because they have not been exposed to them. While the motorists may be aware of the parking problems that exist in the downtown area, the only solution they may know of is to create more parking spaces by building more facilities. In addition, a large number of motorists may not notice the problems created by parking in the downtown area of a city since some employers provide parking for their employees.
Therefore, the city may only get complaints from the segment of the population which does not enjoy the luxury of having a reserved space. However, if a large segment of the public complains about the lack of parking spaces, then the only option that the city may know of is to construct more parking facilities. They may not be aware that an API system is a viable alternative in alleviating the parking problems in the downtown area.
G-14 This lack of awareness of API systems can only be resolved by providing motorists and transportation officials with more knowledge of these systems. It is especially important to provide information on the two API systems which are operating in the United States at this time.
Overcoming “Build” Mentality
When comparing the United States with other countries that have API systems, the simple fact exists that the population density of many of the other countries is very high. Therefore, there is a small amount of land available to other countries in the downtown area. This severe congestion and lack of space in the downtown section of cities in other countries has “provided a strong economic incentive for technological innovation in parking management (2).”
However, when parking becomes a problem in the United States, most cities, except the larger ones, are able to build more parking facilities, thereby reducing the need to look for other alternatives. In addition, the sprawl of the land in the United States has enabled cities to create multiple centers of business and tourist attractions at different locations within the city rather than at only one location. Therefore, land is available for the city to build more parking facilities at these high demand locations (23).
In order to remedy this situation, a comparison can be drawn between parking facilities and roadways in the United States. After many years of adding lanes and building new roadways to handle the capacity on the roads in the US, it was determined that there was a limit to the number of lanes and roads that could be added to any road network. Similarly, there will come a time when the option to build more parking facilities will no longer be available. It is hoped that before this occurs, the mentality of building more facilities will be replaced by an attempt to effectively manage parking in the downtown area of the city.
Gaining Public Acceptance
A very important challenge in implementing an API system is to gain public acceptance of the system. Since the motoring public will be the users of this system and will determine how successful the system is, it is important that they accept the system. To gain public acceptance of the API system, the expense of the system must be justified and motorists' parking behavior must be altered.
In the current atmosphere of budget shortfalls at all levels of government, any expense other than which is necessary tends to be highly scrutinized by the public. Therefore, a challenge exists on the behalf of city officials to justify the expense for an API system. Justification can be accomplished by exhibiting the need for improvements to the parking situation in the downtown area (24).
In addition, the parking behavior of motorists must be changed and influenced, since motorists tend to have the ‘front door syndrome.’ They like to park as close to their destination as possible, regardless of the wait they may have to endure for an available space at the desired parking facility (24). This is a challenge because compliance with information provided by the API system is not mandatory, therefore motorists can ignore the information provided by the system and remain in queue for an available parking space (10). In order to change this behavior, the information that is presented though the API system must be credible and reliable to the motorist.
G-15 API SYSTEM IMPLEMENTATION GUIDELINES
The success which has been achieved by other countries utilizing an API (or PGI) system was not accomplished overnight. A lot of planning, discussion and bargaining had to occur before the system even became operational, much less successful. In the process of implementing an API system in the United States, a thorough process must be used to ensure that the system is implemented properly and according to the desires of those concerned.
The guidelines that follow are recommendations of the author and are based on the experiences of and recommendations by Minnesota Guidestar and the AGS Group, two agencies instrumental in implementing the St. Paul API system. In addition, the AGS Group has been involved in a handful of API systems operating outside the United States. Their experience in other countries can be applied in determining the guidelines for a successful implementation of API systems in cities across the United States for daily downtown traffic. The guidelines recommended by these agencies consisted of a list of steps necessary for implementing an API system. The author altered these steps and provided descriptions of them in producing these guidelines for implementing API systems in downtown areas of cities in the United States.
In a previous paper by Keller (6), guidelines were provided for implementing and integrating an API system with an advanced traffic management system (ATMS). However, the guidelines below are provided to enable cities to overcome the challenges which exist for implementation of API systems for daily downtown traffic. While these challenges were a basis for these guidelines, the needs of the users of the system were also considered. Since the users of the system will determine how successful an API system is, the guidelines must reflect their desires, as well as the parking facility managers. The guidelines presented below satisfy these objectives.
Stage 1: Preliminary Planning
During this stage, the development of the API system should be an evolutionary process. Once any step of the guidelines are completed, then the previous and following sets should be refined as needed. This stage of implementation will be the most important because an attempt will be made to gain support for such a system from the private parking facilities, as well as the general public who will be the users of this system.
1. Determine the Need for an API System
In determining the need for an API system, the parking problems that exist in the downtown area must be identified. Possible parking problems include a perception by motorists that there is a lack of parking spaces, an actual lack of parking spaces and/or vehicles waiting in queues to enter parking facilities. It is important during this first step that the extent to which parking is a problem in the downtown area be determined. This can be accomplished by identifying critical locations in the area where parking congestion creates problems. In addition, a study of the parking in the downtown area can be utilized in determining the extent of the parking problem. Surveys of users of the parking facilities in the downtown area can also be utilized in determining the extent of the parking problem according to the motorists who are faced with parking downtown on a daily basis.
G-16 If the public “perceives” that there is a lack of parking in the downtown area, there may be less resistance to any parking improvement, including an API system.
Once it has been determined that there is a problem with parking in the downtown area, it must be concluded that an API system is the best solution to this problem. This can be illustrated by the fact that the solution to the current parking problems can not always be solved by constructing new parking facilities. Land in the downtown area is very valuable and in most major cities, there is not very much of it available. The API system can also be considered the best solution for cities where a better parking management and information plan could be used in improving the status of parking in downtown.
2. Determine Objectives and Goals of API System
To achieve a successful implementation of an API system, the goals and objectives of the system must be decided upon. It should be determined exactly what is expected to be gained from the API system to determine the path necessary to arrive there. The remaining steps of implementation will then be based on the stated goals and objectives. In addition, it is important to link the objectives and goals of the API system with the objectives and goals of the city’s transportation system. This will enable both systems to work together to form a compatible transportation network.
The goals and objectives of the system will vary from location to location, but they should attempt to provide adequate information to motorists regarding the availability and location of parking facilities, as well as guidance to those facilities. Possible goals and objectives can resemble those for the St. Paul system which are listed below (17):
1. Create an advanced parking system that would communicate real-time parking information to users. 2. Create an advanced parking system that would serve as a way-finder system to those users unfamiliar with downtown St. Paul. 3. Develop an advanced parking system that both architecturally and aesthetically fit within the scheme of downtown St. Paul. 4. Develop an advanced parking system capable of expanding post operational testing to accommodate the City of St. Paul’s everyday traffic needs. 5. Create an advanced parking system that would have a positive impact on the surface transportation system in downtown St. Paul.
3. Get Governmental Agencies Involved - Assembling the Team Part I
The first step in assembling the API system implementation team involves getting the support of the local government agencies. In addition, it would be beneficial to include local politicians on the team. The city should at this time also attempt to determine the amount of effort and input that will be provided at the state and federal level. It would be beneficial to gain the assistance of FHWA personnel who were involved in the St. Paul project.
G-17 For those cities which have advanced traffic management centers, personnel at these locations should also be contacted in order to utilize their knowledge of ITS applications in that city. This should allow the API system to be coordinated with the existing ITS technology.
When discussing the possible implementation for an API system for daily downtown traffic for a city, it is important that the need for such a system be clearly demonstrated to every agency. By getting the governmental agencies together first, this will help in presenting the proposed API system to private industry as a proposal supported by the government at all levels. This united front will be beneficial in convincing others that a need for such a system exists.
4. Determine Participating Parking Facilities - Assembling the Team Part II
At this time, all parking facilities in the downtown area should be identified. The managers of these facilities should be contacted to provide them with background on an API system and to determine their interest in such a system. The need for an API system in the downtown area should also be demonstrated.
Involvement by the private parking facilities will be essential for the implementation of an API system in order to provide motorists with selections from a majority of the facilities in the downtown area. The lack of cooperation between private and public sectors in the past must be resolved and the benefits of cooperation should be extolled. It should be stressed that an API system will allow their facilities to be involved in an innovative effort to include parking in the ITS of the future (2). The St. Paul API system, which consists of 7 private and 3 publicly-owned parking facilities, can be used as a model for cooperation. The City of St. Paul had established a cooperative relationship with the private sector in the past and they were able to utilize this partnership for parking applications in the city (25).
In addition, any concerns that the facility managers have with an API system should be considered important and dealt with as honestly and efficiently as possible. While final solutions may not be agreed upon at this time, the issues brought forth by the parking facility managers should be taken into consideration during the entire implementation process in order to satisfy their concerns.
5. Involve Private Firms - Assembling the Team Part III
At approximately the same time as the initial contact with the private parking facility managers, it is important to finalize the API system implementation team by hiring private companies who have expertise in such systems. These companies should include those who have helped implement such systems in other locations, those with the technological background in these systems and those with experience in integrating API systems into the transportation system of the city. It is essential to utilize companies which have had success and/or have been involved in other advanced parking information systems. From the mistakes and successes of these past programs, lessons can be learned and examples provided. These private companies will join the public officials and private parking facility managers to form the API system implementation team, who will be in charge of the program.
G-18 6. Conduct Focus Groups
The focus groups should consist of the motoring public and be representative of the city population. These focus groups should be beneficial for two reasons. One, it will provide an opportunity for those on the API implementation team to expose the public to an API system and get their opinions on the system. Two, the input provided by the participants can be useful in determining the final design of the system, such as what types of signs to use and how the information would most effectively be conveyed to motorists. In addition, the participants can also provide an indication of how to develop and implement the marketing strategy for the API system. The comments and opinions provided by motorists can be taken into account before beginning the design and marketing stages, Stages 2A and 2B.
7. Identify Possible Funding Sources
Before the actual design begins in the next stage, all possible sources of funding should be identified. It is believed that a significant source of funding would either come from the state and/or federal level. This funding can be obtained using state or federal money geared for ITS applications, including Intermodal Surface Transportation Efficiency Act (ISTEA) funds provided by FHWA. However, it is not anticipated that the FHWA would provide as much funding for other projects as it did in St. Paul, where it assumed 50 percent of the budget (17). The more funding that can be obtained at the state and federal level would hopefully decrease the costs for the city and the parking facilities.
Stage 2A: Design and Pre-Installation
1. Establish Traffic Routes
In this step, the participating parking facilities in the downtown area are located and key travel routes to those facilities from different directions are identified. Once the participating parking facilities are located on a map, the downtown area should be divided into different zones based on high concentrations of people and parking activity.
The “best” route to take to a desired facility from each direction should be determined and shown on the map. This best route can either be optimized for the user or the system. User optimization provides motorists with the fastest place to park. System optimization directs motorists to facilities that will provide the most congestion relief to the downtown area (8). The overall guidance plan is complete when the routes to each individual parking facility are identified.
2. Finalize Sign Issues
Since the signs used in the API system are the most visible result of this system to the general public, two sign issues must be effectively dealt with. First, the most effective method of conveying this information to motorists should be determined. This can be ascertained from the results of the focus groups, as well by thoughts of members of the API system implementation team. The information that should be conveyed to motorists includes how the motorists will be informed of the availability and location of parking.
G-19 In displaying information regarding the availability of parking, either text or numbers can be used. Text can be used through words such as SPACES, FULL or CLOSED in describing the availability of parking in facilities in the downtown area. The numeric option simply displays the number of spaces that remain in each facility. In addition, the availability information can be manipulated to provide other indications of how full or vacant a facility is. The text/numbers can flash after a particular facility has reached a predetermined occupancy level, for example after it has reached 90 percent capacity. The text/numbers can also change colors from green to yellow to red as an indication of the number of spaces that remain. For all of these options, the API system implementation team must be sure that motorists understand the information that is displayed in the manner that it is being displayed. In addition to the availability information, the manner in which individual parking facilities are identified on the signs should also be determined. This can be accomplished by using the actual name of the individual facility, describing the major attraction the parking facility serves or by giving it a generic name.
The second issue that should be finalized for the signs used in the API system is determining where the static and dynamic signs should be placed. Static signs are usually located close to the downtown area and are used in guiding the motorists to specific parking facilities. Dynamic signs are usually placed farther away from the downtown area and are used to inform motorists on the “real-time” availability of parking. The dynamic signs should be located such that motorists are allowed enough time to utilize the availability information in determining which parking facility to use. The proper placement of the signs is determined using the routes which were established in the previous step.
3. Determine and Develop Necessary Hardware and Software
The components needed for the API system should be looked at in terms of the communication and operation equipment necessary. The decision regarding how information should be communicated between the parking facilities, the control center and the motorists should be made at this time. The options available include hard wiring, fiber optics, dedicated or leased telephone lines, modems or wireless links. The communication system that is chosen should be reliable and should not allow tampering of the information it carries. Parking facility managers should also be informed of the equipment necessary at their location as this will provide an indication of the enhancements required of their facility to become a part of the API system.
If the city has an advanced traffic management center already in place, primary consultation should occur between the center and the API implementation team. Based on what the center already uses in its communication with ITS components in place in the city, equipment should be used that interacts with the technology present. Using software and hardware that is compatible with the components of the traffic management center should reduce costs and provide the city with a more efficient API system. After the components necessary for implementation of the API system have been determined, development of needed software should begin.
4. Prepare Plans and Specifications
Detailed design plans for final implementation should be produced at this time. These documents should include the specifications for all components of the API system. For the parking
G-20 facilities, it should provide installation procedures for each individual facility, as well as the method that will be used in determining the availability of spaces at each location. For the control center, the communication system that will be used between it, the parking facilities and dynamic road signs will be specified and planned for installation. For the roadside environment, plans should be provided for installing the static and dynamic signs at new locations, as well as a traffic control plan during periods of installation.
This step should also include finalizing the cost involved in implementing the API system in the downtown area. In addition, a schedule and timetable should be established for completely installing the system.
5. Prepare Operations and Maintenance Manual
A detailed operations and maintenance manual should be prepared using input from all team members. This document should state the objectives and goals of the API system and list the responsibilities of the members of the team. A description of how the system operates should be included, as well as a maintenance and implementation schedule. Instructions on what to do if the system malfunctions should also be provided, as well as names of people to contact. This document should be continuously revised to reflect changes in operations and maintenance procedures after the system begins operation. This manual should be a comprehensive document which emphasizes every detail in the implementation and operation of the API system.
Stage 2B: Marketing Strategy
Once Stage 1 is complete, the API implementation team needs to determine the correct strategy in marketing the system to the public. Since there is a lack of knowledge of such a system among motorists in the United States, it is important that the marketing strategy developed provide both information and education of the API system.
1. Develop Marketing Plan
The marketing strategy should be prepared as a two-step process. The first step should be to identify the target market that the API system should appeal to, which will consist of those motorists who utilize the parking facilities of the downtown area. The marketing plan that will be developed should be geared towards the marketing opportunity that exists for the API system - the current lack of parking information provided to motorists.
The second step in the marketing strategy is to establish the marketing mix that should be used in communicating the API system to the motorists. It is suggested that in advertising this system, all of the general advertising mediums should be used, such as print, television, and radio. However, the inclusion of direct advertising in the form of informational sheets or brochures located at parking facilities before the system is installed will be beneficial. An example of an informational sheet that was used for the St. Paul API system can be seen in Appendix B.
G-21 2. Implement Marketing Program
After it has been decided which marketing strategies to use, the publicity campaign should begin before and after the system is operating. This step is vital in ensuring that the public is aware of the API system, its purpose and how they should respond to it.
Stage 3: Final Implementation
1. System Installation
As the first step in the last stage of implementation, the API system must be completely installed on time and under budget. It is anticipated that with a good implementation plan and partnerships between team members, this should not be a problem. The installation of the API system should coincide with the beginning of the marketing plan created in the previous stage.
2. Test the System
Before the initial start-up of the API system, the system must be tested to ensure that all aspects of it are functioning properly. This will help in determining if there any problems with the API system and enable these problems to be corrected before the system becomes fully operational. In addition, testing the system at this time ensures that motorists are provided with correct and reliable information from the start.
3. Start-up
The advanced parking information system opens for business.
4. Evaluation of System
The API system should undergo continuous evaluation to ensure that the system is meeting the stated goals and objectives. This evaluation should be done by an independent firm who was not involved in the implementation process to avoid possible bias.
5. Continuous Improvement
Based on the results of the evaluation completed in the previous step, the system should be improved upon to create a more effective API system for daily downtown traffic in the city. Improvements made to the system should be evaluated to determine their effectiveness and should be incorporated into the operations and maintenance manual.
G-22 IMPLEMENTATION GUIDELINES FOR SAN ANTONIO, TEXAS
While a case study of San Antonio was done by Keller previously for API system implementation, that study (6) was principally concerned with using an API system for special events using both downtown parking facilities and park-and-ride lots. These guidelines differ in the fact that these are recommended for daily use by motorists in the downtown area. Before the guidelines are presented, it is important to provide a little background on the City of San Antonio and its transportation system.
City of San Antonio
San Antonio, Texas is the ninth largest city in the nation and the third largest city in Texas (26). In 1990, it had a population of 935,933 people, 55.6 percent of which is of Hispanic origin (27). The city is dependent on the health care, tourism, education and military industry. There are 19 colleges and universities in the city and 5 military bases. Tourists travel to San Antonio to see the Alamo, the River Walk, El Mercado and Sea World of Texas, among other attractions (28).
TransGuide
The transportation system of the San Antonio area is controlled by their advanced traffic management center, called TransGuide, which is short for Transportation Guidance System. It was a $151 million project that was funded by the San Antonio District of the Texas Department of Transportation (TxDOT). It consists of a network of road sensors, signs, computers, cameras and people with the intent of improving the flow of traffic on the roads of San Antonio, decreasing the delays, reducing the number of accidents and providing immediate response to any incident on the roadway (29). The specifically stated system goals of TransGuide are to (26):
• Detect incidents within two minutes; • Change all affected traffic control devices within 15 seconds from alarm verification; • Allow San Antonio police to dispatch appropriate response from the Operation Center; • Assure system reliability and expendability; and • Support future ATMS and ITS activities.
With this background provided of the city and its advanced traffic management center, the guidelines for implementing an API system for downtown San Antonio will be provided. The API system will be another aspect of ITS that will enhance the transportation system of San Antonio.
Stage 1: Preliminary Planning
1. Determine the Need for an API System
The need for parking improvements in downtown San Antonio is evident based on a parking study (30) which was conducted by the Consulting Engineers Group, Inc. for the City of San Antonio. The results of this study indicated that there was a need of approximately 3500 spaces in downtown San Antonio over the next five years. This study also estimated costs for the construction
G-23 of these spaces to total $24.7 million. This estimated cost does not include land costs, development fees and permits (30).
One of the reasons for the needed parking improvements in the downtown area is that this area contains many businesses and attractions. Downtown San Antonio is a high demand location. Unfortunately, the supply of available parking facilities does not and will not appear to meet the demand. According to a previous report on API systems, factors that make a city more receptive to an API system include (6):
• Areas of concentrated activities and parking facilities, • Large number of visitors in the downtown area, • Adequate parking demand in the downtown area, • Perceived problems associated with parking, and • Congestion.
Using these factors and the estimated cost in building the necessary parking facilities, an API system appears that it would be beneficial for use by daily downtown traffic in San Antonio. Therefore, it was assumed for this paper that an API system should be installed for use in downtown San Antonio.
2. Determine Objectives and Goals of API System
The objective and goals of the API system should be related to those of the transportation system for the City of San Antonio, specifically that of TransGuide. It is important to link the goals of the API system with that of TransGuide since two of the stated goals of TransGuide are to:
• Assure system reliability and expendability • Support future ATMS and ITS activities
Aware that the API system can be integrated into the advanced traffic management center of San Antonio, the following goals and objectives of the API system were determined:
1. Provide advance information to motorists on the status of parking availability in downtown San Antonio on a daily basis. 2. Provide motorists with locational and guidance information on the parking facilities in downtown San Antonio on a daily basis. 3. Develop an API system that is highly utilized by motorists heading into downtown San Antonio. 4. Develop an API system that will efficiently utilize the available parking facilities in downtown San Antonio.
3. Get Governmental Agencies Involved - Assembling the Team Part I
The local governmental agencies should be assembled first. This should include personnel from many city offices, including the Department of Traffic, the Parking Division and the Department of Planning. Local support should also be obtained from prominent local politicians, especially the Mayor of San Antonio, the City Manager and city council members. For all of the governmental agencies, especially the politicians, the need for an API system in downtown San
G-24 Antonio should be demonstrated using reasons provided in the first step of this stage. It was assumed that these agencies from the City of San Antonio would lead this effort to implement an API system.
At the state level, the San Antonio District of TxDOT would be the main agency to contact. Since they were beneficial in the implementation and operation of TransGuide, their input is necessary for the implementation and operation of the API system for downtown San Antonio. The manager of TransGuide should also be contacted.
From the federal level, the Federal Highway Administration should be utilized to provide a national perspective on API systems. It would be advantageous for FHWA personnel who worked on the St. Paul system to be involved in the system being created in San Antonio. In addition, the City of St. Paul and the Minnesota Department of Transportation, two key participants in the St. Paul API system, should be contacted for their input on the implementation process involved in setting up an API system.
4. Determine Participating Parking Facilities - Assembling the Team Part II
All parking facilities located in the downtown area should be identified. These parking facilities should then be contacted by the city officials to determine the extent of their interest in an API system and the need for such a system should be demonstrated to them at this time. The benefits that can be obtained from the API system as well as the public/private partnership that is necessary should also be explained to each parking facility manager. For this paper, it was assumed that the thirty parking facilities listed in Appendix C would participate.
5. Involve Private Firms - Assembling the Team Part III
Private firms from San Antonio and around the world should be included in this project. Firms which have helped in the implementation of API systems in other locations should be involved as well as firms that have the technical background necessary to implement an API system should be included. In addition, those firms involved in the development of San Antonio’s advanced traffic management center should also be included.
6. Conduct Focus Groups
At this time, the focus groups will be instrumental in determining how the next stages, design and marketing, will be performed. Since there is a diverse representation of people in the San Antonio area, it is important to conduct focus groups which represent this heterogeneity and involve the large Hispanic population of San Antonio. Persons selected to participate in the focus groups should be randomly chosen from a pool of citizens who have driver’s licenses.
It is anticipated that a number of focus groups will be used during this process. Focus groups should be informal with a small number of participants to allow for comfortable discussion. The opinions of the participants should be taken into account in determining the final design of the system, such as what types of signs to use and how the information would effectively be conveyed to the motorists. These focus groups should help the city determine the current awareness of citizens
G-25 of an API system in order to determine the extent of the marketing campaign that needs to be undertaken in San Antonio. In addition, any recommendations or concerns brought forth by the participants should be considered by implementation team members.
7. Identify Possible Funding Sources
The funding that will be received from any entity is undetermined at this time. It is hypothesized that most of the cost of such a system will be incurred by the City of San Antonio, TxDOT and FHWA. It is anticipated that ISTEA and/or ITS funding could be used to implement the API system for downtown San Antonio. An additional source of funding can come from the taxes that are placed on the revenues of the downtown parking facilities. This would allow money that is obtained from parking in downtown San Antonio to be put back into the API system for downtown San Antonio.
Stage 2A: Design and Pre-Installation
1. Establish Traffic Routes
After the participating parking facilities have been identified, those parking facilities should be located on a map of the downtown area. The participating parking facilities, which are listed in Appendix C, are identified on the map in Figure 3 on the next page.
Knowing the locations of the participating parking facilities, downtown San Antonio should be divided into different zones based on high concentrations of people and parking activity. The zones which were developed for downtown San Antonio are listed below and can be seen in Figure 3 as well:
• North (Apartments, Hotels, Theaters, Museums) • West (Civic Center, City and County Offices, El Mercado) • Central (Banks, Offices, Mall, River Walk) • South Central (Convention Center, Federal Buildings, Hemisfair Park) • East (Alamodome, Historic Buildings, Hotels)
Each zone should be distinguished from the other on the roadway by color-coordinating the signs to represent a particular zone. The names for the zones were developed to provide easier identification of where a parking facility is with respect to the layout of downtown San Antonio.
After the zones are determined, approaches to each individual parking facility from each direction are identified in identifying the routes motorists must take to reach that particular parking facility. The best route for the motorist to take should be identified from each approach. An example of how this was accomplished for parking facility 10 can be seen in Figure 4. After this has been accomplished for each participating parking facility in downtown San Antonio, the overall guidance plan will be established.
G-26 * Number in circle indicates publicly owned parking facility * Letter in square indicates privately owned parking facility
Figure 3. Map of Participating Parking Facilities and Zones of San Antonio API System.
G-27 Figure 4. Approach Routes and Location of Static Signs for Parking Facility 10.
2. Finalize Sign Issues
The issues that should be determined during this step are the location of the static and dynamic signs, the type of dynamic signs to use and the identification of parking facilities on the signs. First, using the traffic routes that were established for each facility in the previous step, the static signs for each parking facility should be located at key decision points within the zone. This was accomplished for parking facility 10 discussed previously. The locations of the static signing for this facility can be seen by the dark Xs in Figure 4.
The first set of dynamic signs should be located along key routes outside the zones of downtown San Antonio. This set of dynamic signs should provide availability information for the entire zone. As the motorists approach a certain zone in downtown San Antonio, dynamic signs
G-28 should be located immediately outside the zone to indicate the availability of parking within that particular zone. The darkened squares in Figure 5 represent the locations of the dynamic signs for use in the downtown San Antonio API system.
Figure 5. Location of Dynamic Signs for San Antonio API System.
G-29 Since there was no indication of whether descriptive or numeric text was better understood by motorists while conducting this research, it is suggested that this decision be made by the San Antonio API system implementation team. The results of the focus groups should definitely be used in deciding which type of text to use. While the St. Paul system used actual facility names for identifying the parking facilities, it is recommended that a generic name be used in identifying the parking facilities. These names should consist of a letter first to indicate which zone the parking facility is located in and then should include a general number. For example, parking facility 10 which has been looked at previously, should be labeled SC-10 on the signs to indicate that it is in the South Central zone of downtown San Antonio (31). This should be beneficial since motorists are not always certain where some businesses or attractions are, they may just know the section of the city that they are located in.
3. Determine and Develop Necessary Hardware and Software
The exact components necessary for implementing an API system in San Antonio is beyond the scope of this research. However, it is anticipated that technology that is used by TransGuide would be applied to an API system in downtown San Antonio. In addition, if any software is needed to be developed, TransGuide has a software development and testing platform that it uses to allow for development and enhancement of technologies within the transportation system of San Antonio (26).
4. Prepare Plans and Specifications
The plans and specifications required for the installation and operation of the system must be developed at this time. Since all the details are known about the components of the system, these documents should explain the final installation process. Detailed design requirements and specifications should be drawn up for the entire system.
It is beyond the scope of this paper to determine a budget or timetable for implementation. This process should be undertaken by the city agencies and other members of the San Antonio API Implementation team.
5. Prepare Operations and Maintenance Manual
Using the plans and specifications created above, the Operations and Maintenance Manual for the San Antonio API system must be developed. This should be developed based on recommendations from the API system implementation team, as well as any information that is provided by the operations and maintenance staff of the city. This should describe the responsibilities of all the team members and a description of what they are expected to do after the San Antonio API system becomes operational. This manual should also provide an in-depth description of how the system works, i.e. getting the communication from the parking facilities to the drivers. This document should have implementation and maintenance schedules, as well as a section detailing what should be done in cases in which the system is malfunctioning. Revisions and additions should be made to this document as they become necessary.
G-30 Stage 2B: Marketing Strategy
1. Develop Marketing Plan
The marketing plan should target those motorists heading into downtown San Antonio. This target audience will consist of a diverse selection of people. Therefore, the marketing plan should be aimed at every segment of the population in San Antonio. Most importantly, though, since San Antonio has a large Hispanic population, it is important that this segment of the population be taken into account.
The marketing mix should principally include informational sheets or brochures that can be placed at individual parking facilities. An informational sheet similar to the one in Appendix B that was utilized in St. Paul should be developed. It is recommended that the informational sheets be placed on the windshield of the vehicles in the parking facilities a couple of times in the month before the system is installed to increase awareness of the system. During and after this time, these brochures or informational sheets can be located in the parking facilities. Advertisements could also be placed in two of the city’s newspapers. These ads should inform the public of the forthcoming API system for downtown San Antonio and explain how they should respond to the system. The papers that should be utilized include the San Antonio Express-News, San Antonio’s largest daily newspaper and La Prensa, San Antonio’s bilingual newspaper.
While the marketing plan should include the use of television and radio, it is suggested that these be minimally used. An effective 30 second spot should be developed and provided to local television stations for their use as a public service message. The radio is limited in its effects of showing the system to the public, but a description of how to react to these signs can be included. It is suggested that the radio advertisements that are developed run during the rush hours, especially after the traffic reports that most radio stations provide.
The public information campaign should include all of these methods before and after the system is implemented to ensure that a majority of motorists who use the downtown area are aware of the system and its potential benefits. This marketing plan should include a “media kick-off” event where the media is invited and team members present and discuss the API system. This was successfully accomplished for the start-up of the St. Paul API system (25).
2. Implement Marketing Program
The marketing program should be implemented several weeks before the API system begins operation. Continued advertising should also occur after the initial start-up to reinforce the San Antonio API system.
Stage 3: Final Implementation
1. System Installation
The API system for the downtown area should be completely installed on time and under budget.
G-31 2. Test the System
Before the system becomes fully operational for use by daily downtown traffic in San Antonio, it is suggested that all aspects of the system be tested. This includes making sure all the electronic variable message signs are functioning, but most importantly that the availability of each parking facility is being correctly tabulated. The number of spaces which remain should not be shown on the signs at this time, as the motorists might think they are operational. Those signs should be turned off during this test and the availability information can only be shown on the computers in TransGuide.
3. Start-up
The San Antonio API system should open for business. This date, once it has been confirmed, could be displayed on the dynamic signs before the system becomes operational. Therefore, these signs will inform the motorists of when the API system will become functional. In addition, extensive media coverage of the first day of operation would be beneficial to get more publicity about the system.
4. Evaluation of System
The evaluation of the system should be done by an independent firm who was not involved with the implementation process. This will allow an unbiased evaluation on the degree of success of the system. The independent firm should be knowledgeable with the stated objectives and goals of the system as a measuring stick to determine the performance of the system. Quantifying the potential benefits of this system (parking redistribution, reduction in parking queues, reduction in illegal and on-street parking) as well as surveying motorists in the downtown area are other options that should be explored in determining the effectiveness of the San Antonio API system.
5. Continuous Improvement
Using the results of the independent evaluation firm, members of the API implementation team should gather and focus on providing recommendations for improving the system.
The implementation guidelines presented above for an API system for daily downtown traffic in San Antonio are the views of the author. These guidelines do not officially represent the views of the City of San Antonio, the Texas Department of Transportation or other government agencies and companies mentioned throughout this report, including their employees. However, it is hoped that when solutions to the parking problem in downtown San Antonio are being sought that the alternative of using an advanced parking information system be an option that is examined. It is hoped that these guidelines, or parts of them, presented above can become a blueprint for API system implementation in San Antonio.
G-32 CONCLUSIONS
The results of this research indicate that API systems can be installed and utilized in the United States if the proper steps are taken during the planning and implementation stages. In addition, the St. Paul system provides evidence that the challenges which exist in implementing an API system can be overcome. While it is hoped that API systems become more operational in the United States, it is apparent that there are many issues and concerns that must be addressed before a system is implemented.
In cities where the perceived supply of parking in the downtown area does not meet the demand, API systems appear to be an effective means of efficiently utilizing parking facilities in the downtown area. In addition, these systems appear that they would be highly utilized in downtown locations where there are many attractions in addition to office buildings. However, since 85 percent of American commuters have a reserved parking space at their place of employment (32), it is believed that an API system would not be effective solely for the use of commuter traffic.
Finally, not enough information has been provided to transportation professionals and the motoring public in the United States on API systems. It is hoped that the results of the two API systems operating in the US are documented and provided to transportation professionals around the country.
RECOMMENDATIONS
Recommendations for implementing API systems for daily downtown traffic in cities in the United States were presented in the guidelines. However, it is reiterated here that every attempt should be made by cities interested in API systems to overcome these challenges in implementing the system.
It is recommended that the St. Paul API system and implementation plan be a model for future systems in the United States. Although the results of this system have yet to be determined, the author believes that the steps taken to implement this system in St. Paul will result in a successful API system.
It is also recommended that the benefits gained by using API systems be quantified. This would provide concrete evidence on the advantages of the system when attempting to gain support for it, especially among the managers of the parking facilities and the motoring public.
G-33 ACKNOWLEDGMENTS
The author would first like to thank God for providing me with my life and for the support He has given me.
The author also is thankful for all of the mentors who participated in this program. This includes: Walt Dunn, Ginger Gherardi, Les Jacobson, Jack Kay, Colin Rayman and Thomas Werner. Their willingness to spend their own time with future transportation professionals is greatly appreciated. A special thanks is extended to Les Jacobson for his guidance as my mentor through this research. Thanks is also extended to Dr. Conrad Dudek, who has put together an exceptional course and has been an effective leader of the Advanced Institute program. Thanks also go to Sandra Mantey for helping with the little details of this course and the program.
In addition, thanks go out to the individuals who participated in my telephone interview. Gratitude is also expressed to the following transportation professionals who were helpful in providing me with information for this report:
• Samuel Boyd - Minnesota Department of Transportation • Joe Cannisi - New York City Department of Transportation • Richard Golber - AGS Group • Marc Hustad - HNTB • Ken Johnson - San Antonio Parking Division • Bridgette Keller - Kimley-Horn • Walter Kraft - PB Farradyne, Inc. • Jim Kranig - SRF • Chris Luz - HNTB • Dick McCasland - Texas Transportation Institute • Bhupen Patel - City of Hartford Transportation Department • Gary Rylander - Edwards & Kelcey • Joel Stahl - Metropolitan Trade Association of Parking Garages for New York City
A final word of thanks is also extended to Kelli Dosch, who was instrumental in looking over and editing my report.
G-34 REFERENCES
1. National Program Plan for Intelligent Vehicle-Highway Systems, Volume I. U.S. Department of Transportation, May 1994.
2. Orski, C. Kenneth. “Electronic Parking Information Systems.” In Parking, June 1996, pp.31- 33.
3. Booklet entitled “Installing Your Parking Guidance System” published by Dambach-Werke GMBH, United Kingdom.
4. Axhausen, K.W., J.W. Polak and M. Boltze. “Effectiveness of Parking Guidance and Information Systems: Recent Evidence from Nottingham and Frankfurt am Main.” In ITE 1993 Compendium of Technical Papers, pp.109-113.
5. Polak, J.W. and K.W. Axhausen. “Measuring the Effectiveness of Parking Guidance Systems: A Case Study of Frankfurt/Main.” Proceedings of the International Conference on Advanced Technologies in Transportation and Traffic Management. Singapore, May 1994.
6. Keller, B. “Integrating Advanced Parking Information Systems With Traffic Management Systems.” In Graduate Student Papers on Advanced Surface Transportation Systems. August 1995.
7. Asakura, Yasuo and Masuo Kashiwadani. “Effects of Parking Availability Information on System Performance: A Simulation Model Approach.” 1994 Vehicle Navigation & Information Systems Conference Proceedings. Yokohoma, Japan, August 31-September 2, 1994.
8. Presentation notes on API Systems given by Mr. Walter Kraft, Senior Vice President, Farradyne Systems, Inc.
9. Kawano, I. “Parking Navigation System for Yokohama Station Area.” Towards an Intelligent Transport System: Proceedings of the First World Congress on Applications of Transport Telematics and Intelligent Vehicle-Highway Systems, Paris, France, 1994.
10. Allen, Philip A. “Driver Response to Parking Guidance and Information Systems.” In Traffic Engineering & Control, Volume 34, Number 6, June 1993, pp.302-307.
11. Polak, John W., Ian C. Hilton, Kay W. Axhausen and William Young. “Parking Guidance and Information Systems: Performance and Capability.” In Traffic Engineering & Control, Volume 31, Number 10, October 1990, pp. 519-524.
12. “Smart Parking in Toyota’s Downtown.” In ITS International, Issue Number 4, March 1996, pp. 89-90.
G-35 13. A New Intelligent Transportation Device: A Sign. Linked-Orienting-Context Wayfinder Sign System. Informing Design, Inc. and the AGS Group.
14. Internet Services Corporation, “Pittsburgh Area Ground Transportation,” [http: //www. pittsburgh.net/sites/pghnet/Visiting/Visiting.html], 1996.
15. Telephone discussion with Mr. Richard Golber of the AGS Group concerning API systems in the world.
16. “Managing Events in St. Paul.” In ITS International, Issue Number 4, March 1996, p. 88.
17. Boyd, Samuel J. and Gary F. Rylander. “Advanced Parking Information System - Operational Test.”
18. Brochure entitled Minnesota Guidestar Advanced Parking published by the Minnesota Department of Transportation’s Advanced Transportation Systems Office.
19. Telephone interview with Mr. Joe Cannisi of the New York City Parking Division concerning parking in the New York area.
20. Telephone interview with Mr. Bhupen Patel, Transportation Chief for City of Hartford, discussing Hartford’s attempt at implementing an API system.
21. Telephone interview with Mr. Joel Stahl, Director - Metropolitan Trade Association of Parking Garages, New York, concerning API systems.
22. Telephone interview with Walter Kraft of Farradyne Systems, Inc. discussing API systems.
23. Telephone interview with Jim Kranig of SRF discussing API systems.
24. Booklet entitled “Electronic Signing & Parking Management” published by the AGS Group.
25. Telephone conversation with Samuel Boyd of the Minnesota Department of Transportation discussing the St. Paul API system.
26. Booklet entitled TransGuide: Technology in Motion published by the San Antonio District of TxDOT.
27. Parker, N., D. Merrill and C. Stuber. “1990 US Census Data: San Antonio city,” [http://venus. census.gov/cdrom/lookup], 1996.
28. Cain’s Services. “San Antonio General Information,” [http://www.cains.com/sa/general. htm#RTFToC14], 1996.
29. Pamphlet entitled TransGuide: Technology in Motion published by the San Antonio District of TxDOT.
G-36 30. Downtown San Antonio Parking Study. Completed for the City of San Antonio Parking Division by the Consulting Engineers Group, Inc. October 1995.
31. Recommendation of Walter Dunn during presentation on 3 August 1996.
32. Langdon, P. A Better Place to Live: Reshaping the American Suburbs. University of Massachusetts Press, Amherst, Massachusetts, 1994.
G-37 APPENDIX A Sample Telephone Interview Forms
Interview of Private Parking Facility Managers Name: Position: Company:
1) How many parking facilities are managed in downtown by your company?
2) Is there a problem with parking in downtown?
3) If there is a parking problem in the downtown area, what would your suggestions be for improvement?
4) Are you aware of any information currently provided to motorists to inform them of the parking conditions in the downtown area?
Explain advanced parking information systems at this time.
5) Would your company be in favor of an API for downtown (city)? Why or Why Not?
6) What are some of the concerns that your company would have with possibly implementing an API system for downtown?
Interview of City Transportation, Parking and Planning Officials Name: Position: City:
1) Who owns the majority of the downtown parking facilities?
2) Is there a problem with parking in downtown?
3) If there is a parking problem in the downtown area, what would your suggestions be for improvement?
4) Are you aware of any information currently provided to motorists to inform them of the parking conditions in the downtown area?
Explain API systems at this time.
5) Would such a system be beneficial for motorists in downtown? Why/Why Not?
6) What are some of the concerns that your city would have with possibly implementing an API system for downtown?
G-38 APPENDIX B Example of St. Paul, Minnesota’s Marketing Campaign
G-39 APPENDIX C Participating Parking Facilities in San Antonio API System
Public Facilities (20) Private Facilities (10) 1. Basila Lot A. Allright SA Parking Incorporated 110 N. Laredo 405 N. Saint Mary’s St 2. Center Street Lot B. Ampco Auto Parks Incorporated 243 N. Center St 112 E. Pecan St 3. Central Library Garage C. Central Parking System 600 Soledad 404 Navarro St 4. Commerce Lot D. Central Parking System Commerce @ Soledad 110 Losoya St 5. Continental Lot E. Classified Parking Systems Incorporated 118 S. Laredo 217 W. Travis St 6. Crockett Lot F. NBC-Bank Parking Cherry @ Crockett 116 E. Martin St 7. Dolorosa Lot G. One Riverwalk Parking Garage Dolorosa @ Santa Rosa 700 N. Saint Marys St 8. Durango North H. Rand Parking Garage 727 E. Durango 122 N. Main Ave 9. Durango South I. RiverCenter Garage 700 E. Durango RiverCenter Mall 10. Hemisfair Garage J. Safety Parking Incorporated 600 E. Market 318 W. Houston St 11. Houston / Cameron Lot Houston @ Cameron 12. Houston / Nolan Lot Houston @ Elm 13. IH-35 Lots Martin to Guadalupe 14. Marina Garage 850 E. Commerce 15. Market Square Lot 612 W. Commerce 16. Mid-City Garage 240 E. Houston 17. Riverbend Garage 210 N. Presa 18. RSF Lot Rossy @ Salinas 19. San Fernando Lot 400 W. Travis 20. Sutton Lots Cherry @ Center Street
G-40 Kelly D. Parma received his B.S. in Civil Engineering from Texas A&M University in December 1995. Kelly is currently pursuing his M.S. in Civil Engineering from Texas A&M University. Kelly has been employed by the Texas Transportation Institute since June 1992 and has worked as a Graduate Research Assistant since January 1996. University activities he has been involved in included: Institute of Transportation Engineers, American Society of Civil Engineers and Chi Epsilon. His areas of interests include: transportation operations and traffic management.
G-41 EXAMINATION OF A UNIFORM SMART CARD FOR ELECTRONIC TOLL COLLECTION AND TRANSIT FEES
by
Clint Schuckel
Professional Mentor Colin A. Rayman, P.E. Ontario Ministry of Transportation
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas
August 1996 SUMMARY
Developments in technology are rapidly creating a “cashless society” in which the transfer of funds as payment for goods and services occurs electronically without conventional cash and coin changing hands. People are growing accustomed to making everyday transactions with magnetic stripe bank cards, credit cards and phone cards. High speed transactions also may occur through radio frequency identification (RFID), a common method of collecting tolls on freeways. The development of computer chip technology and reduction in manufacturing costs has created a new medium for electronic transactions: smart cards. Smart cards have potential applications in transportation due to the high number of low value transactions processed and the desire to increase person throughput. The card is a small computer, with a microprocessor and memory, which allows it to be used for many applications with independent or shared files on the card. The objective of this paper is to explore the possibility of implementing smart cards in transit agencies and toll road operations. The concept of an integrated payment system in which a smart card can be used to pay either transit fare or tolls is developed. Information for this paper was provided by an extensive literature review and phone interviews with transit authorities, toll road operators, and industry experts.
The initial assumption of this work was that the integrated payment system concept will be realized in the future through RFID and smart card technology. To determine the technical challenges in smart card implementation, a state-of-the-art review was conducted to define the basic components of vehicle transponders in toll collection and smart cards in transit. This task was performed to define the basic design differences which result in incompatibility among systems. The European ADEPT and GAUDI projects, which tested smart card-based transponders are reviewed. Four smart card applications in U.S. transit systems, at various stages of development are described. To gain insight into smart card applications in the toll road industry, three U.S. toll systems are presented in this paper. The associated smart card issues were classified into technical, economic and institutional categories for transit and toll systems, respectively. The next task was to apply the discussion to a hypothetical case study in order to examine the options available to an agency wishing to pursue smart card implementation. Three alternatives were developed for a hypothetical case study in Houston, Texas.
The results of this research indicate that an integrated payment system is possible through the development of a smart card-based transponder. Transit agencies may receive many immediate benefits from smart cards, including increased passenger throughput and reduced transaction processing costs. Toll operators currently using the conventional RFID tags, however, will not likely receive these benefits due to the efficiency of the centralized accounting system and satisfaction with the current equipment. Smart cards would create a decentralized accounting system, which has yet to be proven as cost-effective alternative to the current operation. Therefore, smart card development in transit is expected to occur at an accelerated rate in the near future, with limited activity expected in toll collection. Consumer demand, cost-effectiveness of decentralized accounting, and commercial vehicle operations are identified as three factors which will influence smart card development in toll collection. This paper concludes by making recommendations concerning the technical specifications, economic conditions, and institutional requirements that should be met for a successful integrated payment system.
H-ii TABLE OF CONTENTS
INTRODUCTION ...... H-1 Objectives ...... H-1 Scope ...... H-2 Organization of Report ...... H-2
TECHNICAL OVERVIEW AND EUROPEAN CASE STUDIES ...... H-4 Interoperability Among Radio Frequency/Microwave Systems ...... H-4 Transponder Design ...... H-4 Signal Parameters ...... H-6 Smart Cards ...... H-7 Contact Cards ...... H-8 Contactless Cards ...... H-8 Hybrid Cards ...... H-9 European AFC and ETC Projects ...... H-9 ADEPT ...... H-9 GAUDI ...... H-11
SMART CARDS IN AUTOMATED FARE COLLECTION (AFC) ...... H-13 Selected Proximity Smart Card Projects in U.S. Transit Systems ...... H-13 Chicago ...... H-13 Seattle ...... H-14 Ventura County, California ...... H-15 Washington, DC ...... H-16 Summary ...... H-16 Technical Issues ...... H-16 Standards ...... H-16 Card Features ...... H-17 Economic Issues ...... H-18 Card Cost ...... H-18 Infrastructure Cost ...... H-19 Institutional Issues ...... H-19 Closed Systems ...... H-19 Open Systems ...... H-20 Regulation E ...... H-20
SMART CARDS IN ELECTRONIC TOLL COLLECTION (ETC) ...... H-21 Selected U.S. ETC Facilities ...... H-21 California FasTrak ...... H-21 Illinois I-Pass ...... H-22 Virginia FasToll ...... H-23 Summary ...... H-23
H-iii Technical Issues ...... H-24 Standards ...... H-24 Active and Semi-Active Transponders ...... H-24 Automatic Replenishment ...... H-25 Driver Distraction ...... H-25 Economic Issues ...... H-25 Transponder Cost ...... H-25 Decentralized Accounting ...... H-26 Institutional Issues ...... H-26 Agency and Customer Satisfaction ...... H-26 Preferred Accounting System ...... H-26 Interagency Groups ...... H-27
CASE STUDY: SMART CARD IMPLEMENTATION IN HOUSTON, TEXAS .... H-28 Alternative 1: METRO Operates ...... H-28 Alternative 2: Private Contractor Operates ...... H-29 Alternative 3: Acceptance of Bank/Credit Cards ...... H-29 Comparison of Alternatives ...... H-30
CONCLUSIONS ...... H-31 Motivation to Implement Smart Card Systems ...... H-31 Benefits of an Integrated Payment System to Other Modes ...... H-32
RECOMMENDATIONS ...... H-33 Technical Specifications ...... H-33 Economic Justification ...... H-34 Institutional Requirements ...... H-35
ACKNOWLEDGMENTS ...... H-36
REFERENCES ...... H-37
H-iv INTRODUCTION
The electronic transfer of funds is rapidly replacing the need for paper and coin currency transactions in all facets of daily life. From direct-deposit paychecks in the banking industry to credit card purchases via the Internet, the need for cash to make routine purchases and payment for services is steadily declining. The transportation industry is on a similar course toward the eventual elimination of cash and tokens as payment for services. Two primary examples of this trend are identified as Automated Fare Collection (AFC) in the transit industry and Electronic Toll Collection (ETC) in the tollroad industry. Magnetic tickets were the first AFC technology in the United States, appearing nearly 30 years ago in the Chicago transit system (1), while the first ETC facilities in this country became operational in the early 1990s (2). Significant advantages of these systems included increased throughput capacity, customer convenience, and reduced cash and coin handling on the part of the service provider.
Radio frequency identification (RFID) has become the predominant communication device for ETC due to its superior ability to (1) transmit data at a high rate, increasing transaction accuracy, (2) transmit data at relatively large distances, allowing high vehicle speeds, and (3) operate within harsh environments (3). RFID is also used in the newest generation of fare media in transit- smart cards. The first major application of smart cards occurred in the French telephone industry in the mid 1980s (1). Since this time, several European and Asian countries have developed transit fare and toll collection systems using smart cards, while several U.S. metropolitan transit agencies have just begun the testing and implementation phase. Smart cards are a realization of a concept known as the “electronic purse.” The electronic purse is defined as a “payment medium in an electronic format which contains real purchasing power for which the customer has paid for in advance.” (4) Smart cards have the processing and memory storage capabilities to create an integrated payment system. An integrated payment (IP) system is defined as a uniform payment medium which is accepted by all components of a transportation system (car, bus, rail, ferry). This paper investigates the various challenges to implementing an integrated payment system among AFC for transit and ETC for tollroads. As the public warms to the smart card and electronic purse concept, there is little doubt that smart cards will become the preferred method of payment for all goods and services, including those provided by the transportation sector.
Objectives
The primary purpose of this paper was to analyze the feasibility of a smart cart IP system for transit and toll collection. The specific objectives of this research were to:
1. provide a basic understanding of the transponder and smart card by discussing the basic design differences which result in incompatible systems;
2. describe several transit and toll smart card applications in Europe and the United States either in the operational, early implementation, or planning stages;
3. determine the technical, economic and institutional issues regarding the development of smart cards in transit (AFC) and on toll facilities (ETC);
H-1 4. apply the research findings to a hypothetical case study in Houston, Texas;
5. summarize the benefits of a smart card IP system to transit and toll authorities, and;
6. develop recommendations regarding the necessary technical, economic and institutional requirements for implementing a smart card IP system for AFC and ETC.
Scope
This paper examined the development of smart card systems for AFC and ETC in the United States. Other advanced revenue collection systems such as magnetic stripe, optical systems, and bar code systems exist, however, the issues associated with these systems are beyond the scope of this paper. The assumption made here was that both RFID and contactless smart cards represent the future payment media used by a transit/toll IP system. Examination of the legal, privacy and security issues are beyond the scope of this analysis. The focus is on the transponder and smart card itself, and not on the issues associated with other components of AFC or ETC systems. The smart card and toll projects reviewed were selected as examples of the developing technology, and do not represent an exhaustive list of activities. An extensive literature review and phone interviews with selected ETC and smart card vendors, transit agencies, and industry experts provided information for this paper. Organization of Report
To provide a basic technical understanding of the integrated payment system proposed above, an overview of RFID and smart cards is found in the first proceeding section. The objective was to define the pertinent ETC and AFC terminology, and the design differences which are barriers to interoperability. A description of transponder types, RF signal parameters, and smart card configurations is included. The first section concludes with an overview of the ADEPT and GAUDI projects in Europe, which are testing smart cards for various transportation applications.
The second section contains an overview of the current smart card implementation schemes in the Chicago, Seattle, Ventura County (California), and Washington, DC transit systems. The basic scope of each project, future objectives, and system implementation are described. The technical, economic and institutional issues concerning a multi-agency smart card payment system for transit services are also discussed in the second section.
The third section of this report includes a description of the development of smart card-based transponders for ETC. Although transponders currently in operation on U.S. tollroads do not incorporate a smart card, the technology is available for product deployment. Virginia FasToll, Illinois I-Pass, and California FasTrak, represent ETC systems which have applied among the most advanced transponder technologies found in the United States. Finally, the technical, economic and institutional issues resulting from smart card implementation in ETC are discussed to conclude the third section. A hypothetical situation is introduced in the fourth section in which the transit and toll agencies in Houston, Texas wish to develop alternatives for smart card development. Since the technology has not yet been tested in Houston, this will offer an opportunity to summarize the necessary steps that agencies must take to achieve an IP system.
H-2 The conclusions drawn from this research are presented as well as a summary of the immediate effects and potential benefits that may be realized from the introduction of smart cards in transit and toll collection. Also in the fifth section, the potential advantages of an integrated payment system which includes other transportation modes such as rail, taxi and parking are introduced.
In the final section, recommendations regarding the implementation a smart card IP system for AFC and ETC are made. The technical, economic, and institutional requirements that must be met before successful introduction of the system are presented to conclude this paper.
H-3 TECHNICAL OVERVIEW AND EUROPEAN CASE STUDIES
In an IP system, where a smart card is used to pay transit fare and tolls, the vehicle-based transponder must accommodate the person-based features of a wallet sized credit card (5). Currently there are few standards for ETC systems which have resulted in a variety of configurations and communication methods. To address the IP-smart card concept, it is necessary to first review the various technologies employed and discuss basic advantages and disadvantages of the components. This will provide a basis for the discussion which follows in subsequent sections. Included in this section is a description of the various types of RF transponders and signal parameters for communication between the transponder and transceiver. The types of smart cards available and a similar description of the signal parameters for communication between the card and reader follows. A discussion of the transceiver, card reader, and the central computer system which processes the account data is beyond the scope of this paper. This section concludes with an overview of European IP-smart card projects which offer insight to potential development in North America.
Interoperability Among Radio Frequency/Microwave Systems
Radio frequency identification (RFID) occurs through a series of messages sent between an antenna, or transceiver, and the vehicle tag, or transponder. The messages are sent via electromagnetic radiation in the radio and microwave frequency range of 500 MHZ to 40 GHz. The difference between RFID and microwave communication is essentially the signal frequency only, and thus, the terms are often used interchangeably in reference to ETC (2). The process in which the transceiver signals the transponder, receives the account number from the vehicle, and identifies the tag in a computer database is known in the industry as a ‘handshake.’ Due to a lack of ETC standards, the transponder and the communication signal differ among manufacturers, and therefore tags in one system cannot be read by another (6). The concept of interoperability refers to the condition where tags and readers in different toll systems can communicate with each other, regardless of location, or manufacturer (7). Nationwide interoperability implies that a vehicle tag can be used to pay tolls at any ETC system in the U.S. Interoperability can occur at the tag level, if tags are able to recognize different readers, or at the reader level if readers are able to recognize different tags (7). Tag level interoperability is currently not feasible due to variations in transponder design and signal parameters among manufacturers.
Transponder Design
Transponders are classified based on their ability to receive and store information about the transaction and on their source of power (2,6). A transponder’s ability to record information about the transaction is known as read/write capability and a tag without this capability is referred to as a read-only tag. Read/write capability is used in “closed” toll systems. In this case, the toll is based on the distance traveled on the facility, and the date, time, and location are written into the tag’s memory for later identification at the exit point. A transponder lacking its own power source is known as a passive device, while an active tag relies on batteries, or the vehicle for power. The passive tag simply reflects the interrogation signal while the active tag responds to the signal by broadcasting the account information. Semi-active tags have an internal lithium battery which powers the broadcast when switched on by a signal from the transceiver. Semi-active tags offer a
H-4 balance between the active and passive configuration (2,6). Table 1 summarizes the classification of transponders, including the advantages and disadvantages of each type.
Table 1. Summary of Transponder Types (2,3).
Class Communication Advantages Disadvantages
Type I Read-only C Low cost, long life expectancy C May not work well in closed toll C Works well in open toll systems systems C No driver interface
Type II Read/write C Low cost C May have rigid or limited data structure C Works well in closed toll systems C May provide real-time information C No driver interface for traffic management
Type Read/write with C Highest data security C High cost III driver interface C Potential for multiple applications C May cause distraction to driver C Can be used to provide traffic C Decentralized accounting system may information to the driver not be desirable
Type Power Source Advantages Disadvantages
Passive Transceiver C Does not require a power source C Must have proper orientation to reflect C Cheaper unit cost signal C Reduced lane-to-lane interference C Greater susceptibility to noise interference due to lower signal strength
Active Vehicle or C Return signal stronger; reduced C Lane-to-lane interference increased batteries interference from other systems C Higher cost, more complex circuitry C Can communicate at any C Reduced battery life orientation
Type I transponders, the cheapest and simplest technology, are optimal for open toll systems which charge a fixed fee for entry (2,6). Open systems are commonly bridges, tunnels or highways charging a fixed rate. ETC systems using Type II tags generally are used on tollroads which charge based on the distance the vehicle travels. Type III transponders are the only group which have the memory storage and processing power required to maintain separate accounts within the tag itself. These devices actually store monetary value whereas the account balance resides in the agency database in other designs. However, the agency may need to keep track of certain account information to prevent fraud, resolve transaction disputes, and/or for traffic management purposes. Type III’s can be configured to accept a smart card similar to the manner in which a diskette is inserted into a computer. The added features of the Type III, including batteries, lights, and a liquid crystal display (LCD) make the device larger in size than other designs. Current U.S. Type III’s have yet to integrate a smart card to store the account balance, but several smart card transponders are in use worldwide. Type III transponders are also desirable due to their ability to provide drivers with real-time traffic information, along with feedback on toll charges and account balance (2,6). Specific design features of Type III transponders are discussed further in subsequent sections.
H-5 In read-only configuration, the transponder memory contains the identification number, which designates the vehicle class, individual, and/or company account number. This information is programmed by the tag manufacturer and is not designed to be altered by the user. Typical read- only transponders have 16 to 32 bytes of memory (8). Since only an identification code is stored, this amount of memory is adequate. For Type II configuration, the memory is divided into read and write portions. Similar to the Type I, the read-only memory contains the fixed identification code which is not designed for alteration by the user. The write portion of the memory contains the toll plaza number, date, time, transaction number, transaction amount, and account value. The write portion of the memory is altered for each transaction (6). Type II transponders may have 64 bytes to 2-3 kilobytes of memory. A Type III transponder contains a microprocessor and allows far greater data storage, ranging from 8 kilobytes to 1 megabyte of memory (9). This configuration supports the driver interface features, a detailed account transaction history, current balance, and multiple accounts. Electrically Erasable Programmable Read-Only Memory (EEPROM) is used for both fixed and variable data, while Random Access Memory (RAM) is used for variable data only (9).
Signal Parameters
The RF signal is described by the frequency at which the message is sent, how the message is sent from the transponder, type of modulation, and data transmission rate. The Federal Communications Commission (FCC) authorizes three bandwidth for low power, unlicensed communication. The bands are 260-470 MHZ, 902-928 MHZ, and 2400-2484 MHZ. The downlink portion of the handshake, sent from the transceiver to the transponder, is usually broadcast within the 902-928 MHZ bandwidth near 915 MHZ (5). This frequency resides within the radio frequency spectrum (30 MHZ to 1 GHz). Since the 902-928 MHZ bandwidth is assigned differently by other nations, the downlink frequency for ETC systems worldwide is near 2.45 GHz or 5.8 GHz. These frequencies fall into the microwave spectrum (2 GHz to 40 GHz). Active transponders, which broadcast a signal in the uplink portion of the handshake, generally operate at 40 to 50 MHz (9).
The communication method (dependent on whether the tag is active or passive) and type of modulation also result in incompatible RF systems. Passive tags receive the signal from the transceiver, modify it, and reflect it back to the source in a common method referred to as ‘modulated backscatter.’ This method is advantageous because it consumes less energy, defines a more precise read zone and requires less expensive electronics (10). The tag consumes very small amounts of energy and therefore can have an extended lifetime with only a very small battery. Active tags have both a transmitter and receiver to broadcast a response signal to the reader. The frequency used for the transmit and receive messages may be a single frequency or may occur over a spread spectrum. Modulation refers to the way the signal (electromagnetic wave) is altered to carry the data. Amplitude Modulation (AM) and Frequency Modulation (FM), Amplitude Shift Keying (ASK), and Frequency Shift Keying (FSK) are common methods, although several other modulation schemes exist (5,6).
The entire ‘handshake’ process must occur within milliseconds to allow the vehicle to progress through the facility at high speed. For a read-only transponder, the handshake consists of; (1) an interrogation signal from the transceiver, (2) which identifies the account number, (3) a reflected signal back to the transceiver, and (4) verification that the identification number is valid. Thus, the signal travels one cycle to complete the transaction. In a read/write handshake, once the
H-6 tag information is verified, the transceiver sends a message to record the transaction in the tag memory; the transponder then replies with a confirmation that the information has been written into its memory, and the transceiver records a successful transaction. In this case the signal travels two cycles to complete the transaction and contains more information. The critical data transmission rates must therefore be faster for read/write systems since a more complex handshake occurs (6). This entire process must allow for misreads, and therefore the communication should be repeated several times, if necessary, while the vehicle is in range of the transceiver. Data transmission rate is measured in kilobits of data per second (kbps) or in the size of the bandwidth required, measured in Hertz (5). The data transmission rate may be 30 kbps to several hundred kbps depending on the transponder. The actual rate is dependent on the amount of information transmitted, encryption for security purposes, speed of the vehicle, and the communication range (6). To allow vehicles to pass through the system at high speed with a high probability of a successful read, the transaction must be completed in less than one second (6). ITS America suggests a tag misread rate of one in 10,000 at a vehicle speed of 100 mph (11).
Smart Cards
Smart cards were first introduced in the French banking and telephone industry and were applied for use in the London subway system in the early 1990s (1). In the last 2-3 years, the technology has been introduced in North American transit systems and is being tested by U.S. banking and credit card industries. Reduced manufacturing costs, an increase in credit card fraud, and the potential for enhanced service are identified as the reasons for smart card proliferation in the U.S. (12). A smart card is a tiny personal computer, no thicker than a standard credit card, consisting of a microprocessor and memory chips capable of storing thousands of bytes of data. The terms memory card and integrated chip (IC) card are often used interchangeably when referring to a smart card. However, a smart card has the distinct ability to perform calculations and logical functions by virtue of its microprocessor (12). The card actually holds value in contrast to a typical magnetic stripe card which allows access to information in a central computer system. Smart cards are classified by the manner in which they communicate with the card reader as either contact, contactless, or hybrid cards. Cards which must physically touch or be inserted into the reader are referred to as contact cards. Proximity, or contactless cards, must be brought within close range of the reader and use either RFID or remote coupling to communicate. Hybrid cards can communicate with the reader by either a physical contact or proximity methods (13). A comparison of the advantages and disadvantages of contact and proximity cards is shown in Table 2.
A smart card consists of memory areas, a central processing unit (CPU), protection circuits, reset circuit, clock, and input/output area (14). The card memory consists of electrically programmable, read-only memory (EPROM) or electrically erasable, programmable read-only memory (EEPROM). EPROM data, once added to memory, cannot be erased. EEPROM memory can be erased and modified as needed. The total memory storage is in the range of several kilobytes, around the equivalent of two standard pages of text. Both volatile and non-volatile memory are used. All external access to the card is controlled by the CPU which reads instructions from the card memory. The instructions are referred to as a smart card operating system, similar to the disk operating system (DOS) function in personal computers (14). The card is pre-programmed to make decisions based on the format of the request. The protection circuit functions to avoid electrical damage to the card or counterfeiting. The reset circuit stores basic information about the card,
H-7 including manufacturer and working frequency. The card reader interrogates this circuit to determine whether the card belongs in the system or not. The clock functions to coordinate the card’s internal operation and synchronize the communications with the reader. The clock speed generally operates between 5 and 14 MHZ. The clock speed and frequency are defined by International Standards Organization (ISO) Specification 7816. The configuration of the input/output area is dependent on whether the card communicates with physical contact or in proximity format (14).
Table 2. Contact and Proximity Smart Cards in Transit Systems (1,5).
Card Type Advantages Disadvantages
Contact C International standards developed allow C Lower passenger throughput multiple vendor sources C More difficult to use for disabled riders C Use by banking/credit card industry may C Medium life span potential due to contact promote partnerships wear C Interference negligible; highest security
Proximity C Potential for higher passenger throughput C Higher cost C Easier to use for disabled riders C Lack of international standards C Long life span potential, no contacts C Potential for interference; lower security
Contact Cards
Contact cards must be inserted into a reader to transmit information. They were the first type of smart card and are still the largest number in circulation (13). Contact cards have eight metallic contacts connected to embedded circuits which allow data and power to pass between the card and the reader as they touch. Each of the contacts have different card functions including communications, power and clock control (14). The ISO has established strict guidelines (ISO 7816) for the location of the contacts on the card and in the reader to ensure correct coupling. Passive cards receive power through the metal contacts while active cards have an embedded battery. Contact card readers may require more maintenance since the physical contacts eventually wear and corrode (13).
Contactless Cards
Proximity cards communicate with the reader via radio frequency inductive coupling or capacitively close coupling techniques. In the former method, the card reader contains an induction coil which couples with a coil in the card. The radio frequency signal sends power to the card and carries the transaction signal as well. An active card powers up using its own internal battery. The card transmits a signal using the same coil or a separate antenna (13). Such a small amount of power is used that FCC licensing is not required and a range of frequencies may be used (5). The size of the antenna and signal strength determines the maximum distance between the card and reader, typically from one inch (2.5 cm) to a foot (30 cm). If the card power supply is passive, the distance also depends on the power needed to activate the card. The signal between the card and reader is broadcast in the frequency range of 50 to 200 kHz. The data transmission rates are on the order of 19.2 kbps to several hundred kbps, with much faster rates being developed (6,13,15).
H-8 Close coupling uses inductive and capacitive techniques to transfer the data. Embedded in the card are two or more areas of metal foil that are positioned to align with identical areas within the reader. The pair of metal foil areas create the capacitor used for data transfer. The card must be inserted into a reader for communication, so therefore functions the same as a contact card from the user’s point of view. The main difference from the operator’s point of view is the lack of metal to metal contact points in the reader which may wear and corrode (13).
Hybrid Cards
A card that can communicate using either contact or contactless techniques, depending on the configuration of the reader, is referred to as a hybrid (1). One example of a hybrid is a proximity card which also contains a magnetic stripe across the back. This configuration may be optimal when magnetic stripe card systems are converted to smart cards. Additionally, the system may want to retain magnetic stripe readers for infrequent users not needing a more expensive smart card. Another example is a proximity card that can also function as a contact card, depending on the application. The contact card is preferred by the banking and credit card industry with the proximity card preferred by transit agencies, and thus, the hybrid may be optimal for multi-uses (1).
European AFC and ETC Projects
European countries are several years ahead of the United States in developing smart card IP systems. This is partially due to the trend in Europe toward private finance and the use of tolls to finance construction and maintenance (16). Another difference is the acceptance of congestion pricing as a tool for travel demand management. The DRIVE/ATT program, launched jointly by several European countries in January of 1992, is comparable to the development of a national ITS architecture in the U.S. The DRIVE/ATT program sponsored several programs testing automatic debiting and integrated payment systems. The ADEPT (Automatic Debiting and Electronic Payment for Transport) project was an ETC field test using smart cards inserted in a transponder (16). The GAUDI (Generalised and Advanced Urban Debiting Innovations) project tested smart cards in various transportation applications (4). Table 3 summarizes the application, findings and future plans of each test site within the ADEPT and GAUDI projects.
ADEPT
The ADEPT project was funded by the European Union and involved the partnership of 16 organizations from industry, research institutes, and infrastructure owners in eight countries (16). The main objective of the ADEPT project was to field test a microwave system for ETC. The IVU (In-Vehicle Unit) consisted of a transponder, contact smart card, and a driver interface. The ADEPT concept envisioned a modular system that could be upwardly compatible based on the owner’s needs. The transponder was designed to reflect the transceiver signal at a communication frequency of 5.8 GHz. To achieve future compatibility, a core architecture common to all sites was chosen along with application-specific components. The five test sites were located in Goteborg (Sweden), Cambridge (U.K.), Thessaloniki (Greece), Lisbon (Portugal) and Trondheim (Norway). The Trondheim experiment is discussed under the GAUDI project (16).
H-9 Table 3. Summary of ADEPT and GAUDI projects (1,16-23).
Location Major Application Major finding Future Plans
Goteborg, ETC and two-way Smart card-based transponder can: Full-scale Sweden communication link (1) conduct transaction at high speed implementation in with driver (2) provide driver with traffic information Stockholm: Fall 1997
Cambridge, Congestion pricing Congestion pricing, distance-based Further testing U.K. schemes charging, and open tolling may be accomplished with the ADEPT system
Thessaloniki, ETC and two-way Smart card-based transponder can: Possible full-scale Greece communication link (1) conduct transaction at high speed implementation on with driver (2) provide driver with parking information Greek highway system
Lisbon, Two-way Smart card-based transponder can: Further testing Portugal communication link (1) provide information/guidance for with driver parking (2) allow user to reserve a space in advance
Dublin, Integrated Payment Positive card-user response, desire for Further testing Ireland System additional services on card and increased visual feedback on card balance
Marseille, Integrated Payment No results available Field trial ongoing France System
Trondheim, ETC, Congestion Trip times changed to avoid toll, no Implement toll rings Norway pricing reduction in total number of trips. along inner city zones
Barcelona, Vehicle access control System works effectively to manage on- Planned expansion to Spain for special events and street parking, promote transit, and reduce other city areas pedestrian priority congestion areas
Bologna, Vehicle access control System works effectively to manage on- Planned expansion to Italy to reduce congestion street parking, and reduce congestion and other city areas pollution
The Goteberg test site was located south of the city on both directions of a four lane urban arterial. On October 1, 1992, the world’s first multi-lane transaction, with real-time debiting from a smart card, occurred at this site (17). The demonstration tested two types of payment methods: deducting pre-paid value from the card or debiting a central account using information contained in the card. One of the features of the IVU allowed the user to choose either payment option. The unit automatically debited the central account if the balance on the smart card is insufficient. Three potential applications of the system were identified: (1) use of the driver interface to provide traffic information; (2) use of the smart card to provide information about the vehicle, or cargo, and (3) use of the smart cards to pay for parking. The second application was proposed to allow monitoring of the transport of hazardous goods. The test results concluded that a smart card (in pre-paid or debit format) was a feasible and reliable system. A full scale ETC system for a proposed toll ring in Stockholm was planned to open in the Fall of 1997 (17).
H-10 The Cambridge project was intended to demonstrate use of the ADEPT system for congestion pricing. The test site consisted of a two transceivers placed at entrance and exit points on opposite sides of the city (18). Also tested was a card service station (CSS), a personal computer that issued smart card, updated account balances and printed out the transaction history. In addition to the IVU, a sensor was attached to the vehicle’s odometer to measure the distance the vehicle traveled in the system. Three charging algorithms were developed; congestion pricing, distance pricing and open tolling. The congestion pricing algorithm calculated the vehicle speed every 3.75 seconds and if the speed was less than 11 km/hr (7 mph), a unit of charge was deducted from the smart card balance. The distance charging algorithm deducted a unit of charge from the card balance every 500 meters. The open tolling algorithm charged a fixed number of units as the vehicle passed the entry point. Two government vehicles were equipped with IVU’s for the successful demonstration conducted in October 1993. Since this was a demonstration project only, the results were used to warrant further testing (18).
The test site in Thessaloniki was located at an existing toll station 25 km (16 mi) from the city center on one direction of a six lane freeway. The system was placed 500 meters upstream of the existing toll facility (19). Non-stop lanes were provided downstream with an enforcement system to verify that the transaction had occurred upstream. A green light on the transponder signaled a successful transaction to the driver while a warning light indicated a failed transaction, giving the driver time to change lanes and pay the toll manually. The main project objectives were to test the ADEPT system and investigate information exchange with the IVU to provide traffic information and space availability at a major truck parking facility. The system may eventually be implemented on the Greek highway system (19).
The ADEPT system in Lisbon was tested to determine the feasibility of using the IVU unit to provide a two-way communication link for parking information. This system was based on the PARCMAN prototype developed in a previous DRIVE/ATT program (20). Two parking facilities and two radial arterials leading to the center of the city were equipped with the ADEPT system. By using keypads on the driver interface, the user could either request information about parking availability at the two facilities or attempt to reserve a space. The time of the requested space, along with the respective facility was input by the driver. The smart card within the transponder was then charged a fee to hold the reservation and for the first half hour of parking. The computer database keeping track of occupied and vacant spaces updated its information in 15 to 30 minute intervals (20).
GAUDI
The GAUDI project, also part of the DRIVE/ATT program, focused on smart card development to improve urban mobility and for travel demand management. The common technology used was a contact smart card. The GAUDI consortium consisted of two highway authorities and three transit agencies in five European Countries (4). The cities of Dublin (Ireland) and Marseille (France) were test sites for integrated payment systems using smart cards. The Trondheim (Norway) toll ring was developed to raise revenue for infrastructure improvements and travel demand management. The cities of Barcelona (Spain) and Bologna (Italy) tested the system for vehicle access control. The objectives of the GAUDI project included: promote card-based interoperability across Europe, effect a modal shift from private to public transport, and explore travel demand management (4).
H-11 The integrated payment system test in Dublin and Marseille used a contact smart card as the common form of payment. The Dublin trial involved four service providers: one bus route, twenty pay phones, one parking lot and one toll bridge (21). The contact card had an electronic purse, accepted by each service provider along with independent applications for each service. The fare products consisted of monthly and weekly bus passes, telephone calls and season parking passes. Personal computers were used to reload card value. The trial ran from February to May 1994. The Marseille experiment included seven service providers: three transit agencies, a regional rail service, and a park-and-ride facility with connecting bus route and a toll tunnel. A portable transponder was developed to make the card function like a proximity card. The user had to push a button on the device to activate the card in the presence of the reader. The transponder also displayed the current balance of the electronic purse and the number of fare products for each service. In the park-and-ride application, the user received a discount on parking when followed by a transit ride. The seven services were integrated in a phased basis in the final months of 1994 (21).
The Trondheim project received funding from both the ADEPT and GAUDI consortium. Several cities in Norway, including Bergen and Oslo, finance road infrastructure improvements by charging vehicles to enter the city center (22). The Trondheim toll ring surrounds the city and is located such that about 60 percent of the city’s inhabitants live outside the city. Many of the residents of Trondheim need to cross the ring to commute to work or conduct their business. The toll ring operates Monday to Friday from 6:00 am to 5:00 pm. Vehicles entering the city outside this time may do so at no cost, and the toll decreases by 25% after 10:00 am. The actual toll charged was approximately 1 percent of the average daily wage, and therefore, was not expected to have a significant effect on travel behavior. The toll ring transponder is a read-only Type I tag operating at the European standard 5.8 GHZ frequency. The ADEPT system, with the standard smart card- based transponder and driver interface, was planned for testing (22).
Vehicle access control during selected hours of the day was the primary focus of the GAUDI projects in Barcelona and Bologna. The Barcelona experiment was intended to prevent parking in nearby residential neighborhoods during the Olympic Games in 1992. A second access control area was established in Barcelona to promote street space for pedestrians and vehicle users (23). In Bologna, the system was designed to reduce vehicle congestion and improve air quality in the historic center of the city. Drivers were alerted to access-controlled areas with conventional traffic signs and smart card-based transponders were used to validate entrance. An intercom/video conference link was provided for non-equipped vehicle access. The system was designed to be compatible with the tag equipment used by the toll highways accessing Barcelona. Video surveillance was monitored at a control center for enforcement. The test results indicate that the system is practical and enforceable for even high volumes of traffic. Expansion to other areas of each city is being planned (23).
H-12 SMART CARDS IN AUTOMATED FARE COLLECTION (AFC)
Several reports have documented the benefits of smart cards to transit operators (1,24). Transit agencies testing both contact and proximity cards have found significant advantages to using proximity cards. Therefore, this paper will focus on the development of proximity cards for AFC. This section includes a brief overview of four existing or planned integrated fare payment systems in Chicago, Seattle, Ventura County (California), and Washington DC. The member agencies, stage of implementation, and plans for expansion of each project will be discussed. Information for this overview comes from telephone interviews and current literature. It should be noted that these four cities are only a few of the number of cities testing and implementing smart cards. Other North American projects using either contact or proximity cards include: Ajax and Burlington (Ontario), Oakland (California), Ann Arbor (Michigan), Wilmington (Delaware), Atlanta, and San Francisco (1). The technical issues associated with smart cards; international standards, information structure for multiple application cards, and implementation with other fare media are developed in this section. A comparison between contact cards and proximity cards in transit also appears in this segment. An overview of the economic advantages and disadvantages of smart card systems in transit follows. An additional challenge to integrated fare payment are the institutional conflicts which may surface during the planning stage regarding the appropriate fare media, ownership, and administrative costs. The various inter-agency agreements necessary to implement the system are discussed to conclude this section. A summary of the four proximity smart card projects discussed in this paper is shown in Table 4.
Selected Proximity Smart Card Projects in U.S. Transit Systems
Chicago
The Chicago Transit Authority (CTA) is developing an AFC system which allows payment with a magnetic stripe card, the “TransIt Card,” a proximity smart card, the “Gold Card,” or cash. Magnetic stripe cards will be retained because they are cheaper to provide for infrequent users and those who do not want to pay for the convenience of a smart card. Currently the magnetic stripe cards are being used while the proximity card is still under evaluation and is currently used as an identification and location device for CTA maintenance personnel. The card functions to open doors for employee access in restricted areas. Magnetic stripe and proximity cards can be increased in value at automated vending machines by inserting cash. The current project focus involves the transit authority’s rail system but the AFC equipment will eventually be installed in buses as well. A station information center will be located at several rail stations to allow employees to monitor the fare collection equipment. A proximity smart card will be required to access the center (25,29).
H-13 Table 4. Selected Proximity Smart Card Projects in U.S. Transit Systems (1,25-28).
Location No. Project Scope Current Status Future plans Agencie s
Chicago, 3 Bus, suburban bus, Cards used by maintenance Issue cards to users Illinois light rail, heavy rail personnel for identification and location purposes
Ventura 7 County bus transit Cards issued for sale January Implement in County, agencies 1996 commuter rail system California
Seattle, 6 5 transit agencies and Bid phase for design Phased Washington ferry operator consultant Summer 1996 implementation circa 1999
Washington DC 1 24 rail stations, 21 Completed 1-year Implement on all bus buses (3 routes), 5 demonstration in February routes and park-and- park-and-ride facilities 1996 ride facilities
Since the system in not yet operational, only the project objectives and future plans can be discussed at this point. The system objectives, categorized into user services, agency operations, and marketing are included in Table 5. Users will benefit from the system by not having to carry exact change or cash, even when transferring to another transit mode. Disabled users will find the proximity cards easier to use than tokens or magnetic stripe cards that must be inserted in a slot. A fare structure that recognizes a transfer, or two consecutive trips, will be developed to offer a discount on fare for the second trip. The high maintenance turnstiles will be eliminated and replaced with card readers and enter-only gates. The gates are designed for one-way access at unattended rail stations and will only accept magnetic or proximity cards. Once the CTA system is operational on both the rail and bus system, plans include expansion to PACE, a suburban bus transit agency, and METRA, the region’s heavy rail system (25,29).
Seattle
Seattle/King County Metro is 3-4 years from actual implementation of a smart card AFC system, but a wide range of activities are in the planning stage. An initial study was performed to compare the potential benefits of different electronic payment media and the results favored the proximity smart card for future development. A second study was published in January of 1996 to examine the institutional aspects of an integrated payment system, including involvement in the banking industry, inter-agency cooperation, and the potential development of a clearinghouse to issue the multi-use cards and maintain the user accounts (30). Four regional transit agencies and the local ferry operator have been involved in the AFC plan. The project is currently letting a contract for the design, implementation and oversight of the system. Proximity card demonstrations have been run on two buses, mainly to increase public awareness. Additional testing will be conducted to determine the effect of possible sources of interference, including marine radio systems. The functional design of the system is projected for completion in 1998, with phased implementation in late 1999 (1,27).
H-14 Table 5. Objectives of Chicago Transit Authority AFC Project (29).
Area System Objectives
User C Eliminate need for exact fare, reduce revenue processing costs Services C Provide an easy transfer among modes C Provide multi-modal travel that is convenient C Accommodate the requirements of the disabled
Agency C Eliminate manual processing of rail passengers Operations C Replace aging, high maintenance turnstiles C Reduce the potential for internal and external fraud
Marketing C Provide flexibility of special fare structures C Generate, transmit, collect and report ridership data for planning purposes
The future AFC system must be responsive to the needs of businesses since approximately 80 percent of transit trips in Seattle are employer-subsidized. To attract continued and increased employer support, the system must make the billing and payment process more “user-friendly” to business. METRO is also studying possible partnerships with local banks to provide limited services such as revenue deposit and card recharge functions. The concept of a regional clearinghouse, to provide a central point for revenue collection and ridership data, is also being studied (27).
Ventura County, California
As of January 1996, transit users in Ventura County can purchase a proximity smart card, known as the “Smart Passport” to pay fares on any of the seven bus transit agencies within the county. The smart card system was developed as part of the Southern California Advanced Fare Payment Media Test, sponsored by the Federal Transit Administration (FTA) and the California Department of Transportation (CalTrans) (1). The field operational test (FOT) was performed on one bus route within three Los Angeles area transit agencies (Gardena, Torrence and Los Angeles Department of Transportation) at the end of 1994. Approximately 600 smart cards were sold to users during the six month demonstration project. The goal of the test was to determine the reliability of smart cards using both contact and proximity cards for purposes of comparison. The results of the FOT, discussed further in the next section, indicated that smart cards work well and have significant benefits to both the transit agency and the user (24).
With funding from the FTA and CalTrans, the successful test results in Los Angeles supported a full scale implementation in adjacent Ventura County. Ventura County’s seven bus transit agencies formed the first multi-agency smart card system in the U.S. The Ventura County Transportation Commission (VCTC) acts as the regional clearinghouse to collect the ridership data and apportion the revenue to member agencies (26). Cards may be purchased by regular mail, e- mail, phone orders and in person at all county city halls. The card value can be increased in ten dollar increments via phone, e-mail, in-person at any city hall building, or by giving the bus driver a personal check or money order (26,31).
H-15 Washington, DC
Washington DC’s Metropolitan Area Transit Authority (WMATA) completed a one year test of its Go-Card in February of 1996. The Go-Card, a proximity smart card, was tested in the rail system and is planned for use on the bus system and several WMATA park-and-ride lots. Cards were given to 5,000 Metro employees and 1000 selected riders (1). Automated vending machines were installed to display card balance and allow users to increase the card value with cash. On entering the bus, the maximum fare (three zones) was deducted from the card value. If a one- or two-zone ride was taken, the passenger used the card to “check out” at either the front or rear door and the appropriate value was restored. This “check out” system was also used at the park-and-ride lots. Card readers were also installed at entrance and exit gates of the rail system. Data from each of the subsystems were sent by modem to WMATA’s Central Computer System to apportion the revenue. The data from AFC system also include the station origin and time of entry for each rider, along with the number of people on each bus trip (1,28).
WMATA plans expansion to all bus routes, transit stations, and park-and-ride lots to occur over the next several years. Additionally, other regional bus systems, rail services (Maryland Rapid Transit and Virginia Rail), and possibly public telephones, will use the Go-Card in the future (31).
Summary
Several observations may be made about these smart card projects. First, the smart card will not likely become the only means of fare payment, at least in the foreseeable future. Most AFC systems are being designed to accept a combination of smart cards, magnetic stripe cards, tokens, or cash. The media preferred by the user are likely a function of: willingness to pay for the added convenience, frequency of transit use, frequency of multi-modal use or transfers, and ability to use the card for non-transit purchases. Second, phased implementation seems to be the preferred plan, with cards tested and established in one mode (bus/rail) and then to other modes. A third important factor is the means of issuing the cards and establishing a convenient system to increase card value. Washington, DC used automated vending machines in their demonstration, while Ventura County uses phone, e-mail, and service centers. Several agencies are also studying the concept of a central clearinghouse structure to collect the ridership data and apportion revenue. Lastly, the proposed flexibility of the fare structure offers a variety of marketing strategies to increase ridership and reward frequent users with discounts. Providing attractive options to companies willing to subsidize their employees’ transit costs may be yet another way to increase ridership.
Technical Issues
Standards
The structure and communication modes for smart cards are relatively standardized in comparison to vehicle transponders. The International Standards Organization (ISO) has been developing standards for both contact and proximity cards over the past decade (14,32). Smart card standards are nearly completed for contact cards and are well underway for proximity cards. Table 6 summarizes the ISO standard numbers, titles, and year of completion. The contact card standards are divided into definitions of card size and thickness (7816-1), the position and size of the contacts
H-16 on the card (7816-2), and the communication signal between the card and reader (7816-3). The only completed standards for proximity cards define the card size and thickness (10536-1) and the position and size of the antenna and receiver chips (10536-2). Standards defining the communication signal (10536-3,4) are still being drafted according to available information. A smart card which stores data from different applications is similar to a disk drive which contains files and directories. Standards 7816-4,5,6 define the file structure, data elements and how different applications on the card exchange data. Standards listed in Table 6 are listed as completed, yet still undergo a constant process of revisions and addendums. Therefore, the standards are continually developing and still may not completely describe the data structures and communication methods (33).
Table 6. ISO Smart Card Standards (32).
Contact Cards Proximity Cards
Number Title Year of Number Title Year of completio completio n n
7816-1 Physical Characteristics 1987 10536-1 Physical Characteristics 1992
7816-2 Dimensions and Locations 1988 10536-2 Dimensions and Locations 1995 of Contacts of Coupling Fields
7816-3 Electronic Signals and 1989 10536-3 Electronic Signals and Still in Transmissions Protocols Mode Switching draft phase
10536-4 Answer to Rest and Still in Transmission Protocols draft phase
Applicable to Both Contact and Proximity Cards
Number Title Year of completio n
7816-4 Inter-Industry Commands for Interchange 1995
7816-5 Registration of Applications in IC-Cards 1994
7816-6 Inter-Industry Data Elements for 1996 Interchange
Card Features
For the purposes of this paper, the most important card feature is its data file structure that enables the card to store data from different applications, or agencies. A distinction should be made between a multiple application card and a card used for multiple services. A multiple application card holds independent applications which are given access according to the communication signal
H-17 sent by the reader. For example, a single card holds health information, employee identification and transit services in different data files. The card reader is only allowed to access information from its respective application and cannot read other files. An example of a card for multiple services is an electronic purse. The card readers at different stores are configured similarly and access information from the same files on the card (12). The card could be configured to function as both types as in the case of the smart card used in the Dublin ADEPT project. The card could function as a multiple application card, with a file containing a prepaid bus pass, or as a card for multiple services if the user paid for the service with the electronic purse portion of the card. Thus, a single card could have the capability to function as a health card, driver’s license, employee identification, bus pass and credit/debit card. However, for reasons of security, the card issuer or user may wish to have certain data reside on separate cards.
U.S. transit agencies are looking predominantly to the proximity card systems for future AFC. The main reasons for this preference include beliefs that: (1) a proximity card reader requires less maintenance since there are no metal contacts, (2) disabled riders will find the cards easier to use, and (3) the proximity card has a longer life span (25,28). The belief that passenger throughput is higher for proximity cards is also popular. However, during the Southern California Advanced Fare Payment Media Test, researchers found no significant difference in boarding time for passengers using contact cards to those using proximity cards (24). Conversely, a study by Cubic Western Data found a 20% increase in passenger throughput (34).
Economic Issues
Card Cost
A major disadvantage to smart card systems is the high unit cost of the card and the cost of the card readers. An additional cost element is the cost of the supporting infrastructure. Equipment is required to provide convenient means for; card purchase, adding value to the card, and storing ridership and revenue data in a central system. All of these elements have both purchase costs and operating costs which must be considered. Cost savings are also realized from a reduction in maintenance, token and cash processing, magnetic tickets, and number of ticket agents. An additional factor is the potential for increased revenue from reduced card fraud, greater convenience, and marketing with flexible fares and discounts for frequent use. A further discussion of purchase costs, operating costs, savings, and other financial benefits from smart card AFC systems can be found in TCRP Report 10, “Fare Policies, Structures, and Technologies” completed in May of 1996 (1). A comparison of fare collection costs between smart cards and conventional fare boxes is found in Reference 24. The current and proposed implementation of smart card systems in several U.S. transit systems indicates that smart card technology is economically feasible, although some economy of scale must be assumed.
The price of smart cards generally ranges from $4.00 to $10.00 a piece while magnetic cards and tickets are less than $1.00. Costs depend on the card type, memory, processing capability, and the volume purchased. Further development of the technology is expected to decrease these costs to under $5.00 a piece (1). The initial purchase price is much less drastic when the estimated 5-10 year life span of the card is considered. Due to the high cost of the card, (usually borne by the agency) it is beneficial to have the cards retained for use for long periods of time (1). There are
H-18 several strategies for influencing users to retain their cards. The agency can (1) offer a discount when value is added to the card (as in Ventura County), (2) set a high initial purchase price, or (3) charge the user for the cost of the card (1). The smart card, however, may not be ideal for the infrequent or one-time user. Magnetic stripe cards or tickets, cash, or tokens may be the preferred means for a segment of transit users. Therefore, an AFC system must be able to accept one or more forms of payment besides the smart card.
Infrastructure Cost
Transit agencies interviewed for this paper also expressed concern about infrastructure costs for card purchase and adding value. Two different types of systems have been described in this paper. First the Ventura County system uses a toll-free phone line, regular mail, e-mail, bus drivers and service centers in city hall buildings to sell and add value to smart cards. In the WMATA demonstration, cards issued to riders could be increased in value at automated vending machines. Since smart card systems are still extremely new, it is difficult at this time to make any statements on which system is more cost effective and/or preferred by users. A cost-effective means of providing locations to replenish card value may be to involve the banking industry’s network of ATM machines. This concept is discussed further under institutional issues.
Institutional Issues
The regional fare integration concept implies both a multi-use card (bus, rail) and a multi- agency card (accepted by two or more transit agencies). The challenges to development of a multi- use card within a single agency lie mainly in the different configurations of the card readers, while the challenges to a multi-agency card are highly institutional in nature. Required agreements between agencies must determine the appropriate fare media, ownership of the fare media, allocation of administrative costs, and apportioning of revenue (1). The Ventura County Transportation Commission currently represents the only operational smart card-based system that has achieved regional integration. However, regional fare integration has been established through magnetic stripe technology and thus, several of the necessary agreements may already exist in some situations. Fare integration involving two or more agencies may occur if: (1) the system is operated jointly by one or more of the agencies, or (2) the system is operated by banks or contracted to a regional clearinghouse. A system operated by the agency would likely represent a closed system, or one that issues cards to pay for transportation services only. An open system, a result of bank-issued cards, is one in which the card can be used to purchase a variety of goods and services, including transportation services (30).
Closed Systems
In an integrated fare system administered by transportation agencies, it is generally required that a single agency take the initiative to start the project and see it to completion. The smart card projects reviewed in this paper are prime examples of this fact. The CTA, Seattle/King County Metro, WMATA and VCTC have each been the primary champions of the smart card system. Smaller agencies within each region are expected to convert to smart cards once they are established by the lead agency over the next few years. These agencies include suburban bus systems, ferry operators, rail lines and parking facilities. The lead agency may act as the clearinghouse to collect
H-19 the data, make payments and issue ridership reports to the members. Bay Area Rapid Transit (BART) in San Francisco, developed the first integrated fare system in the U.S. using its magnetic stripe cards. A study completed in 1995 for BART recommended an expanded regional IP system based on proximity cards. The study also envisions a partnership with private entities to maintain the AFC equipment and perform clearinghouse functions (1). A Seattle study made similar recommendations (30).
Open Systems
The second approach is to have a bank or private entity initiate and administer the smart card system. In this case, the agencies contract out the costs, responsibility, and liability related to issuing and maintaining the cards in return for some form of transaction fee. The major advantage of this arrangement is that the infrastructure supporting the card is established by banks through automatic teller (ATM) machines. This may be the most attractive option for smaller agencies that do not have the financial resources to initiate and manage a new AFC system. The disadvantage of this arrangement is that the agency no longer has full authority over its fare collection system and no longer collects revenue from pre-paid cards. The Metropolitan Atlanta Rapid Transit (MARTA) system, has agreed to accept pre-paid debit cards from three local banks in the Summer of 1996 (36). The card will originally be disposable (its value cannot be increased), and eventually be rechargeable. The New York Metropolitan Transportation Authority (NYMTA) established a subsidiary to expand its MetroCard (currently a magnetic stripe card) to regional transit authorities, telephone, and retail. A major New York-based bank will likely form a partnership with NYMTA in the near future to perform clearinghouse functions (1).
The acceptance of credit cards is a special case of the second arrangement. In May 1995, the Phoenix Transit System began to accept credit cards for fare payment. The credit card numbers are sent to the credit card company at the end of each week, and the transactions appear on the cardholder’s monthly bill. The credit card company, in turn, reimburses the transit agency the next day for trips purchased. The transit agency has no way to verify the card in “real time.” Invalid numbers are programmed into the card reader so that the card cannot be accepted again. The advantages to this arrangement include; reduced expense (cards do not have to be purchased by the agency), and a low transaction fee ($0.05 in the Phoenix case) may be negotiated (1).
Regulation E
A final institutional issue is the effect of government regulations on smart card-based AFC systems. Regulation E is the implementing regulation of the Electronic Fund Transfer (EFT) Act of 1978 intended to protect consumers from electronic theft and fraud. The regulation defines the terms of disclosure for EFT, conditions to provide service, requires documentation by receipts and account statements, and outlines customer liability and resolution of transaction errors (37). Since transit agencies are issuing pre-paid smart cards or accepting bank-issued debit cards, Regulation E applies. The Federal Reserve Board is proposing to exempt the type of cards used for transportation services by making several distinctions from cards typically used in ATM machines. To summarize the recommendations, typical cards used in a closed revenue collection system would be completely exempt. Cards operating in open systems (electronic purse) would be exempt so long as the maximum stored value is $100.00. This proposal attempts to avoid burdensome disclosure requirements while still offering some degree of protection to the consumer (37).
H-20 SMART CARDS IN ELECTRONIC TOLL COLLECTION (ETC)
While Type I and Type II transponders are well suited for current applications within a single toll authority or inter-agency group (IAG), only a Type III transponder has the data storage and processing capabilities to conduct transactions using EFT from an electronic purse, and may allow debiting from a central account as well (9). The Type III has great potential to be used in further vehicle-based applications, such as parking and access control. The smart card, conversely, is destined for broad use in person-based applications. A study completed for the Federal Transit Authority in May 1995 determined that the vehicle-based transponder and person-based smart card have significantly different requirements (5). These requirements differ in read range, size and convenience of use. Therefore, a Type III with two components, a transponder and a smart card, is necessary to accommodate both requirements. The transponder provides the power and communication link to the transceiver and the smart card performs the transaction processing and memory storage functions. When the vehicle-based application is not needed, the card is removed for use in person-based applications.
Besides the added convenience of a single payment medium, the smart card-based transponder may be ideal in several situations. At park-and-ride lots, where a person leaves his/her vehicle to complete a journey via transit, a single card could be used to pay for both transit and parking. The smart card-based transponder may be ideal for trucks at international border crossings. The card would be used to store information about the cargo, destination and driver. In an open IP system, the smart card-based transponder may also provide increased convenience for commercial vehicle operations. The smart card could be identified with a project account number or shipment, and provide both a single payment medium and receipt for tolls, gas, food, and lodging on long trips.
This section includes a brief overview of selected ETC facilities recently opened in the U.S.; California FasTrak, Illinois I-Pass, and Virginia FasToll, each using among the most advanced (Type II and Type III) transponders currently available. The size of each system is shown in Table 7. The format of this overview is to describe the current transponder configuration, and then discuss the feasibility of introducing a smart card interface into the system. The source of information on project status was a phone interview conducted with the respective ETC vendor. Technical issues discussed in this section include the influence of industry standards and the potential features of a smart card- based transponder. The economic factors which may encourage or discourage this development are discussed next. An overview of the institutional agreements which must be made among vendors and toll authorities to develop an IP system concludes this section. The technical, economic and institutional issues are developed from both current literature and from tag vendor phone interviews.
Selected U.S. ETC Facilities
California FasTrak
The Foothill Transportation Corridor, a publicly owned facility, began operation in 1994 in Orange County. The ETC system was designed to use a Type III transponder incorporating a smart
H-21 card, called the FasTrak card (38). However, significant technical and marketing problems were evident after the introduction of this device. The smart card tended to drain the transponder battery within six months. It was designed to be removed from the transponder while not in use, but the majority of drivers left the card in the transponder all the time. The main reason for this failure was the fact that the card could not be used anywhere else but in the toll application. Therefore, users had no incentive to remove the card from the unit. The second problem was the $10.00 annual fee charged to the consumer for using the smart card. Coupled with the battery problems and lack of other applications for card use, the fee was not well received. In September 1994, the authority decided to switch to a semi-active Type II transponder to avoid the problems associated with the smart card. Tag options include an LED indicator and audio buzzer (10,38).
Table 7. Comparison of ETC Facilities (38-40).
Project Transponder No. No. Lanes No. Tags Opened Plazas
California FasTrak Type II 25 230 18,000 Second phase: Semi-Active (expected) July 1996
Illinois I-Pass Type III 22 196 12,000 December 1994 Active
Virginia FasToll* Type II 30 88 27,000 April 1996 Semi-Active
* Includes both Dulles Greenway and Dulles Tollroad
The toll authority is conducting a unique pilot program with the South Coast Plaza shopping mall. Vehicles equipped with transponders receive preferred parking at the mall. Additionally, the mall sends special discounts to persons using the preferred parking. An agreement was reached with the vendor to reintroduce the smart card-based Type III when smart cards gain substantial acceptance in commercial applications (38).
Illinois I-Pass
A Type III transponder is used by the Illinois State Toll Highway Authority in metropolitan Chicago. This device includes a driver interface consisting of an LCD display, audio alarm, and keypad (9). Motorists who acquire a transponder go to either a designated lane at the toll facility or service center to prepay a set amount of tolls. While in the toll lane, the agent can load the account value on to the transponder via a radio signal so it does not have to be taken out of the vehicle. The transponder can function as an electronic purse, allowing consumers to maintain accounts (decentralized accounting), or in a prepaid account function (centralized accounting). At approximately ½ mile upstream from the toll facility, the maximum toll possible is broadcast to the transponder to determine if the account has sufficient funds. If no account for that toll authority has been established, there are insufficient funds, or the credit card has expired, an audio alarm sounds and an “insufficient funds” message is displayed on the LCD. If the account number is recognized and sufficient funds have been prepaid, the transaction occurs and the driver receives a “fare paid” confirmation message. The LCD is also used to signal the driver when the battery level is low and
H-22 the four AA batteries need replacing. The past 150 transactions may be stored in the transponder. To obtain a printout of the transactions, the driver must go to a service center (9,41).
The transponder has the ability to keep track of 18 separate accounts, so only the act of setting up each account and pre-paying a certain value is required to use the transponder in other systems. The user can check the balance on each account by using the keypad to scroll through each account. While the multi-agency concept is still in the planning phase, the transponder already is equipped to perform the needed accounting and transactions for separate accounts (9). A smart-card based transponder has been developed and tested, but the current consumer demand for smart cards does not yet warrant product introduction. The communication with the transceiver would occur in the same manner as the current Type III, but the monetary value, processing capabilities, and memory storage would be located in the removable card (42). Thus, the smart card-based transponder would not replace the current device, it would only be offered as an option to consumers who found the card more convenient. Using the smart card’s file structure, it may be possible to access a single prepaid balance to pay tolls to any authority. Thus, the user would not have to maintain a prepaid balance in each account and payment would occur in electronic purse format (9,41,42).
Virginia FasToll
The Virginia FasToll system consists of the Dulles Tollroad, which connects to the Dulles Greenway, and a separate toll bridge. The Dulles Tollroad is a publicly owned facility while the Greenway is privately owned. The two facilities link the Dulles International Airport to Washington, D.C., and Leesberg, Virginia, respectively (43) and share a common ETC system. Facility operation is administered by FasToll, a private contractor, which reimburses each system for the tolls purchased via ETC. Therefore, a single user account can be used on each of the three facilities. FasToll uses a Type II semi-active transponder; LED’s or audio warnings are not incorporated into the tag at this time.
Although the system is an open tollroad, with a fixed fee charged at entry points, a read/write Type II transponder was chosen. The decision to use Type II is based on the desire for future incorporation with the Interagency Group (IAG) of ETC toll facilities established in the Northeast. A number of these facilities in New York, Pennsylvania and New Jersey may require read/write capability for payment. The vendor will release a smart card-based transponder early next year which will be compatible with the current FasToll readers (40). Marketing strategy and product cost information were not available at the writing of this paper.
Summary
A Type III transponder is currently operational on only one facility in the United States; the Illinois I-Pass. The device was chosen due its ability to interact with the driver and allow the user to maintain his/her own account balance. A Type III incorporating a smart card was introduced in California, but failed due to technical problems and the lack of card usage in other non-toll applications. This failure is likely to cause other toll authorities and vendors to avoid introducing the smart card interface without longer battery life and increased public demand. Until the smart card gains wider commercial acceptance, it is unlikely that toll authorities, consumers, or vendors
H-23 will have an interest in the product (38). However, the Type II’s used at California FasTrak and FasToll have designed the system for built-in compatibility. This means that the infrastructure is in place to accept Type III tags with smart cards eventually (38,40). Systems without this capability will have a more difficult time phasing in more advanced transponders.
Even without the smart card interface and electronic purse capability, a Type III transponder can manage multiple accounts (up to 18 in the I-Pass project), but the user has to maintain a prepaid balance in each account. A conventional Type III can also provide traffic information and records all transactions for receipt purposes. It’s main limitation, for the purposes of this paper, is that it is not practical for person-based applications, such as transit, due to its large size (5).
Technical Issues
Standards
To provide the framework for a compatible system, ETC standards are being developed from several sources to define the uplink and downlink RF signal and system components. ITS America is drafting a proposal to define the overall requirements for interoperability among ETC facilities. This activity is being undertaken by the Electronic Fee Payment Subcommittee of the Standards and Protocols Committee (6). On an international level, ISO Technical Committee 204 is developing standards for electronic payment and tolls (Working Group 5) and dedicated short range communication (Working Group 15). Other organizations developing standards include: American Society for Testing and Materials (ASTM), American National Standard Institute (ANSI), The Institute for Electrical and Electronics Engineers (IEEE) and The Society of Automotive Engineers (SAE). Standards are also being drafted by individual states (California Title 21) and Interagency Groups (2,6,11).
It is important to recognize that many de-facto or industry standards already exist and will shape the standards writing process, since ETC vendors are represented on the technical committees. Imposing standards too early in a developing industry may also hamper development and stifle creativity. Each vendor may have patents on its equipment which it does not wish to share with other vendors if it becomes the standard. Additionally, a vendor does not want a new standard to make their equipment obsolete (2). It is for these reasons that establishing ETC standards is a long, difficult process requiring a significant level of compromise among vendors.
Active and Semi-Active Transponders
Depending on the tag manufacturer, smart card-based transponders will be either active or semi-active. With an active power source, the transponder contains a transmitter to broadcast a response signal to the reader and can be mounted at any orientation. The active transponder is powered by a connection to the vehicle’s power source or batteries. These batteries have an average life exceeding one year (9). In the semi-active configuration, the transponder is “woken up” by a signal from the reader and the signal is reflected off the tag back to the reader using modulated backscatter. The power source for semi-active tags is generally a lithium battery with a service life of five to ten years (2). Generally, ETC vendors manufacture either a semi-active tag or an active tag, but not both. Thus, ETC systems using active technology, such as Illinois I-Pass, and those
H-24 using semi-active tags, such as Virginia FasToll, are not compatible due to differences in communication methods. Information on semi-active and active tag performance is often disseminated by manufacturers promoting the benefits of their respective configuration over other competitors, so it is difficult to objectively determine which method is optimal.
Automatic Replenishment
Since a Type III transponder stores value itself and not in an account in the toll authority’s database, the user is responsible for seeing the account balance is always sufficient. When the account value is kept in the agency’s database, the user signs an agreement that if the account reaches a minimum value, say $10.00, the balance is increased to a maximum amount, for example, $40.00. The transaction occurs by debiting a bank account or charging a credit card. Without automatic replenishment, an advanced interrogation transceiver is installed to determine if the Type III has enough money within the account. The transceiver must be located far enough in advance to allow the driver to change lanes to a manual booth if the account funds are insufficient. The lack of automatic replenishment also means that manual toll booths and service centers must be equipped to allow users to increase the account balance on the transponder.
Driver Distraction
A transponder with a driver interface requires the driver to look away from the road to read the message on the LCD, insert the card, or use the keypad. A transponder with each of these features is shown in Figure 1. Distraction may be an important safety concern if the transponder is used to give traffic information or route guidance (44). Additionally, the driver may forget to insert a smart card into the transponder before entering the ETC facility. Reaching for the card in a wallet or purse is another activity which takes the driver’s attention off the road. This may not be crucial in parking applications, but it may be a primary concern on non-stop toll lanes. Therefore, any Type III design must take into account driver distractions and users forgetting to insert the card. Audio transmissions may help reduce the requirement to look at the LCD. Perhaps a warning buzzer similar to the seat belt warning, could be sounded as a reminder to insert the card as the driver starts the car.
Figure 1. Amtech’s Type III Transponder with LCD, Keypad, and Smart Card Interface (45).
H-25 Economic Issues
Transponder Cost
The cost of the transponder may be borne by the toll authority or by the user. In many ETC systems, the authority owns the transponder and charges the user a refundable deposit to use the device. This deposit usually ranges from $15.00 to $40.00 (41,46). Type I transponders occupy the low end of the scale while Type III’s are in the upper range. The higher cost may not be justifiable to the commuter who finds the automatic debiting in a toll authority account just as convenient. With direct replenishment, little or no contact with the toll authority is required once the tag has been purchased. The higher cost may also not be justified to the toll operator since the processing of tag sales and accounts may represent a very small portion of the total transaction amounts (46).
Decentralized Accounting
Due to the deposit required for the tag, users tend to keep the tags and use them for long periods of time. Similar to smart cards, toll authority cost savings in ETC may be realized through reduced maintenance, coin and cash processing and labor costs (11). Since the Type III holds monetary value and performs the transaction, the accounting functions may become decentralized. In a decentralized accounting system, calculation of the toll amount, verification of sufficient funds, adjusting the account balance, and notifying the driver are performed by the transponder and not the toll authority’s computer database. Decentralized accounting is estimated to reduce the processing requirements of the roadside system by 30 percent (42). A second advantage is that the cost of sending monthly statements could be eliminated. However, in some cases the toll authority charges a monthly fee for this service (46). Additionally, the system cannot be completely decentralized because the toll road operator needs data for traffic management purposes, to settle account disputes, and prevent fraud. A second disadvantage is that the operator does not collect interest revenue from pre-paid accounts.
Institutional Issues
Agency and Customer Satisfaction
In the case of transit, smart cards were found to offer distinct advantages to agencies over current AFC methods. However, the benefits of smart cards to toll authorities are not well defined and may not outweigh the cost of implementation. The acceptance of smart card transponders by toll road authorities is largely dependent on the existence of built-in compatibility. Where built-in compatibility is not present, the ETC operator may have a difficult time justifying upgrade costs without any significant increases in vehicle throughput, security, or reliability. Therefore, there may be little or no incentive to replace tags for each vehicle. For example, an ETC system with read-only tags and automatic account replenishment is very efficient and requires little or no interaction with the user once the tag has been purchased. Thus, due to high customer and toll authority satisfaction with the current system there may be little motivation to switch to more advanced technology (46).
H-26 Preferred Accounting System
Conversion to a Type III transponder may enable a toll authority to switch from a centralized to a decentralized accounting system. The switch to a decentralized form removes the advantage of collecting revenue in prepaid format. The interest revenue, or ‘float’ from prepaid or unused account balances may be beneficial to toll operations (46). Additionally, the toll operator may need to record transactions in a centralized database for audit, traffic management and customer service purposes. In either accounting scheme, the toll authority may wish to contract the revenue collection function to a clearinghouse or maintain control through the separate accounts capabilities of the smart card. It has yet to be determined is a decentralized accounting system offers cost savings over a centralized accounting system.
Interagency Groups
Interagency Groups (IAG) were formed in the Northeast and in California to enable regional toll authorities to select interoperable technology (2). The results of IAG agreements were increased market penetration and use of ETC facilities, while reducing overall costs to member authorities. The IAG formed by the toll authorities in New York, New Jersey and Pennsylvania, named E-Z Pass, drafted standards for transponder design, transaction reliability, and allowable vehicle speeds at toll plazas. The IAG also explored the creation of a regional clearinghouse to act as the guarantor of toll payments to the members, perform all the processing tasks required to maintain customer accounts, distribute tags, and market the system (2). IAG are important because any move to introduce a different transponder type would have to be agreed upon by all members. Also, the responsibilities of the regional clearinghouse may be drastically different if the change to a decentralized form of accounting is made.
H-27 CASE STUDY: SMART CARD IMPLEMENTATION IN HOUSTON, TEXAS
The purpose of this section is apply the research findings to a hypothetical situation in which a transit and toll agency wish to explore smart card implementation. The City of Houston is chosen as the location because it has not yet begun to test smart cards on its transit system. Additionally, it has an existing ETC system operated by Harris County Toll Road Authority (HCTRA). The hypothetical situation is described as follows: Houston METRO has sponsored a preliminary study on implementation concepts for smart cards on its bus system, and subsequently with other modes of regional transportation. HCTRA requested that the study also provide strategies for including toll collection as one of these modes. The proposal stipulates that three alternatives be identified. Each alternative should be written in a conceptual form describing the implementation and operation of the system. The following sections summarize the results of conceptual designs for this hypothetical proposal. Material for this section results from the authors ideas after consultation with the literature (1,30).
Alternative 1: METRO Operates
In this concept, METRO begins to test smart cards on several bus routes and park-and-ride lots by distributing a few hundred smart cards to interested participants in late 1997. The field operational test is conducted for several months to determine card reliability and customer reaction. The smart card readers are configured to also accept magnetic stripe cards for infrequent riders and those who prefer the cheaper card option. Once the system receives technical approval, full scale implementation begins on all bus routes in 1998. METRO purchases the cards and card readers from the vendor and distributes them to users at no additional charge to the user. However, to insure that people retain the more expensive cards, $10.00 minimum is required to initially purchase a card. Cards can be purchased at service centers, automatic vending machines, established by METRO. Post-payment options are given to employers who subsidize public transit commutes. The data from smart card users is applied for marketing and planning purposes.
Once the smart cards have become widely used on the bus system, customer surveys are completed to determine demand for card usage in on HCTRA facilities early in the next century. Since a portion of commute trips are made by traveling on a toll facility and then to a park-and-ride bus facility, it is determined that a segment of commuters would pay slighter more for the added convenience of a uniform mode of payment. METRO and HCTRA establish a set of operational agreements over card ownership, data exchange, and account reconciliation. Additionally, the ETC vendor signs a contract to provide a set number of transponders initially for testing and marketing purposes. HCTRA does not receive interest revenue from smart card tags since there is no prepaid account and therefore charges a few cents extra for smart card transactions. These tags are given special account numbers so the reader deducts the extra fee. Since automatic replenishment is not offered on the smart cards, there must be an interrogation reader upstream of the toll facility to verify that the smart cards has sufficient value to pay the toll. The existing transponders are retained and smart card-based transponders are provided as an option.
H-28 Alternative 2: Private Contractor Operates
The contractor chosen to test and operate the system for METRO, retains ownership, and oversees full-scale implementation in 1998. Based on the terms of the original agreement, METRO and the contractor agree to a one-year trial in which each receive a portion of the revenue generated from card sales, card value increases, and rides purchased. At the end of the trial, METRO has the optional to renegotiate the agreement, or if terms cannot be agreed upon, it must purchase the AFC equipment at a predetermined price. Since its revenue is dependent on the number of cards in circulation, the contractor assumes full responsibility for card marketing, sales, account administration and providing the infrastructure for convenient card purchase and value increase. The contractor assumes all liability and costs for repair and maintenance of the smart card equipment. Passenger count and origin-destination data are supplied to METRO as part of the agreement.
Once consumer demand to use smart cards for toll payment is established through surveys, the contractor demonstrates a transponder, developed by the current ETC vender, which is compatible with the METRO smart cards and the existing tag readers. After the transponder design has been approved by HCTRA, it becomes available at the existing service center. The contractor provides the necessary staffing to sell and administer both the smart cards and transponders. In this case, to offset the loss in revenue since the account is not prepaid, a small monthly fee is deducted from the smart card on the first time the car enters the facility each month. Similar to the first scenario, an interrogation reader is installed upstream of the toll plaza to verify sufficient funds, and the existing tag system is not affected.
Alternative 3: Acceptance of Bank/Credit Cards
METRO continues to use its current system of magnetic stripe readers until the end of the century. At this time, smart cards have become widely used in banking and credit card applications. Magnetic stripe cards have been almost completely replaced at banks, stores, and service providers by the contact smart cards. Early in the next century METRO conducts an extensive survey which finds that people would like to use their bank cards to pay bus fare. METRO, however, does not have the funding available to purchase a set of new cards and replace the supporting infrastructure. A contractor is hired to test and implement the system, only this time the cards are issued by a third party: banks or credit card companies. Major banks charge users for the cards and provide ATM machines to for card value increase. If credit cards are chosen over bank cards, the credit card company reimburses METRO and bills the users monthly. A transaction fee is charged to METRO for this service. The smart cards issued must give the user two options for payment; a transit application which is set up through METRO, or an electronic purse. The card reader checks for sufficient funds in the transit file, and if no account or sufficient funds exist, the electronic purse is deducted. A slight discount is given for those paying with the transit application, since data can be gathered on the user for planning and marketing purposes. This option is preferred by frequent users or those whose trips are employer subsidized. The electronic purse option is preferred by infrequent users, since they don’t have to set up an account before riding.
Customer surveys indicate to HCTRA that a segment of customers will pay the increased fee for transponders which accept bank cards. The current ETC vendor agrees to provide smart card- based transponders, purchased by HCTRA. Similar to METRO, the card will have an optional toll
H-29 application on the card which can be set up at HCTRA when the person purchases the new transponder. As with the previous scenarios, an advanced interrogation signal is required and the existing tag system remains in place. During the transaction, the transceiver recognizes if a prepaid account exists on the card and deducts the toll from the account balance. However, if no account exists or funds are insufficient, the toll is deducted from the card’s electronic purse. Credit cards may be accepted through a similar agreement to the one with METRO. Users pay a slightly higher toll because HCTRA no longer receives interest revenue or ‘float’ from the new accounts.
Comparison of Alternatives
The primary advantage of Alternative 1 is that METRO retains full control of its revenue collection system. However, private industry may be better equipped to install and operate the equipment in the long run (30). Additionally, METRO is responsible for the entire purchase and maintenance costs of the system. Finally, it may be difficult for METRO and HCTRA to agree on the card ownership and customer service responsibilities that results in a convenient system from the user’s perspective. Customers using both toll and transit application on the card do not want to be referred back and forth between agencies to solve their problems.
The second alternative may be advantageous because the expertise of the private sector is utilized and the purchase cost may be shared with the contractor in exchange for a portion of revenue from card sales and transit fare. It may be more cost-effective to contract out the administrative and customer service responsibilities, and thus reduce agency workload. The primary disadvantage of this arrangement is that METRO must provide significant oversight to ensure that revenue is collected and distributed properly, that customers needs are met at service centers or vending machines, and that marketing plans are carried out properly. By paying the contractor based on card sales and ridership, this may encourage strategic marketing and responsive customer service to maximize profits. To introduce the cards for toll payment, the contractor would have to negotiate a lower cost per transaction than HCTRA currently pays, and charge a small additional fee to replace lost revenue from prepaid accounts.
The third alternative may be ideal because METRO does not have to purchase the cards, administer, or oversee revenue collection activities. The supporting infrastructure is already in place in the form of ATM machines, and customer service centers are located at any local bank. This may provide a more convenient and extensive network for card purchase and value increase. In the case of credit card acceptance, METRO may be able to pay a transaction fee lower than the current cost to collect and process transactions. Additionally, the electronic purse option gives METRO the ability to accept bank cards (credit cards) from tourists, or otherwise infrequent users.
H-30 CONCLUSIONS
The results of this research confirm that a smart card-based transponder is currently the most feasible way to meet the person-based and vehicle-based requirements of a common form of payment (5). Based on this finding, several applications of smart card-based transponders were presented in an overview of the European ADEPT and GAUDI projects. Applications included: providing traffic information or parking information to the driver, congestion pricing, IP systems, and vehicle access control. U.S. transit systems were found to be at the early implementation stage of smart cards. International standards have been completed for contact smart cards while proximity card standards are nearing completion.
Toll facilities in the U.S. do not currently use smart card-based transponders, although these products have been developed by nearly every major manufacturer. The primary reason that the products have not been introduced further is that they do not offer the distinct set of advantages in increased throughput and reduced maintenance found in transit. Current ETC systems are very efficient, reliable and satisfactory from both the user and toll operator perspectives. There may be significant cost disadvantages resulting from the loss of prepaid accounts and direct replenishment. A nationwide standard for ETC system design is not likely to be completed in the near future due to the involvement of manufacturers wishing to prevent their equipment from becoming obsolete. However, ETC standards are being drafted by a host of organizations and have been approved at the state and interagency level. The smart card-based transponder may offer a driver interface allowing two-way communication with the roadside. Safety issues should be considered since a driver’s attention is directed away from the roadway to the transponder when inserting the smart card or receiving information.
Smart cards are currently being implemented in transit systems because they offer immediate benefits to the agency. In contrast, at existing ETC facilities the immediate benefits to the toll authority providing an optional smart card-based transponders are offered to the user through increased convenience. This was found to be the primary reason that implementation in transit systems is occurring at a rapid rate, while relatively non-existent in toll applications. Analysis of potential and immediate benefits is show in Table 8.
Motivation to Implement Smart Card Systems
As discussed above, transit agencies and toll operators have different motivations for implementing smart card systems. The transit agency’s motivation to implement smart cards is largely due to projected cost savings and increased revenue. The smart card payment medium has proven superiority over magnetic stripe cards, generally the existing media for AFC systems. Conversely, a smart card-based transponder has not exhibited proven superiority over existing toll tag systems, based on cost savings and increased revenue. The existence of prepaid accounts is attractive to the toll operator because of interest revenue generated. Additionally, direct replenishment does not require an upstream transceiver to verify account balance nor any action by the user to increase account value. Benefits may be realized if a decentralized accounting system were cheaper due to simplifying the reader and data processing equipment. Additional sources of motivation were also identified as a desire to use transponders for traffic management, or to
H-31 communicate information about the vehicle or cargo to the toll authority for commercial vehicles. If a weigh station is located along the facility, the smart card may also be used to identify the driver, company, and truck cargo (17). Thus, in transit the primary motivation for smart cards is cost savings, whereas, for toll collection, it may be enhancing user services for those willing to pay the additional cost.
Table 8. Summary of Conclusions.
Application Immediate Effect Potential Benefits
Transit C reduced cash and coin handling C flexible fares, distance-based pricing C reduced fraud C discounts to frequent or multi-modal users C increased passenger throughput C ridership data available for marketing and C increased card life, reduced maintenance planning purposes
Toll Collection C may reduce costs with less account C improved commercial vehicle processing administration and supporting at weigh stations and international border infrastructure crossings C no increases in vehicle throughput C decentralized accounting system C anonymous, highly secure transactions C electronic purse application may allow C allows multiple persons to use same tag multi-toll system use (vehicle) with different cards
Integrated Payment C allows convenient transfer of vehicle- C ability to offer discounts for transfers from based modes to person-based modes vehicle to bus (and vice versa) C provides a receipt containing transaction C acceptance of electronic purse form of history for records keeping payment may allow universal use of card C may allow bank or credit card company to manage system at a lower cost to agencies
Benefits of an Integrated Payment System to Other Modes
The potential advantages of an integrated payment system can be categorized by improvements in user services and cost savings to the member agencies. The elimination of exact change requirements, transfer slips, multiple transit passes, and multiple toll accounts would provide a more seamless transfer among modes for the user. Potential combinations of ETC and AFC systems during a single trip include; going from a park-and-ride facility to a bus, going from a toll road to a train station. Other advantages may be realized from commercial vehicles sent on long trips. In an open system, a single card could be used to pay for all items (tolls, gas, meals, lodging, parking) related to cross-country trips in the trucking industry, and act as a receipt for accounting purposes. Similarly, for business trips, a single card could be used to rent a car, and pay for parking fees, meals, and lodging. Increases in passenger throughput, reduction in cash/coin processing and maintenance may also be realized from smart card applications for parking facilities, ferry operators, and the taxi cab industry. The ferry operator would benefit because a smart card-based transponder could automatically identify, and charge entering vehicles, based on vehicle classification or cargo. The taxi cab industry would find real benefits in increased security, since the driver would not have cash.
H-32 RECOMMENDATIONS
The findings of this research indicate that a smart card-based transponder is required to meet both the person-based and vehicle-based requirements defined by previous studies (5). The technology is available and has been tested in other countries around the world. The United States is in the midst of an incredible transition to smart cards which will soon influence all facets of fare collection for transportation services. It is likely that smart card AFC systems will be fully operational in all major U.S. cities within the next ten years. The introduction of proximity smart cards has proved to be cost effective and has been well-received by participants in demonstration projects. The benefits of smart card-based transponders are not well-defined in systems which currently operate with passive tags. The current satisfaction levels with a current read-only tag system may make any conversion to a Type III transponder unlikely in the near future. Consumer demand for smart cards and increased convenience may have to be the driving force for any type of change. However, systems currently using less sophisticated tags may convert to smart cards with relative ease if the ETC vendor has built-in compatibility for upgrades. Subsequent recommendations are categorized by the technical, economic, and institutional requirements which should be considered to optimize an integrated AFC and ETC system. These recommendations are summarized in Table 9.
Table 9. Recommendations for Smart Card Integration in Transit and Toll Applications.
Area Recommendations
Technical C built-in compatibility Specifications C hybrid configuration C driver interface to provide a two-way communication link C flexible payment options: electronic purse and/or automatic debiting
Economic C cost savings over current fare/toll collection system Conditions C consumer demand C discounts for multi-modal travel C open system with both centralized and decentralized forms of accounting
Institutional C establishment of a supporting infrastructure Requirements C agreement on compatible technology C agreement on ownership of cards and data C determination of revenue collection and distribution methods
Technical Specifications
The technical specifications pertaining to operating frequency, data transmission rate, and memory for an integrated smart card IP system have been studied extensively in previous work (5), and are therefore not presented in this report. The card requirements are virtually identical for AFC and ETC in the case that the transponder acts as a card reader, powering the card processor, and sending communication signals to the transceiver. The first technical requirement defined by this
H-33 research is built-in compatibility. Systems currently not using smart cards in either AFC or ETC systems should have the ability to phase in smart cards without affecting or changing the existing systems. Without the ability to phase in more advanced transponders, to operate concurrent with existing tags, it is unlikely that any change will occur without measurable benefits to the toll operator. A second technical requirement is the flexibility offered from a hybrid card. A hybrid card can have a combination of magnetic stripe, contact, and proximity communication capabilities to serve both commercial and transportation uses.
A third technical specification is the driver interface. The driver interface should be configured to provide a two-way communication link between the driver and roadside. The driver interface may include LED’s or a buzzer to provide confirmation of the toll transaction and a LCD to provide account balance information. The two-way communication link may be initially developed for commercial vehicles at weigh stations and border crossings. The smart card will carry information about the driver, cargo, company and destination and allow automated processing through customs. The driver interface also has the capability of providing traffic information and parking information. However, as the possible number of functions grows, the driver’s attention is diverted from the roadway. Appropriate design features should minimize driver distraction by using audio and/or brief short messages on the LCD. A fourth technical specification is flexible payment options. The card should function as an electronic purse and allow multiple applications. The user would have the option pay for the transportation service via a prepaid account on the card (and may receive a discount to do so), or if account balance was insufficient, use the electronic purse function. This would be required for nationwide acceptance on toll roads so that the driver does not have to stop and start an account in each new system.
Economic Justification
Transit agencies implementing smart card systems anticipate long-term cost savings though reduced cash/coin processing costs and reduced maintenance. Additionally, passenger throughput can be increased along with easier access for the disabled. Long-term cost savings and increases in passenger throughput may not be anticipated for toll operators. Therefore another factor must influence development; consumer demand. The failure of the smart card in the Foothill Transportation Corridor is an indicator of the need for an existing infrastructure before people will want to use smart cards. Without the convenience and ability to use the card in banking, commercial, and other transportation modes, the consumer will see little benefit in a smart card- based transponder. Several ETC facilities have recognized that the smart card infrastructure will be in place in the near future and have built-in compatibility to enable a smooth transition. In summary, the smart card-based transponder will be attractive to those willing to pay for the convenience; but not to those satisfied with a toll authority account automatically replenished by their bank account or credit card. The smart card should be the tool used by agencies to offer incentives for multi-modal travel and frequent ridership. These incentives include discounts for; transfers between modes, employer- subsidized trips, and decreased fares with increased number of rides purchased. The second mode on a trip can be discounted because the card can recognize that a transfer is taking place due to the proximate times of the transactions. Employers will prefer the smart card because they will only be charged for actual trips taken and do not have to provide monthly or weekly passes that may go unused. Additionally, they can evaluate the number of employees taking advantage of the subsidy.
H-34 A flexible payment medium consisting of both an electronic purse and prepaid transit account should be provided on a single card. The electronic purse will be preferred by infrequent users while the transit account will be used by frequent riders. The transit account should receive discounted fare because it offers the advantage of a prepaid system and gives the agency detailed passenger data for marketing and planning purposes.
Institutional Requirements
A range of institutional agreements are needed to achieve an integrated payment system. Preliminary decisions must determine the method of purchase and operation of supporting infrastructure, agreement on compatible technology, card ownership, and liability. The preferred infrastructure may consist of a combination of vending machines, phone lines, service centers, or E- mail. The operation of the infrastructure should depend on the level of available funding and level of control over revenue collection that the agency wishes to maintain. Compatible technology is crucial where suburban or smaller transit authorities wish to phase in smart cards once they are established by the lead agency. Card ownership terms must define protocol for card sales, data exchange, data access, and account reconciliation.
Three concepts for smart card development were identified in the Houston case study; a closed system operated by the lead agency, a closed system operated exclusively by a private entity, or an open system in which bank or credit cards are accepted. There are a number of advantages and disadvantages to each system which were noted in the previous sections. The Ventura County system is an example of a closed system operated by a lead agency while New York and Seattle are investigating contracting revenue collection to private entities. The general use smart cards issued by banks in Atlanta this summer, and the acceptance of credit cards in Phoenix (1) will provide insight as to the benefits of open system arrangements. Transit systems such as Houston METRO and toll authorities such as HCTRA should continue to monitor these developments to determine which arrangement will be most cost-effective and responsive to consumer needs.
H-35 ACKNOWLEDGMENTS
This paper was prepared for CVEN 677, Advanced Surface Transportation Systems, a graduate course in Transportation Engineering at Texas A&M University. The author extends thanks to the course instructor, Dr. Conrad Dudek, for guidance on developing the topic and contents of this paper. Sandra Mantey served as the administrative assistant and was instrumental in course organization and producing this compendium. The experience gained from this course would not be possible without the mentors who volunteered their time to participate in the program. The author expresses gratitude to Walter Dunn, Ginger Gherardi, Les Jacobson, Jack Kay, Colin Rayman and Thomas Werner. Special thanks is given to author’s mentor, Colin Rayman, who reviewed this paper and offered suggestions for improvement. The following professionals are acknowledged for taking time to respond to telephone interviews, provide additional contact persons, and send information on this subject.
Ramon Ambromovich Washington Metropolitan Area Transit Authority Dennis Bennett Lockheed/Martin Gary Butts Amtech Candice Carlson King County Department of Transportation Michael Dinning Volpe Center Mark Figura AT/Comm Ginger Gherardi Ventura County Transportation Commission Paul Manuel Mark IV Industries Joe Simonetti Chicago Transit Authority Carol Schweiger Multisystems, Inc Mike Stretch Harris County Toll Road Authority Carol Zimmerman Battelle
H-36 REFERENCES
1. Fleishman, D. and N. Shaw. “Fare Policies, Structures and Technologies” TCRP Report 10, Transportation Research Board, Washington, DC, 1996.
2. Venable, D. L., R. B. Machemehl and M. A. Euritt. “Electronic Toll Collection Systems” Center for Transportation Research Report #1322-2, Austin, TX, May 1995.
3. Pietryzk, M. C. “Electronic Toll Collection Systems” Transportation Research Board Special Report 242, pp. 464-501, Washington, DC, 1994.
4. Hayes, S. and K. Cabrero. “Generalised and Advanced Urban Debiting Innovations: The GAUDI Project” Traffic Engineering and Control, January 1995.
5. Bushnell, W. R. “Smart Cards for Transit: Multi-Use Remotely Interrogated Stored-Data Cards for Fare and Toll Payment” Report Number FTA-MA-26-0020-95-1, April 1995.
6. Zhang, W., L. N. Spasovic, A. K. Bladikas, L. J. Pignataro, E. Niver and S. Ciszewski “APrimer on Electronic Toll Collection Technologies” presented at the 74th Annual Meeting of the Transportation Research Board, January 22-28, Washington DC, 1995.
7. Cunningham, R. F. “ETTM Equipment Interoperability” Traffic Technology International, 1996 Annual Review.
8. Pietrzyk, M. C. and E. A. Mierzejewski Electronic Toll and Traffic Management (ETTM) Systems, NCHRP Synthesis 194, Transportation Research Board, 1993.
9. AT/Comm Incorporated “The AT/Comm Smart Transponder” Information Packet.
10. A. Tip and L. d’Hont “Reflecting Tomorrow’s Highways Today” Traffic Technology international, 1996 Annual Review.
11. ETTM Task Force “An ETTM Primer for Transportation and Toll Officials” ITS America, March 1995.
12. Smart Card Forum Home Page [http://www.smartcrd.com]
13. Holmstrom, F. R. “Integrated Electronic and Automated Fare Payment Systems” [http://www.fta.gov] 1996.
14. Zoreda, J. L. and J. M. Oton Smart Cards Artech House Inc., Norwood, MA, 1994.
15. Anara, F. “Smart Card Offers Solution for Road Traffic and Parking Management” Traffic Technology International, 1995 Annual Review.
H-37 16. Blythe, P. T. and P. J. Hills “Automatic Debiting and Electronic Payment for Transport- The ADEPT Project”, Traffic Engineering and Control, February 1994.
17. Hedin, J. and J. Sundberg “Automatic Debiting and Electronic Payment for Transport- The ADEPT Project”, Traffic Engineering and Control, March 1994.
18. Clark, D. J., P.T. Blythe, N. Thorpe and A. Rourke “Automatic Debiting and Electronic Payment for Transport- The ADEPT Project” Traffic Engineering and Control, April 1994.
19. Mustafa, M. A. S. and G. A. Giannopoulos “Automatic Debiting and Electronic Payment for Transport- The ADEPT Project”, Traffic Engineering and Control, May 1994.
20. Stathopoulos, A. G., N. Papachristou, C. Mateus and G. Hatoglou “Automatic Debiting and Electronic Payment for Transport- The ADEPT Project”, Traffic Engineering and Control, June 1994.
21. Flynn, B. “Generalised and Advanced Urban Debiting Innovations: The GAUDI Project”, Traffic Engineering and Control, February 1995.
22. Meland, S. “Generalised and Advanced Urban Debiting Innovations: The GAUDI Project”, Traffic Engineering and Control, March 1995.
23. Hayes, S., O. Gascon, J. Crespo, S. Bonora and F. Gazzotti “Generalised and Advanced Urban Debiting Innovations: The GAUDI Project”, Traffic Engineering and Control, June 1995.
24. Chira-Chavala, T. and B. Coifman “Impacts of Smart Cards on Transit Operators” presented at the 75th Annual Meeting of the Transpiration Research Board, January 7-11, 1996, Washington D.C.
25. Telephone Conversation with Joe Simonetti, Chicago Transit Authority, July 2, 1996.
26. Telephone Conversation with Ginger Gherardi, Ventura County Transportation Commission, July 12, 1996.
27. Telephone Conversation with Candace Carlson, King County Metro, July 8, 1996.
28. Telephone Conversation with Ramon Ambromovich, Washington Metro Area Transit Authority, July 9, 1996.
29. Simonetti, J. “Chicago’s Transitional Smart Card Implementation Approach” CardTech/SecurTech Conference Proceedings, May 1996.
30. IBI Group “Regional Fare and Technology Coordination” a feasibility study prepared for King County Metro, Seattle, Washington, January 1996.
31. Ventura County Transportation Commission “Get Smart” Information Brochure, 1996.
H-38 32. Tokitsu, N. “Smart Cards in Electronic Toll Collection Systems” Traffic Technology International, 1995 Annual Review.
33. Card Europe UK “Smart Card Technology Leading to Multi Service Capability” [http://www.gold.net/users/ct96] 1994.
34. Harrop, P. “The Electronic Purse” IEE Review, June 1992.
35. Fisher, R. J. and S. Ricketson “Opportunities for Smart Cards in American Public Transit” Report Number FTA-TTS-30-92-2, 1992.
36. Holmstrom, F. R. “Smart Fare Payment Systems for Public Transit” Technical Brief #10 [http://www.fta.dot.gov], January 1996.
37. Burke, J. L., Jr. “Legal and Regulatory Implications of Advanced Card Programs” CardTech/SecurTech Conference Proceedings, May 1996.
38. Telephone Conversation with Dennis Bennett, Lockheed Information Management Services, July 10, 1996.
39. Electronic Toll Collection Home Page [http://village.ios.com/~mkolb/etc.html]
40. Telephone Conversation with Paul Manuel, Mark IV Industries, July 16, 1996.
41. Telephone Conversation with Mark Figura, AT/Comm Incorporated, July 9, 1996.
42. Brown, R. L. “Intelligent Transponders: A Platform for Enhanced Transportation Functions” Traffic Technology International, 1996 Annual Review.
43. Virginia FasToll Home Page [http://www.fastoll.com]
44. Telephone interview with Gary Butts, Amtech, July 2, 1996.
45. Amtech “The Dynicash System” Information Packet.
46. Personal Interview with Mike Strech, Harris County Toll Road Authority, June 24, 1996.
47. Federal Transit Administration “Advanced Public Transportation Systems Benefits” Information Packet, March 1996.
48. Newman, D. and B. Barink “Follow the Wavelength” Traffic Technology International, June/July 1996.
49. Nott, G. “Contact-less Chip Cards” Traffic Technology International, 1995 Annual Review.
50. Ognibene, P. “Smart Cards: The Next Generation for ETC”, ETTM Forum, April 1996.
H-39 51. Pietryzk, M. C. and E. A. Mierzejewski “Electronic Toll Collection Systems: The Future is Now” TR News, pp.14-19, November-December 1994.
H-40 Clint Schuckel received his B.S. in Civil Engineering from the University of Michigan in April 1995. While at the University of Michigan, he was employed for 3 summers by King, Ryan and Associates, a civil engineering consultant. From May 1994 to August 1995, Clint was employed in the engineering division of the City of Ann Arbor, Michigan. In August of 1995, he enrolled at Texas A&M University to pursue a M.S. in Civil Engineering and concurrently work as a Graduate Research Assistant for the Texas Transportation Institute. At Texas A&M, Clint serves as the Public Relations Officer of the ITE Student Chapter and as the Volunteer Coordinator of the campus Habitat for Humanity Chapter. His areas of interest include: geometric design and traffic safety.
H-41 THE USE OF THE INTERNET AS AN EFFECTIVE TOOL FOR DISSEMINATING TRAVELER INFORMATION
by
Lee Anne Shull
Professional Mentors Ginger Gherardi Ventura County Transportation Commission
and
Leslie N. Jacobson, P.E. Washington State Department of Transportation
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, Texas
August 1996 SUMMARY
The evolution of the information age has produced a powerful tool for disseminating information to a varied audience. This tool, commonly referred to as the Internet, is growing rapidly in popularity as a valuable information resource. Many transportation agencies are offering pre-trip planning information via the Internet. Information about real-time traffic congestion, incidents on major highways, updates on construction activities, bus and rail schedules, transit routing, and fare information are a few examples of the types of information that transportation agencies are providing to the public via the Internet. The use of the Internet as an effective tool for disseminating traveler information depends on the provider’s ability to offer relevant, accurate, and timely information to the user.
The objectives of this research project were to first identify examples of the use of the Internet for conveying multi-modal and multi-agency traveler information. Five Internet sites maintained by transportation agencies in the states of Washington, California, Georgia, and Minnesota were identified as case studies. The providers of the transportation information were then surveyed to identify the difficulties (from the perspective of the provider) in conveying static, real- time, and interactive information to the public via the Internet.
The perspective of the user was obtained from a literature review, focus group study of accessibility, and navigation through each site. Providers must consider the needs of the user when designing an effective Web site for disseminating traveler information. Providing the right information in a convenient form at the appropriate time will help users of the information services make smarter choices about when, where, and how to travel.
Both the providers of the information services and the users of these services are recognizing numerous benefits of disseminating transportation information via the Internet. The information is made available to the public anytime during the day or night at a relatively low cost to the providing agency. The public can directly obtain the desired information with little to no assistance from the providing agency staff. Although many agencies report an increase in E-mail “traffic” from the public, these information providers are recognizing that it is easier and more efficient to answer similar E-mail requests than it is to provide the same information over the telephone. The Internet also shows great potential to reach a varied audience that may not already be exposed to transit information. Many users of the Internet case study sites indicate that they would now consider alternatives to their usual single-occupant vehicle commute.
Many transportation agencies are eager to provide information on the Internet about transportation within their city. Much can be learned from those presently utilizing this medium to reach the public. After considering both the perspective of the provider and the user, recommendations were made on ways to improve the dissemination of transportation information to the public via the Internet. These recommendations were developed to assist agencies in planning, designing, and evaluating the effective use of the Internet for this purpose.
I-ii TABLE OF CONTENTS
INTRODUCTION ...... I-1 Problem Statement ...... I-1 Research Objectives ...... I-1 Study Approach and Scope ...... I-2 Organization of Report ...... I-3
WHAT IS AN ATIS? ...... I-4 The Evolution of the Internet ...... I-4 The Internet as an ATIS ...... I-5
EXAMPLES OF THE USE OF THE INTERNET AS AN ADVANCED TRAVELER INFORMATION SYSTEM ...... I-6 Riderlink of the Seattle Area ...... I-6 Objectives ...... I-6 Information Services ...... I-7 Measures of Effectiveness ...... I-8 Future Enhancements ...... I-10 Go Ventura of Ventura County, California ...... I-10 Objectives ...... I-10 Information Services ...... I-11 Measures of Effectiveness ...... I-11 Future Enhancements ...... I-13 Washington State Department of Transportation Home Page - Northwest Region ...... I-13 Objectives ...... I-13 Information Services ...... I-13 Measures of Effectiveness...... I-15 Future Enhancements ...... I-16 Traveler Information Showcase of Atlanta, Georgia ...... I-16 Objectives ...... I-16 Information Services ...... I-16 Measures of Effectiveness ...... I-17 Travlink of Minnesota ...... I-17 Objectives ...... I-17 Information Services ...... I-17 Measures of Effectiveness ...... I-18 Future Enhancements ...... I-18 Summary ...... I-18
THE PERSPECTIVE OF THE PROVIDER ...... I-20 Difficulties in Conveying Information ...... I-20 Maintaining the System ...... I-20 Maintaining Financial Support for the System ...... I-21 Lack of Control Over Final Product ...... I-21
I-iii Lessons Learned ...... I-21 Overall Benefits ...... I-22
THE PERSPECTIVE OF THE USER ...... I-23 User/Traveler Needs and Constraints ...... I-23 The Commuter ...... I-24 Male vs Female ...... I-24 Comprehensive Nature ...... I-25 Focus Group Study of Accessibility ...... I-25 Display of Information ...... I-26 Attention Span ...... I-26 Use of Frames ...... I-27 Speed of Transmission of Information ...... I-27 Weather Information ...... I-28 Information Security and Safety ...... I-28 Summary ...... I-29
WAYS TO IMPROVE THE DISSEMINATION OF TRANSPORTATION INFORMATION TO THE PUBLIC VIA THE INTERNET ...... I-30 Planning Stages ...... I-30 Establish an Advisory Committee ...... I-30 Conduct Surveys and Focus Groups ...... I-30 Develop a Logo or Slogan ...... I-30 Coordinate with the Local Transportation Management Center ...... I-31 Design Stages ...... I-32 Consider Human Factor Expectancy Issues ...... I-32 Categorize Information ...... I-32 Utilize Landmarks ...... I-33 Provide Reliable Links ...... I-33 Incorporate Search and Reset Functions ...... I-34 “Fit-The-Screen” ...... I-34 Provide E-Mail Link ...... I-34 Evaluation Stages ...... I-34 Monitor the Use of the Information Service ...... I-34 Survey Users of the System ...... I-34 Continue to Refine and Improve the System ...... I-37
CONCLUSIONS ...... I-39
ACKNOWLEDGMENTS ...... I-40
REFERENCES ...... I-41
I-iv INTRODUCTION
Over the last decade, the transportation industry has witnessed a variety of applications of advanced technologies. The basic objective of these technologies is to improve the operational efficiency of transportation services. In meeting this basic objective, other societal and community objectives are realized in the reduction of pollutants and motorist stress with decreased congestion.
The field of transportation has also evolved into the information age. In order for the traveling public to make wise choices about the best route, mode, and time for travel, they must be provided the right information at the right time and in the right form. The use of the Internet continues to grow rapidly as a platform for transportation information. The pre-trip planning process has high potential for being facilitated by the myriad of transportation resources available through the Internet. These resources might include traffic congestion and incidents on major highways, updates on construction and road-closings, bus and rail schedules, directions to transit stops, fare information, information on restaurants, hotels and points of interest, and transit routing options.
Problem Statement
Many transportation agencies are eager to reach the public through the Internet. Few know how to utilize this medium effectively as a tool for disseminating traveler information. Much can be learned about the development of an effective site from those agencies presently providing multi- modal and multi-agency transportation information via the Internet. If success tips and lessons learned from the development of these Internet sites are not shared, the use of the Internet as a reliable, efficient, and convenient source of transportation information may be jeopardized.
Research Objectives
The objectives of this research project were to:
1. Identify examples of the use of the Internet for conveying advanced traveler information to facilitate the pre-trip planning process.
2. Identify the difficulties (from the provider’s perspective) in conveying static, real-time, and interactive information to the public via the Internet to influence pre-trip planning. Catalogue theses difficulties and recommend approaches to circumvent these problems.
3. Identify special design considerations from the perspective of the user of the system. Identify human factors issues related to the dissemination of travel information.
4. Recommend ways for a transportation agency to improve the dissemination of transportation information to the public via the Internet.
I-1 Study Approach and Scope
The initial task was to identify examples of the use of the Internet for conveying advanced traveler information to facilitate the pre-trip planning process. Due to the abundance of transportation information available on the Internet, five Internet sites were chosen as case studies. These sites are maintained by various agencies within the following four states: Washington State, California, Georgia, and Minnesota. These sites were chosen to illustrate the variety of ways that multi-modal and multi-agency transportation information is provided on the Internet.
To fulfill the second research objective, the author surveyed the providers of the transportation information Internet sites identified within the initial task. The survey was used to identify the perspective of the provider when utilizing the Internet as a tool for disseminating transportation information. The providers were asked the following questions:
1. Discuss the reasons for initially offering the transportation information services on the Internet. What were the circumstances under which the services were developed? 2. Briefly describe the information services offered on your organization’s Web site. These may include static (e.g., transit schedules), real-time (e.g., current freeway speeds), and/or interactive (information on best routing based on origin and destination of user). 3. What objectives did your organization hope to meet with the information services? 4. During the initial development of your organization’s Internet information services, what traveler-needs were identified? 5. Has your organization attempted to measure the effectiveness of its Internet information services? What did you measure and how did you measure the effectiveness? Please discuss customer feedback and surveys of the public-at-large or of the Internet customers. 6. What changes in the number of system users (“hits”) do you notice during inclement weather? 7. What difficulties has your organization encountered in conveying static, real-time, and interactive information to the public? 8. What “lessons” has your organization learned in the development of an effective presentation of transportation information via the Internet? Please address static, real-time, and interactive presentations of information. 9. What enhancements is your organization considering in order to improve the presentation of traveler information on the Internet? 10. What do you see as the benefits of providing the information services?
In satisfying the third research objective, the perspective of the user was identified through the following activities:
C A literature review to identify current research on the development of effective Advanced Traveler Information Systems (ATIS); user needs and constraints; characteristics of the commuter; and the propensity of the commuter to alter travel time, mode, or route; C A focus group study of potential users of the Internet sites to identify accessibility of the site; and
C An evaluation of the Internet sites to identify recommendations for improving the dissemination of transportation information to the public via the Internet.
I-2 Based on the findings of the first three research objectives, the final research objective was accomplished by presenting recommendations for improving the presentation of transportation information on the Internet. These recommendations will assist agencies in developing and utilizing their Internet site as an effective tool for disseminating transportation information.
Organization of Report
The report begins with a definition of an advanced traveler information system. Numerous methods used to disseminate traveler information to the public will introduce the potential for the Internet to meet this objective. Following a brief history of the Internet, overviews of Internet sites offering multi-modal and multi-agency transportation information will be provided. A discussion of the perspective of the provider will highlight the difficulties and the lessons learned when providing transportation information to the public via the Internet.
To introduce the perspective of the user, the needs of the user/customer/consumer/public will be addressed as they pertain to the development of an effective Internet site. Comments from focus group participants and the author’s assessment will portray the perspective of the user when accessing the Internet site case studies. Ideas for enhancing both content and style of the Internet presentation will follow. The report will conclude with recommendations to assist agencies in utilizing the Internet as an effective tool for disseminating transportation information.
Internet sites are referenced throughout the report by the uniform resource locator (URL) address unique to each site. All the URLs presented in the report were accurate at press time. However, changes in Web site addresses are not uncommon. Therefore, if a particular URL does not connect to the desired information, try typing only the portion before the first single slash, and then search the site. For example, if typing the first URL address shown below does not produce a map of Seattle traffic conditions, try the second URL address and then search within the site to find information on the northwest region of the state.
Trial 1: http://www.wsdot.wa.gov/regions/northwest/NWFLOW/default.htm#Anchor Trial 2: http://www.wsdot.wa.gov
I-3 WHAT IS AN ATIS?
ATIS refers to an Advanced Traveler Information System. This term is used to describe systems that provide a variety of transportation information to travelers prior to and during a trip to facilitate pre-trip planning and navigating processes. When the right information is provided at the right time and in the right form, the traveler can make smarter choices about when, where, and how to travel.
Traveler information is presently provided thorough a number of different technologies. For instance, as the host of the Summer 1996 Olympic Games, Atlanta, Georgia provided transportation information to the visiting public through the following technologies (1):
C Information kiosks (with touch-screens); C Wireless, hand-held computers (personal communications devices); C Interactive television in hotel rooms; C Dedicated transportation information channel on cable television; C In-vehicle navigation devices; and C On-line computer services (Internet and bulletin boards).
The Evolution of the Internet
Before one can appreciate the potential of the Internet as a powerful advanced traveler information system, a brief history of the Internet is in order. Since its initial inception over thirty years ago, the Internet has evolved into the information highway of the 90s. The Internet, or ARPANET as it was referred to originally, began as a high-tech research exercise in national security (2). The government needed a means for US authorities to successfully communicate after a nuclear war. Paul Baran of RAND Corporation first brainstormed on the requirements of such a communications system. He recognized that it should not have a central command center that could serve as an obvious enemy target.
The initial benefits of such a system were recognized with the convenient transfer of data on dedicated high-speed transmission lines. To enhance the ruggedness of the system, data was transported independently on available nodes throughout a decentralized network. This allowed the transfer of information in lieu of an entire portion of the system being rendered inoperable due to some “foreign” attack.
The RAND Corporation, Massachusetts Institute of Technology, and University of California Los Angeles convinced the Pentagon’s Advanced Research Projects Agency (ARPA) to sponsor research in this area. The ARPANET originally provided a means for researchers and scientists to share one another’s rare computer facilities by long-distance. However, the computer-sharing network quickly became a dedicated, high-speed, federally subsidized electronic post-office, servicing news and personal messages (2).
A “Network Control Protocol” (NCP, later superseded by TCP/IP) was established to provide a standard for communication. This protocol was used by other networks to link to the ARPANET
I-4 as early as 1977. The concept and uses of the Internet continued to expand reaching wider are more varied markets and audiences. From its original base in military and research institutions, access to the Internet has grown to include many elementary and high schools, as well as public libraries and commercial businesses.
The practicality of the personal computer, developed during the 70s, has undoubtedly shaped today’s culture, both young and old. Children are being exposed to the word of computers at increasingly younger ages. They are learning early of the benefits and resources that computers provide. Many school teachers and university researchers are utilizing the Internet to enhance their teaching curricula and to research current advancements in their respective fields and interest areas.
The Internet as an ATIS
The potential for the use of the Internet to disseminate transportation information is being recognized throughout the world. The Internet is developing into an ideal technology for integrating multi-modal and multi-agency information to produce a more informed traveler. Several features of the Internet make it an ideal medium for providing transportation information to the public:
C The interactive and colorful interface that can be achieved in the design of the layout can be used to draw interest in transit and other alternatives to the ever popular, single-occupant-vehicle (SOV) commute.
C At no added effort or cost, an agency can provide transportation information 24 hours a day. The information is available to people throughout the world from the comfort of their home or office, rather than being limited to certain target audiences and locations due to budgetary constraints.
C Resources of interest to the public can be bookmarked for fast, convenient reference when the information is needed. (The "bookmark" feature, available through most browsers such as Netscape, stores the uniform resource locator (URL) address of the site requested so that direct access is achieved without the need to search for or type the address.)
C Providers of the information can easily monitor the interest in and demand for the information provided on the World Wide Web (Web) site by recording the addresses of the requestors. User statistics can be developed based on assumptions drawn from these addresses (i.e., "...tamu.edu" indicates that the requestor is from the educational institution of Texas A&M University).
I-5 EXAMPLES OF THE USE OF THE INTERNET AS AN ADVANCED TRAVELER INFORMATION SYSTEM
The features and convenience of the Internet have contributed to its distinction as a valuable information source. Commercial entities are quickly working to establish a presence on the information highway to market their services and to establish a communication link between their customers. The public benefits by being able to:
C Browse through the products offered (i.e, search for a certain Compact Disc by a certain artist from BMG Music Services at the Internet site http://www.bmgmusicservice.com/); C Identify an Ohioan with the same last name for preparing genealogical records; C Find a good recipe for Red Beans and Rice as recommended by a New Orleans chef; or C Offer a script suggestion to the producer of their favorite television show.
With the growing popularity of the Internet, several public transportation agencies have recognized the potential for the Internet as an advanced traveler information system. This chapter highlights examples around the nation where transportation information is provided on the Internet. An explanation of the objectives for each program will be followed by descriptions of the information services provided on the Web sites (home pages). Methods used to measure the effectiveness of the site will then be disclosed. Future enhancements planned to improve the presentation of traveler information on the Internet will also be discussed.
Riderlink of the Seattle Area http://transit.metrokc.gov
The Washington State Legislature adopted the Commute Trip Reduction (CTR) Law in 1991, incorporating it into the State's Clean Air Act (3). The law aims to improve air quality while reducing traffic congestion and fuel consumption (4). The law recommends that jurisdictions set employer goals for reducing SOV commuters and vehicle-miles traveled (VMT) per employee by 15 percent by January 1, 1995, 25 percent by January 1, 1997, and 35 percent by January 1, 1999.
King County Metro Transit (Metro) of the Central Puget Sound area and Overlake Transportation Management Association (TMA) teamed up to offer electronic access to transportation information detailing alternative options to the SOV commute. Overlake TMA is an organization of eight employers, each with over 15,000 employees in a suburban office environment. These companies include Microsoft, Allied Signal, Applied Microsystems, Eddie Bauer, Nintendo, Group Health Cooperative, SAFECO Insurance, and Unigard Insurance (5).
Objectives
The objective of the Riderlink project was to assist these eight large employers in meeting the requirements of the CTR Law by providing easy access to information about transportation alternatives (6). The use of the Internet to meet this basic objective allowed information to be provided to a variety of audiences, including local commuters and those planning vacations to the area.
I-6 Information Services
Riderlink has been on-line since late December 1994, providing information about a broad range of transportation modes (5). These include tips about biking to work, bus schedules and route maps, information about forming vanpools and carpools, and links to ferry schedules. Real-time traffic congestion information and road construction updates are provided via a link to the Washington State Department of Transportation's home page. Metro interacts directly with the public through customer feedback forms, requests for trip planning assistance, and ridematch applications, all available through the Internet. Figure 1 shows the Riderlink home page located at http://transit.metrokc.gov. Clicking on an icon links the user to information about that transportation mode or service.
Figure 1. Riderlink Home page [http://transit.metrokc.gov].
I-7 Measures of Effectiveness
Metro has used a variety of techniques to measure the effectiveness of the information provided on the Internet site. The Riderlink server collects detailed statistics about requests for information and the number of times each page is accessed. Figure 2 indicates the percent of requests made per day between July and November of 1995. Eighty-four percent of the requests occurred during the work week with Friday usage being the lowest. Table 1 shows the features that were accessed the most between July and November of 1995.
Sunday 8% Monday Saturday 18% 8%
Frida y 12% Tuesday 16%
Thursday 17% Wednesday 21%
Figure 2. Riderlink Percent of Requests per Day (July - November 1995) (5).
I-8 Table 1. Riderlink Most Accessed Features (July - November 1995) (5).
Feature Number of Times Accessed Timetable Request Page 6872 Real-Time Freeway Congestion 2584 Bus Directions to Major Destinations 2448 How to Use Riderlink 2152 Biking Resources 1855 Request for Bus Trip Planning 1686 Information About Metro Transit 1636 Bus Fares 1569 Information About the Overlake TMA 1496 Bike Racks on Buses Program 1414 Bus Tunnel Description 1470 News 1466 Metro Phone Numbers 1105 Ride Free Area Description 981 How to ride the bus 891 Riderlink Overview 741 Ridematch Application 582 Diamond Lane Information 570 How to Pay Bus Fare 569 Bus Directions to Transportation Centers 571
Both on-line and off-site surveys have been conducted to measure the ease of use and benefits of the system. Four percent (230) of those (5393) that accessed the home page during a three-week period in October 1995 responded to the on-line survey. Eight-two personal interviews were conducted at two kiosk locations where access was provided to the home page. Overall, the majority of users have indicated that Riderlink is well designed, efficient and informative (5).
I-9 Although printed timetables and telephone information are the primary sources of information, the Internet site presently receives about 400 hits (requests for information) per day with usage growing continuously. Metro recently found success in promoting Riderlink to help alleviate the demand for the printed timetables when they were running low.
Future Enhancements
Based on comments from the users of Riderlink, the following enhancements to the system would allow Riderlink to provide more value to its users (5):
C A text-only version for users of non-graphical browsers. C Additional transportation information for counties adjacent to King County. C Automated trip planning tools where the user can enter an origin and destination and immediately obtain a recommended bus trip. C An on-line system map. C An on-line bike route map.
Metro is currently working with three neighboring transit agencies to expand the geographic region served by Riderlink. Production processes are being improved to reduce the amount of manual labor required to maintain the data. A separate effort is implementing automated trip planning software as a tool for information operators at three agencies in the region. Eventually, the public will have access to those tools through Riderlink (6).
Go Ventura of Ventura County, California http://www.goventura.org
When the Los Angeles Times announced that Ventura County, California had the highest percentage (fifty-four percent) of home computers per household in the nation, the Ventura County Transportation Commission (VCTC) came to the conclusion that the Internet could be useful as a transit marketing tool for the region (7). Utilizing an existing database and software package that provided transit routing information for almost all of Southern California, the VCTC began to offer their services through the Internet.
Objectives
The objectives of the VCTC in establishing a presence on the Internet were primarily twofold. First, the VCTC sought to extend their transportation information services to the potentially Internet-friendly public within the area. This same group was, typically, not exposed to information on transit services within the county and the Southern California area. Secondly, the VCTC recognized the potential for the Internet services to lighten the load on the transit routing phone operators who originally handled all requests for transit routing. The bilingual Dial-A-Route program established the framework for the Internet interactive transit routing program. This program had been in operation for five years, receiving an average of 4000 calls per month.
I-10 Information Services
The "Go Ventura" home page offers a variety of static, interactive, and real-time information services. The static information includes such conveniences as phone numbers for transit providers and services (local bus service, AMTRAK, Metrolink, Greyhound Bus, Airports, PASSPORT monthly bus pass option). The Commission agendas and documents for public review are provided for those interested. Posters and bookmarks, that market both the shift from the SOV commute and the existence of the home page, can be ordered for free directly via the Internet. The multi-modal theme is complete with the presentation of bike maps which functionally classify the routes according to the facility characteristics.
A link is provided to a site sponsored by the Southern California Association of Governments where a Rideshare Commuter Registration form is provided on-line. The form allows Southern California commuters, interested in alternatives to the SOV commute, to record their preferences, needs, and typical commute pattern. Matches can then be made and rides can be shared. Services for seniors and disabled riders are provided on-line with an explanation and application for the Safe Cellphone Program. This program offers a portable cellular telephone, at no cost, to people who drive independently and cannot use the roadside callboxes due to a mobility impairment. Figure 3 shows the Ventura County Transportation Commission home page at http://www.goventura.org.
A unique interactive information service provided through the home page is a transit routing page (8). The user inputs the origin and destination information as well as the day, relative time, itinerary preference (shortest time, fewest transfers, minimal walking), fare category (to determine appropriate discounts), and any special accommodations required (wheelchair, bicycle). The user submits the request and receives a full itinerary for the trip, including all transfer points and fare information. The transfer points are referenced to landmarks in the area to provide additional cues for the traveler. A reference is made at the bottom of the trip itinerary which compares the price of the trip when each transfer is paid for separately, to the price of the trip when the "Smart Passport" (monthly pass) is used.
A link is provided to the Southern California real-time traffic reports provided by Maxwell Laboratories, Inc. for the California Department of Transportation (CALTRANS) (9). Color coded indices relate conditions on the freeway network to various speeds. This information is particularly helpful to those in Ventura County. A number of freeways service a southward travel route. This service allows the public to select the least congested travel path.
Measures of Effectiveness
The VCTC measures the effectiveness of their Internet services in a number of ways. Counters are placed on the various subpages to track the use of the information. This allows the pages to be tailored accordingly. Customer/consumer feedback is invited through an E-mail link on every page. The responses and comments are documented and corrections are made to the database information. Upon receipt of a comment or suggestion, the VCTC programmers respond by sending E-mail back that the suggestion/comment was received, thanking the sender for his/her interest in the program. Most customers are amazed at the responsiveness of a public agency to their concerns, ideas, and opinions. This method of handling customer feedback has shown favorable results,
I-11 evident by the popularity of the home page as the source of Ventura County transportation information. The VCTC has received much positive customer feedback on the transit routing page. Other agencies frequently request permission to provide a link to the VCTC transit routing page so that their customers and employees can access the information service.
Figure 3. Home Page of the Ventura County Transportation Commission [http://www.goventura.org].
I-12 Future Enhancements
The VCTC is actively in the process of developing additional mapping capabilities to enhance the home page. One example is the development of maps that will illustrate the relationship between the transit user’s points of origin and destination to the location of the nearest transit stops. A county wide map is also being developed which will include points of interest and landmarks so that travelers from outside the county can plan automobile or public transit trips ahead of time.
Washington State Department of Transportation Home Page - Northwest Region http://www.wsdot.wa.gov
The Washington State Department of Transportation (WSDOT) presence on the Internet initially began as an experiment. Internet users within WSDOT recognized the growing popularity of the Internet as an information source and began to prepare transportation information pages for each of the six regions of WSDOT. Early success of the site lead to heightened awareness and visibility within WSDOT management. Management is now more willing to allocate time and materials to maintain and enhance the site (10).
Prior to the development of the Web site, real-time traffic information for the Northwest Region was only available to radio and television media and a few large businesses. They were able to access a Traffic Map page through an existing Personal Computer based software system and dial- up phone lines. The eight phone lines could only serve approximately fifty users at the same time.
Objectives
WSDOT sought to provide real-time transportation information to the general public at a very low cost. Upon recognizing the potential to reach a much larger audience via the Internet, the Northwest Region of WSDOT (WSDOT-NW) began developing a site to distribute the Traffic Map to many more users including the general public. Like most providers of transportation information on the Internet, WSDOT hopes that with this service, the traveling public will be able to better plan their trips, adjust their commute times, avoid incidents, and consider alternative modes of transportation.
Information Services
A multitude of information is provided to the public via the WSDOT Internet site. E-mail addresses for all WSDOT employees and state phone numbers are provided for the public via the Internet site to encourage interaction between the users and the providers of the information. WSDOT-NW presents a clickable map of the Seattle Metropolitan Area Traffic Conditions. Different colors along the freeways indicate varying degrees of traffic: Stop and Go, Heavy, Moderate, and Wide Open. Icons of area landmarks such as universities, airports, the Space Needle, sports complexes, and ferry ports provide clickable links to further information. Figure 4 shows the freeway map which is oriented West-up (11).
I-13 Figure 4. Seattle Metropolitan Area Traffic Conditions Map [http://www.wsdot.wa.gov/regions/northwest/NWFLOW/bridges.htm#Anchor].
Icons follow the presentation of the traffic conditions map allowing the user to obtain information on a variety of different transportation modes. Figure 3 shows the icons used on the WSDOT-NW Internet site. Information on construction schedules, road closure schedules, emergency announcements, ferry boat schedules, real-time incident information, and transit services and schedules are provided when the user clicks on the icons. Figure 5 shows the icons used within the WSDOT-NW Internet site.
I-14 Figure 5. Transportation Information Icons on WSDOT-NW Internet Site [http://www.wsdot.wa.gov/regions/northwest/NWFLOW/bridges.htm#Anchor].
Measures of Effectiveness
The WSDOT-NW established an E-mail account entitled [email protected] to conduct a survey of the users of the site. Out of approximately one thousand E-mail messages received, all were generally positive with complaints voiced about the down time of the service. Another E-mail account was established to handle questions about the site ([email protected]). Because so many similar questions were received, a site was created of the frequently asked questions (FAQs). This has significantly reduced the inquiries to the trafficmaster.
I-15 Future Enhancements
WSDOT-NW plans to add text based real-time traffic reports, video snap shots from the closed circuit television cameras (CCTV) of actual traffic conditions, mountain pass road conditions, and automatic decoding of the rather cryptic incident pages to make them more user-friendly. The following excerpt of incident information illustrates the present difficulty in deciphering the incident information.
CURRENT INCIDENTS AND REPORTS (*=NEW/UPDATE) OPERATOR>>TTD **SP I-5 ML JN NE85TH ROLLOVER ACC 2 LL BLKD CCTV 0655 ---CL IS NOW OPEN, ONLY LL BLKD CCTV 0727 *EB SR18 JE ISSA/HOBART RD DAV BLK RL CAD 0728
The abbreviations are used to both decrease the amount of manual work of the operators in inputting the information and to reduce the size of the data packets that are sent to those who distribute the information to the public. Until the messages are automatically decoded for the public, a link is provided to a page that gives the meanings of the abbreviations.
Traveler Information Showcase of Atlanta, Georgia http://www.georgia-traveler.com
As the host of the 1996 Summer Olympic Games, Atlanta was chosen to showcase a variety of technologies for disseminating traveler information to the public. One of these technologies included the dissemination of traveler information via the Internet. During the writing of this report, the providers of information for Atlanta were extremely busy trying to prepare for the debut of these services. Therefore, a direct contact was never made with these providers as to the future enhancements planned for the Internet services.
Objectives
The objective of providing the transportation information on-line was to assist those living within and visiting Atlanta to get around during the Summer Olympic Games. It was hoped that the information services would inform those visiting the city of the transportation alternatives available within the city.
Information Services
Information services within the site include real-time traffic maps, transit route schedules, parking information, construction announcements, and locations of incidents (12). An on-line route- planning service is offered for those who wish to find the best vehicular route. It is not clear whether the route planning service is based on the shortest path or if it incorporates the shortest travel time, reflecting real-time traffic conditions. Links are provided to find out more information about transportation to the Olympic venues.
I-16 Measures of Effectiveness
The effectiveness of the information services developed for the Atlanta area are presently being evaluated. The transportation services during the Olympic games have been the subject of much scrutiny. A number of athletes claim that they missed their competitions due to complications within the transportation system. The showcase of information technology at the Olympics has presented a unique situation to test and refine the essence of traveler information systems. Much will be learned from this testbed application of a variety of ATISs.
Travlink of Minnesota http://www.hrb.com/travlink
"Project Travlink" is a component of Minnesota Guidestar, the Minnesota Department of Transportation's (Mn/DOT) approach to the development of intelligent transportation systems for the state. Buses within a test corridor of Minneapolis are equipped with CAD/AVL systems that use differential GPS technology which facilitates real-time adjustments in fleet operations, locating buses in emergencies, and fine-tuning bus schedules (13). To achieve a public transit environment that is reliable, efficient, and informative, this information is then made available to the public using a variety of display devices. Transportation information is disseminated through pagers, touch-screen kiosks, videotext terminals, and a site on the Internet (14). Mn/DOT recognized the potential to reach a large group of people both at home and at work by presenting the transportation information services on the Internet. The use of the Internet was not dependent on additional training since most users of Internet services are familiar with the general point and click routine of accessing information.
Objectives
Through a presence on the Internet, Mn/DOT hopes to provide commuters with information to enable them to make more informed choices on their mode of travel (whether it be drive-alone, carpool, or transit) (15). It is also hoped that the SOV commuter will recognize the reliability, scheduling, and ease of use of the transit system, thereby inducing a mode shift and increasing transit ridership.
Information Services
On-line information includes bus schedules, bus fares, locations of park-and-ride lots, bus service changes, added bus service for special events, and information on special facilities along the test corridor (downtown parking, guaranteed ride home program, rideshare, and express lanes) (16). Construction and maintenance activities are described. Services for the elderly and disabled are discussed. Real-time information is available through the CAD/AVL technology. Real-time bus status as well as real-time traffic incident and delay information are presented. An interactive transit trip planning service is provided which utilizes origin and destination information to recommend a transit route.
I-17 Measures of Effectiveness
The Travlink Internet site was initially developed only for demonstration purposes to showcase the type of information, ease of access, and possible marketing opportunities that the Travlink program could offer. During the model deployment initiative (Orion), this information will be marketed to the public. Customer feedback will then be solicited to determine the ease of use and recommendations for the display of the information on the Internet.
Future Enhancements
MnDOT is further developing a page within the Web site to provide real-time traffic information on corridors within Minneapolis and St. Paul. The site provides a graphical display of real-time traffic conditions based on travel speeds, highway improvements, and construction work zones. Figure 6 shows the freeway conditions as provided on the Web site at http://www.traffic.connects.com. The primary purpose of the Travlink site will be to provide transit information. An upcoming demonstration project for this effort will be referenced by the name Orion.
Summary
This section highlighted examples around the nation of agencies who are utilizing the Internet as a multimodal transportation information service. Much can be learned from their efforts to transmit this information to the public via the Internet. Likewise, the types of information provided within each of the Internet site case studies serve as examples to those transportation agencies wishing to develop comprehensive Internet sites. The quality of an area’s transportation facilities and services is important to those considering relocation of a home or a business. Communities who can offer transportation information and alternatives via an effective Internet Web site will have an advantage. Not only will the site help attract new citizens but it will also help efficiently manage the transportation network despite increased demand.
I-18 Figure 6. Real-Time Traffic Map of Freeway Conditions within Minneapolis and St. Paul, Minnesota [http://www.traffic.connects.com].
I-19 THE PERSPECTIVE OF THE PROVIDER
Those responsible for the Internet sites of Riderlink, Ventura County, Washington State Department of Transportation, and Travlink were surveyed to identify the perspective of the provider. The survey revealed common frustrations and concerns when conveying transportation information to the public via the Internet. Those agencies who are planning to develop an Internet site for transportation information will benefit from an early understanding of the difficulties and the lessons learned. The discussion is not meant to discourage the use of the Internet as an effective tool for disseminating transportation information to the public. In fact, all respondents were optimistic about the potential of the Internet to produce a more informed and smarter traveler.
Difficulties in Conveying Information
Despite the overall success of the programs, providers of transportation information services on the Internet have experienced several difficulties when trying to convey transportation information via the Internet. Extensive databases must be acquired, manipulated for compatibility, and constantly maintained in order to offer the public timely and accurate information. Administrative difficulties such as the lack of training and departmental direction may also hinder the development of an effective Internet site.
Maintaining the System
As the size of the area for which information is provided grows, so does the size of the database and the complexity of the entire system. Furthermore, Saturday and Sunday transit schedules generally vary from weekday schedules. Riderlink developed an automated process that directly builds the HTML (hyper-text mark up language required for transmission of data across the medium of the Internet) off of the central scheduling database. Further problems are encountered in the extensive manual effort required to reformat the information available from the database into appropriate, useful information for the customer.
Changes in bus schedules, which may occur periodically throughout the year, must be incorporated into the information available through the Internet. A recent service revision required six weeks of full-time work for one person to implement the necessary changes in Riderlink (5). Changes in static information, such as bus schedules, are easier to fix than changes to route maps or the introduction of new routes. However, transferring existing maps to electronic information can be troublesome and time consuming. This was the case for the VCTC while they prepared bike maps for Ventura County. The original maps were scanned in and then customized to be compatible and more user-friendly.
Travlink experiences similar problems in disseminating of transportation information, noting that it is difficult to maintain the respect of the users of the system when the system is not available during the quarterly changes to the transit schedules. The public is quickly disillusioned by such hindrances since the public has high expectations regarding the look and the transmission speed of information. Delays were also experienced in obtaining the new transit schedules in the correct format to be used by the ATIS system database. Budgetary restraints due to the operational test nature of the program required that conversion be done off-site.
I-20 Maintaining Financial Support for the System
Travlink project managers have noted the on-going challenge to provide proper support for a system that by nature does not fit neatly into any single agency structure (13). The effectiveness of providing transportation information on the Internet is difficult to quantify. Funding sponsors are eager to investigate the potential for information services to increase transit ridership, thereby reducing congestion from SOV commutes.
Transportation agencies are beginning to understand the value of allocating time and funding towards the development of a presence on the Internet. They are recognizing that the effectiveness of the site is dependent both on the reliability of the information and on the effectiveness of the presentation. Some agencies have acquired large budgets to demonstrate the use of the Internet as a tool for disseminating traveler information to the public.
Other transportation agencies contract out the initial development of Internet sites to private companies that specialize in the development of Internet sites. By utilizing the expertise of a design company, the Ventura County Transportation Commission was able to establish the framework for an effective presentation of transportation information at a relatively low cost. The VCTC contract also included training for the VCTC personnel on how to maintain and develop the Internet site.
Lack of Control Over Final Product
Managing the expectations of users is one of the most difficult steps in the design of an effective information system. In addition, browser software varies from user to user. Therefore, it is difficult to assure that the presentation designed by the provider will be identical to the display seen by the user. Updated browser software can be downloaded free from the Internet. However, each browser looks different and may be enhanced by user-selected options. Metro recognized that this could actually be considered a positive feature of the dissemination of traveler information via the Internet because the information can be supported on a variety of platforms (5).
Lessons Learned
The most common words of advice from those presenting information on the Internet is to "Keep it Simple!" A simple presentation of information is usually more valuable to the public than one that requires extra effort to find the information desired.
MnDOT of Travlink recommends to clearly state on the Internet site if information is available on a limited basis, as was their trip planning. Otherwise, there may be unreasonable expectations for the capability of the system. Inform the public of future enhancements planned for the Internet site and when these improvements can be expected.
MnDOT also advises the following: real-time information should be highly reliable and accurate; keep the time a system is off-line for updates to a minimum; make the system easy to understand and to use; and obtain as much feedback as possible during the design phases, so that the types of information and the presentation format match what the commuters want (13).
I-21 Overall Benefits
Despite the inherent difficulties in conveying information to the public via the Internet, the providing agencies do recognize overall benefits in providing the service. The information is made available to the public anytime during the day or night at a relatively low cost to the providing agency. The public can directly obtain the desired information with little to no assistance from the providing agency staff. The presentation of information via the Internet affords the providing agency staff an additional tool for reaching the public. Many agencies report that the Web site has increased the E-mail “traffic” from the public while reducing the phone calls to the offices. Agencies are recognizing that it is easier and more efficient to answer similar E-mail requests than it is to provide the same information over the telephone.
The transportation information on the Internet may attract those who do not typically use transit to get them to consider changing their present mode of travel. Answers to most common questions about how to utilize transit services can be fully described within the Internet site. This will allow a reluctant transit user to become more comfortable with the riding procedures, potentially increasing the ridership of the transit system and the satisfaction of the customer.
I-22 THE PERSPECTIVE OF THE USER
The needs of the user are critical to the design of an effective presentation of transportation information to the public. Today's society demands fast, convenient, and truly informative information. Failure to consider these components in the design of an ATIS on the Internet will hinder its effectiveness as a tool to alleviate congestion and driver frustration.
The perspective of the user was identified through three types of activities. First, a literature review was conducted to identify current research on the development of effective ATISs. This review also revealed information on user needs and constraints; characteristics of the commuter; and the propensity of the commuter to alter travel time, mode, or route.
A focus group study of potential users was then conducted to determine the accessibility of four of the Internet site case studies identified earlier (Riderlink, Go Ventura, Washington State Department of Transportation, and Travlink). Upon investigating these Internet sites, the user’s perspective concerning the display of transportation information was obtained. The section details the findings of the literature review, focus group study, and site investigations.
User/Traveler Needs and Constraints
The University of California at Davis is currently investigating the design of ATIS from the perspective of the user. Their ATIS Urban Travel Demand Simulation Lab allows the researchers to observe and closely analyze mode selection (drive alone, carpool/vanpool, transit) and route choice behavior (17). Researchers have identified that the effectiveness of pre-trip information systems is dependent on the ability of the system to provide the users with adequate, relevant, accurate, and timely information using effective display formats and appropriate interfaces (18).
In order to better identify the needs of travelers and the best means to present this information, the research team identified the following four objectives for the development of effective an ATIS:
1. Determine user needs and functional requirements for pre-trip information systems. 2. Determine user attitudes and preferences for alternative display formats. 3. Determine user preferences for different types of interfaces. 4. Develop guidelines for the design of pre-trip information systems.
Initial studies of the capabilities of possible interfaces (such as the computer monitor, speaker, telephone, and television) revealed that the computer monitor with a touch screen or a mouse based input interface is the most versatile combination allowing a wide range of data display formats such as text, tables, images, maps, diagrams, and speech (18). The Internet has, therefore, evolved into the perfect medium to incorporate these displays.
I-23 The Commuter
The Washington State Transportation Center identified four types of commuters based on their propensity to change various aspects of their commute in response to traveler information (19):
1. Pre-Trip Changers (16%) 2. Route & Time Changers (40%) 3. Route Changers (21%) 4. Non-Changers (23%)
The researchers further identified that the single most flexible driving decision is the departure time of the Pre-Trip Changer and Route & Time Changer groups; likewise, only the Pre- Trip Changer group showed a willingness to change transportation mode. The survey of drivers also indicated that most commuters prefer to receive traveler information prior to departure. Travel patterns and behavior will be different throughout the nation, given the unique demographics and land use of each city. These studies of commuter behavior within the Seattle area allow one to speculate that roughly half of these urban commuters are likely to utilize pre-trip planning tools provided on the Internet (assuming that they have access to the system).
In analyzing the trip behavior of participants for a Los Angeles study, over three quarters of the participants indicated that the primary purpose for their weekly travel was work related (20). Most commuters drive the same basic routes to get to and from work every day. Though many are extremely frustrated with the time and energy required to commute, few know how or where to find enough information to achieve a faster, cheaper, less stressful way to get to work.
A study to understand the effect of ATIS on commuters' route choice decisions found that those most likely to utilize such information services were those with a high level of education (e.g., college graduates), long-distance commuters, and/or people who reported uncertainty in travel time as a major problem (21).
Providing access to region-wide, multi-modal transportation information through a site on the Internet greatly assists the commuter. To make a smart choice about the best mode, time, and route for travel, the user/commuter benefits most when information on all options are available.
Male vs Female
Studies have shown that males and females react differently to transportation information. Interestingly, one study on the impact of traffic information on commuters' behavior found that more females (40%) listen to traffic reports before leaving home to go to work than males (33%), while more males (54.4%) listen to reports en route than females (47.7%) (21). As these findings suggest, it was also found that females more often change their routes or departure times as a result of listening to traffic reports before leaving their homes, while males more often change their routes as a result of traffic reports they hear while en route to work. These findings might indicate that females are more likely to utilize transportation information as provided on the Internet for pre-trip planning, given their propensity to gather information before entering their vehicles.
I-24 Comprehensive Nature
Both the traveler and the transportation system will benefit as a whole if multi-modal information is provided on a Web site for an area. This appeals to the traveler in that he/she can access all necessary information from one site rather than searching through a variety of key words on the Internet to assimilate the appropriate information to plan a trip. Only a small percentage of people would ever bother to take the time to search for such information.
The area's transportation system also benefits when the public is conveniently provided information. Public knowledge of the fastest route can potentially reduce fuel consumption and reduce congestion. Likewise, the public may be persuaded to take public transit if time and energy savings are easily recognizable. Furthermore, the interest of the public usually creates additional demand for information. The Travlink project developed as a demonstration project along a specific corridor. The public quickly recognized the value of the Travlink information service and began to demand that the trip planning assistance be provided for the entire metro area.
Focus Group Study of Accessibility
The perspectives of potential users of the case study Internet sites were also obtained through a focus group study. Students who were relatively familiar with search functions of the Internet served as volunteers. The students were presented with the following scenario:
You are a commuter within a certain city or area. A recent article in your newspaper mentioned that transportation information for your city or area is available on the Internet. While at work you decide to try to find this information by searching the Internet. You only remember a few key words from the article, and decide to use these as starting points for your search for transportation information.
Table 2 provides the key words which were presented to the volunteers as a starting point for finding transportation information on the Internet.
Table 2. Key Words Provided to Focus Group Participants.
Key Words Provided Hidden Objective Washington Department of Transportation Find Riderlink and Washington Seattle (King County) State Department of Riderlink Transportation Web Sites Minnesota Department of Transportation Find Information Provided by Minneapolis/St. Paul Travlink for Minneapolis and Travlink St. Paul California Department of Transportation Find Go Ventura Web Site Ventura County Transportation Commission Go Ventura
I-25 The most popular search engines used by the participants were Altavista (http://www.altavista.digital.com) and the Net Search options randomly presented on Netscape (Yahoo, Infoseek, Lycos, Magellan, Excite). The average time spent searching for transportation information for each site ranged from five to eight minutes. Many became frustrated when initial searches of the key words they “could remember from the newspaper article” did not yield the desired transportation information about the city or area.
When a link directed them to information about a particular mode that was provided by a different agency, many of the focus group participants could not easily understand how to return to the original agency’s Web site. For example, one participant chose to investigate ferry options, prices, and schedules by clicking on a ferry icon as presented in a list of transportation options for her community. The icon established a link to more detailed ferry information maintained on a different Web site by a different agency. After searching within this new site for desired information, she wished to return to the original list of transportation options for her community to investigate other modes of travel. The participant was somewhat familiar with the “Back” button feature provided by Netscape that allows one to retrace one’s steps along the information highway. However, the loss of understanding of the overall organization of the presentation of the information was unsettling and added to the frustration of the participant.
Additional comments from the participants are provided below:
C I would rather all information be presented within the visual field of one screen so that I do not have to scroll to find the rest of the information. C I skip over links that contain gopher text information unless I am really interested in the material. C I prefer graphical interfaces with clickable maps as opposed to text information. C I like icons of menu options repeated at the top of each page within the Internet site. C It is too hard to read black text on dark blue background. C I would prefer to know the address of the Internet site. C I would like to be able to more easily compare all of my transportation options.
Display of Information
The developers of an Internet site must consider the user’s perspective in order to effectively design the display of information. The public is very sensitive to the amount of time that is required to access information in advance of a trip. The average commuter is also extremely limited in the amount of time that can be allocated to pre-planning a trip based on transportation information. From an evaluation of each of the case study Internet sites, the following key considerations are provided as they relate to the effective display of information from the perspective of the user.
Attention Span
The attention span of the average "surfer" on the Internet can practically be measured in microseconds (22). While creative displays with colorful graphics are likely attention grabbers, the true value of a Web site is measured in the usefulness of the information provided. Most Internet users prefer simple approaches that clearly present the facts rather than incorporating fancy images which require longer time to download onto the screen (7). One comment on a Riderlink feedback
I-26 form stated that approximately one fourth of all Internet users even have the capability of displaying HTML graphics (5). Although an important consideration, this percentage will certainly change as the interest in and demand for access to the Internet grows and computer upgrades are purchased.
Use of Frames
Frames are one of the new features now available in Netscape Navigator 2.0. Frames allow designers to display the contents of several sites within the same visual field. Much like the panes of a window, each frame contains information from a unique uniform resource locator address. Ideally, frames were envisioned to allow the user to view the content of additional sites while maintaining a perspective of the overall context in which the information appears. For example, frames allow fixed elements, such as banners or navigation bars, to remain constant on-screen.
However, an initial encounter with frames can be quite frustrating. For example, for those who wish to view a previous frame, most resort to the browser “Back” button provided at the top of the screen. This feature does not call up the uniform resource locator (URL) address of the last fame viewed but recalls only the last URL address of an entire screen or frameset. User’s quickly find themselves farther “back” than they meant to be, without a clear understanding of how to resume their previous position. When navigating a site that contains frames, the user is best advised to use the navigation provided within the frameset. To return to a previous frame, the user must place the cursor inside the frame that originally displayed the desired information The user should then click the right mouse button to obtain a “Back in Frame” option from a pop-up menu.
More difficulties are encountered when the user decides to bookmark or print a page that contains frames. Adding a bookmark merely bookmarks the uniform resource locator for the original frameset, which may not be the bookmark that the user desired. Likewise, only the frame that is currently selected will print when the “Print” option is selected. The information can only be printed one frame at a time, rather than exactly as it appears on the screen.
Designers of sites with frames should keep in mind the frustrations of first-time users. The differences in navigating a site with frames should be explained to the user. Otherwise, the user might lose interest in navigating the site.
Speed of Transmission of Information
It is important to remember that most users accessing the Web outside of corporations, education, and government are dialing in at a slower rate through CompuServe, America Online, Prodigy, or through various Internet service providers (23). Therefore, the smaller the image the better for bandwidth and display reasons. Smaller images allow these users to display the image faster. A small image can serve as a preview of a larger image by linking the small image to a file containing the full image. This allows the user to decide quickly whether he or she is interested in more details.
I-27 Using fewer colors within the images will reduce the compressed size of the file also speeding up the transmission of the information. Smaller images with less colors are more likely to be displayed correctly on the receiving end (typically an 8-bit screen). A particularly nice effect can be achieved through line art. Line art was popular in the 1920s before color was available. Examples of the effective use of line art are illustrated in Figure 7.
Figure 7. Example of Line Art Used to Present a Simple yet Effective Image [http://www.mrshowbiz.com/showbiz].
Weather Information
Weather conditions are of interest to the public. If the site provides current weather forecasts (or links to such information), usage of the Web site may increase simply because of this service. While visiting the site to obtain weather information, the public's interest may be aroused to investigate commute options if the information is presented effectively. In general, the public appreciates access to weather information when planning commute trips. Forecasts of inclement weather may influence the decision to take public transit. The Washington State Department of Transportation notices that hits (requests for information) to their home page nearly double during the winter months when many of the Western Washington rivers were flooding (10).
Information Security and Safety
On-line ridematching applications require the user to submit personal information such as name, address, employer address, and usual working hours. Researchers at the University of California at Davis have developed user needs and functional requirements for a real-time ridesharing system (24). Of primary concern among focus group participants was the ability to
I-28 safeguard personal information within ridematching applications. This can be achieved by incorporating user and system operator passwords. Every effort should be made to emphasize the procedures for ensuring the security of information submitted on the application. Unless the public is assured of the security of the system, they are not likely to resort to this service as a tool for changing their commute.
Summary
The perspective of the user is an important factor in the development of an effective Internet site for displaying transportation information. Research on the needs of the commuter, a focus group study of the site accessibility, and information display considerations were discussed as they relate to effectively providing transportation information on the Internet. The hectic lifestyles of most commuters dictate the development of an effective Internet site. Access to relevant and reliable transportation information must be easily provided. Otherwise, the commuter will not resort to the Internet as a valuable resource for transportation information.
I-29 WAYS TO IMPROVE THE DISSEMINATION OF TRANSPORTATION INFORMATION TO THE PUBLIC VIA THE INTERNET
The Internet shows great potential for becoming an effective tool for disseminating traveler information. The following recommendations were developed to assist agencies in planning, designing, and evaluating the use of the Internet for this purpose.
Planning Stages
Establish an Advisory Committee
Several agencies are responsible for transportation within an area. In order to effectively present transportation information to the public, these agencies should work together as a team when developing Internet sites that detail traveler information for an area. This advisory committee could discuss ways to seamlessly provide transportation information to the public to avoid duplicating efforts and appearing unorganized to the public. This committee should include representatives from both public and private information providers as well as citizens from the community, computer programers, and city planners. Everyone will benefit from the “team” approach to managing congestion problems within a community. Marketing the product will be easier if all players participate in the development and support of the product. This team will also be valuable in identifying sources for funding demonstration projects within the community.
Conduct Surveys and Focus Groups
To be considered a valuable resource to the public, the needs of the public must be identified and addressed within the development of the Internet services. Surveys of potential users will help the advisory committee identify what type of information should be provided and how this information should be presented. The needs of the user will vary within each city due to the land use patterns and travel characteristics of the community. Research currently underway at the University of California at Davis ATIS lab will help identify user needs, functional requirements, attitudes, and display preferences for the effective design of ATISs. The findings and recommendations of this research should be reviewed by the committee to further identify user needs and preferences.
Develop a Logo or Slogan
Associate the Internet transportation information services with a unique logo or slogan. The public will begin to recognize and look for the logo, associating it with valuable transportation information services for the community. Register the logo or slogan with several search engines so that the public can easily obtain the information even if they do not know the uniform resource locator (URL) address for the site. Sponsor orientation sessions to familiarize the public with the Internet services. Ventura County cleverly developed bookmarks, as shown in Figure 8, to advertise the need to “bookmark” the resources available through their Internet site.
I-30 Figure 8. Front and Back Views of Bookmarks Promoting Ventura County Transportation Commission Services on the Internet.
Coordinate with the Local Transportation Management Center
Many large cites around the world are developing Transportation Management Centers to more efficiently manage the surface transportation system. Police, traffic engineers, emergency dispatchers, and transit officials share these centers. The transportation system benefits greatly from the improved communication between the various agencies who each have a role in servicing the transportation system. Much transportation data is collected at these centers and could be disseminated to the public via the Internet.
I-31 This combined effort from those agencies represented in the Transportation Management Center could facilitate a seamless display of transportation information for an area. The accuracy of multi-modal and multi-agency information could be better maintained because of the improved communication between the various providers of information. Software could be developed to automatically incorporate transit schedule changes in the information presented to the public via the Internet site.
Transportation Management Centers should also establish appropriate “firewalls” when relaying information to the public through an Internet site. The Internet introduces a two-way connection between the user and the provider of information. If the Transportation Management Center provides links to the Internet, the potential exists for deviants to achieve unauthorized access to internal networks and programs. “Firewalls” are being designed to secure systems against such intrusions.
Design Stages
Consider Human Factor Expectancy Issues
When developing the layout and the graphics within the Internet site, it is important to consider human factors expectancy issues. The following examples will illustrate this recommendation.
C Most people associate “North” with “up” when viewing a map. To match this expectation of the user, orient maps with North upward on the screen. When providing zoom options for a map, do not change the orientation of the map after the “zoom”.
C When illustrating how to fill in an interactive form that is provided on the site, use relevant examples that actually exist. When users are experimenting with the form, many will simply input the example origin and destination information; these people will become quite disillusioned with the service if their submitted request is returned due to an unknown origin and destination.
C To improve the readability of links to additional transportation information and services, present the agency’s icon or logo as the link. This adds credibility and familiarity allowing the user to readily identify the provider of the information. Figure 9 shows the links to additional transit services provided within the WSDOT Internet site.
Categorize Information
Many providers are displaying travel speeds with different colors on a map of the major freeways within the service area. Each color represents a five to ten mile per hour speed differential. Categories for slower speeds should be further defined. Drivers will appreciate the differentiation between “stopped” versus “stop and go” traffic. This distinction better reflects the conditions on the transportation network.
I-32 Figure 9. Examples of Using Agency Logos to Improve the Credibility and Familiarity of Links to Additional Information.
Utilize Landmarks
Utilize landmarks to highlight familiar or popular sights throughout the area. This will improve the readability of the maps. Landmarks are also helpful to tourists allowing them to determine the best route to or hotel near a particular site. As a service to visitors, hotel and landmark information could be accessed by providing a link to tourism information for the area. Develop a list of colloquial names used to refer to the various landmarks within the area. Include these names when developing a search engine database of keywords, streets, services, etc. to allow the public to quickly find the information desired.
Provide Reliable Links
When providing links to other sites that might be of use to the public, make sure the link address is current and the information is reliable. Otherwise, the user will be frustrated with the discrepancies and disillusioned as to the usefulness of other links and services. Obtain permission to link to a site, making sure to give proper credit where credit is due to the providers of the information. Include these other providers early in the planning stages of developing an effective Internet site for transportation information for the area. Encourage all providers to provide a clear link back to this main Internet site to minimize the frustration of the user when investigating various modes and agency information. Likewise, it is helpful to present icons of the various modes of transportation at the top of each page so that the user can more easily refer to additional information.
I-33 Incorporate Search and Reset Functions
Providing a search function that is not case-sensitive on pages throughout the site allows the user to quickly find desired information. Search features will become more valuable as the site becomes increasingly comprehensive, containing more detailed transportation information for the area. If the search engine was unable to locate the information requested, it is helpful to leave the original entry in the search box. The public can then make slight changes to the information rather than retyping all information. A reset or clear option could be provided to empty the present contents in the search box. The reset and clear options are also helpful when asking users to submit information for transit routing. The user can quickly alter a destination or origin without having to retype information that remains the same.
“Fit-The-Screen”
Attempts should be made to “fit-the-screen” when designing the presentation of the information. In eliminating the need to scroll down in order to view an entire map or image, the frustration of the user will be reduced.
Provide E-Mail Link
On each page, provide a link to send E-mail so that the user can easily make comments or ask questions while utilizing the service. Respond to E-mail comments promptly to assure the public that their opinions matter and will be considered in the development of the system. The user will greatly appreciate a timely response or answer to a question. Comments and suggestions should be documented appropriately so that changes can be made to facilitate the needs of the users. Develop a list of answers to frequently asked questions. Provide this information on the Internet to allow users to obtain the information they need without additional assistance from the providing agency staff.
Evaluation Stages
Monitor Use of the Information Service
The effectiveness of the services can be somewhat evaluated by monitoring the requests or hits to each page within the Internet site. A software program could be developed to graphically depict usage per month, per day, and per page, thus tracking the growth in requests or hits per month. By monitoring the usage of each page, the pages can be tailored accordingly to better match the needs of the user.
Survey Users of the System
Input from the users of the information services will provide valuable information to the developers of the Internet site. Those users who have commented through E-mail about the services will provide an excellent target audience for finding ways to improve the services. A survey could be provided on-line so that anyone interested may provide feedback. Riderlink used the following questions to help identify the audience and the useful features of the Internet services (5).
I-34 How did you hear about Riderlink (refer to the unique logo or slogan here)?
A. Reference on the Internet B. Newspaper or magazine article C. Word of mouth D. Metro (refer to logo of local transit agency) display or schedule rack E. Computer bulletin board F. Other
(Note: When providing the option of other within the answers, also provide a text input box so that the respondent can provide more detailed information.)
Approximately how often have you used Riderlink?
A. First time B. Two to five times C. Six to ten times D. More than ten times
How have you accessed Riderlink? (Indicate all that apply)
From work From home From a kiosk From school From a library
Why did you use Riderlink today?
A. For bus schedule B. For ferry schedule C. For traffic congestion D. For other Metro information E. Just browsing the Internet F. Other
How would you rate Riderlink’s ease of use?
A. Very easy to use B. Generally easy to use C. Neither easy nor difficult to use D. generally difficult to use E. Very difficult to use
I-35 How do you usually commute to work, school, etc.?
A. Drive alone B. By bus C. Carpool D. Vanpool E. Other F. Do not commute
If you drive alone to work, school, etc. has Riderlink influenced you to consider other commute option?
A. Yes B. No C. Do not commute
If you answered yes to the previous question, which options have you considered or tried? (indicate all that apply)
A. Bus B. Carpool C. Vanpool D. Bicycling E. Other
What other sources of bus service information do you use? (Indicate all that apply)
A. Bus schedule timetables B. Metro telephone assistance C. Bus-Time automated telephone system D. Do not ride the bus
What age group are you in?
A. 17 and under B. 18-24 C. 25-34 D. 35-44 E. 45-54 F. 55-64 G. 65 and over
What is your gender?
A. Male B. Female
I-36 What was the total gross income for your household last year?
A. Less than $7,500 B. $7,500 - $14,999 C. $15,000 - $24,999 D. $25,000 - $34,999 E. $35,000 - $54,999 F. $55,000 - $74,999 G. $75,000 and over
To better understand the physical commute patterns of the users, the zip codes of both the household and workplace could be requested. The public is more comfortable submitting this information as opposed to exact addresses. Provide an text input box where the user can provide additional comments and suggestions. Prepare an electronic mailing list of those who have sent E- mail after investigating the Internet site. Inform this audience that a survey is available on-line so that they can further recommend changes and comment on the system.
Continue to Refine and Improve the System
Use the E-mail comments and on-line survey results to continue to refine and improve the information services provided. Develop ways to offer customized transportation information to each user. AT&T offered a unique service through the Internet during the 1996 Atlanta Olympic Games. AT&T wanted to connect anyone interested to the people and the events that make the Olympic Games the most exciting sporting event in the world. Figure 10 shows the home page which introduces this AT&T communication service.
An on-line registration form was developed to personalize a user’s Olympic Games experience. This form allowed the user to register such information as hometown, country, gender, and zip code to allow the system to identify Olympic information that would be of most interest to the particular user. The user submitted both a real name and a user name for privacy within the system. Likewise, the user identified his or her top three favorite sports. This information was then processed and a password was selected by the user. Thereafter, upon accessing the “AT&T On-Line Switchboard” at http://www.olympic.att.com, the user could input a user name and password which then connected him or her to a personalized page. This page contained the latest information about the top three sports of most interest to the user as specified on the registration form. The user could make changes to the original registration form at any time to better reflect his or her interests. Likewise, search functions were provided to allow the user to search for additional topics and events of interest.
This approach towards the dissemination of relevant information to the public shows great potential as a way to disseminate transportation information. A commuter could input information about typical origin, destination, modes, travel departure time, and route. The system could then inform the user when a problem or incident occurred along an intended route. As the typical departure time approaches, the system could inform the user of the status of the bus that he or she usually rides home from work. Tailoring the information to the needs of the user benefits would likely increase the popularity of these information services and produce smarter travelers.
I-37 Figure 10. AT&T Olympic Games Connection on the Internet [http://www.olympic.att.com/cgi-bin/six/start.guml].
I-38 CONCLUSIONS
It has long been hypothesized that commuters who have quick and easy access to relevant, accurate, and timely information on existing traffic conditions, bus routes and schedules, and instant carpool matching services will be more likely to use public transportation and other high occupancy commute modes, perhaps also altering their time of travel and/or travel route (25). More informed travelers can exhibit smarter travel behavior which in turn can improve the efficiency of the transportation system as a whole.
In order for commuters to take advantage of such information services, the services should be integrated into the medium that most people access daily, namely the computer. Access to the Internet from both homes and offices is increasing exponentially. The Internet shows great potential for becoming an effective tool for the dissemination of transportation information. The Internet provides a mechanism to reach commuters who are not usually exposed to transit information. Likewise, the features of the Internet provide for seamless integration of multi-modal transportation information from multiple agencies. Customer feedback can be obtained immediately; this allows for continuous improvement of the information services to better address the needs of the public.
Despite the difficulties of maintaining the system, providing accurate and timely information, and developing an effective system design, providers of transportation information on the Internet do recognize overall benefits of this service. The information is made available to the public anytime during the day or night at a relatively low cost to the providing agency. The public can directly obtain the desired information with little to no assistance from the providing agency staff. Information on transportation within a city or area can be made available to people throughout the world within the comfort of their home or office, rather than being limited to certain target audiences and locations due to budgetary constraints.
Many transportation agencies are eager to provide transportation information to the public via the Internet. The preceding chapter outlined ways to improve the dissemination of transportation information through this medium. Consideration of these recommendations will facilitate the planning, design, and evaluation of an effective Internet site. Otherwise, the potential for the Internet to be considered as a reliable, efficient, and convenient source of transportation information may be jeopardized.
I-39 ACKNOWLEDGMENTS
This report was prepared for Advanced Surface Transportation Systems, a graduate level transportation engineering course at Texas A&M University. The author would like to express her sincere gratitude to Ginger Gherardi of the Ventura County Transportation Commission and to Les Jacobson of the Washington State Department of Transportation who served as mentors during the development of this paper. The author also wishes to thank Dr. Conrad Dudek for his direction and guidance towards the completion of this paper.
The following professionals volunteered their time to furnish information on Internet services sponsored by their respective agencies and/or additional support materials. Much thanks is extended to them for their assistance and quick response to the author's requests for information:
Daniel Fambro Associate Research Engineer, Texas Transportation Institute
Marilyn Remer Travlink Project Manager, Minnesota Department of Transportation
Steven DeGeorge Associate Transportation Planner, Ventura County Transportation Commission
Catherine Bradshaw Capitol Project Coordinator, King County Metro Transit (Seattle)
Bill B. Legg Assistant ITS Program Engineer, Washington State Department of Transportation
Michael Forbis, P.E. SC&DI Design Engineer, MS 120, Washington State Department of Transportation
Mark Morse TMS Software Engineer, Washington State Department of Transportation
Raghu Kowshik Post Graduate Research Engineer, Institute of Transportation Studies, University of California at Davis
I-40 REFERENCES
1. Casey, R.F., L.N. Labell, R. Holmstrom, J.A. LoVecchio, C.L. Schweiger, T. Sheehan. Advanced Public Transportation Systems: The State of the Art Update ‘96. U.S. Department of Transportation, Federal Transit Administration, January 1996, p. 85.
2. Sterling, Bruce. “Short History of the Internet.” [http://w3.aces.uiuc.edu/AIM/SCALE/nethistory.html]. From The Magazine of Fantasy and Science Fiction. February 1993.
3. Riderlink Home Page. [http://transit.metrokc.gov].
4. Bradshaw, C. “Seattle’s Riderlink Offers Commute Options on the Internet.” Congestion Management News. In ITE Journal. Vol. 65, No. 7, July 1995, p. 42.
5. Bradshaw, C., J. Wong, B. Morton, and R. Wade. Riderlink Demonstration Project: Evaluation Report. Report WA-RD 405.1. Federal Highway Administration, U.S. Department of Transportation, Federal Transit Administration, February 1996.
6. Bradshaw, C. Of King County Metro Transit. Response to survey as administered by Lee Anne Shull regarding the Riderlink Home Page. June 26, 1996.
7. DeGeorge, S. Of Ventura County Transportation Commission. Response to survey as administered by Lee Anne Shull regarding the Go Ventura Home Page. June 20, 1996.
8. Go Ventura Home Page. [http://www.goventura.org].
9. Maxwell Laboratories, Inc. Traffic Reports prepared for California Department of Transportation. [http://www.scubed.com/caltrans/transnet.html].
10. Forbis, M. and M. Morse. Of Washington State Department of Transportation. Response to survey as administered by Lee Anne Shull regarding the Washington State Department of Transportation-Northwest Region Internet Information Services. [http://www.wsdot.wa.gov], July 26, 1996.
11. Seattle Metro Traffic Flow Internet Site. [http://www.wsdot.wa.gov/regions/northwest/NWFLOW/bridges.htm#Anchor].
12. Atlanta Internet Site. [http://www.georgia-traveler.com].
13. Remer, M. Of Minnesota Department of Transportation. Response to survey as administered by Lee Anne Shull regarding the Travlink Home Page. July 1, 1996.
I-41 14. Wright, J., M. Remer, and F. Robinson. Minnesota Guidestar’s “Project Travlink”: Some Early Lessons. In Intelligent Transportation: Serving the User Through Deployment: Proceedings of the 1995 Annual Meeting of ITS America, March 1995, pp. 285-289.
15. Travlink Home Page. [http://www.hrb.com/travlink].
16. MnDOT Twin Cities Traffic Net Home Page. [http://www.traffic.connects.com].
17. Khattak, A., H. Al-Deek, Y. Yim, R. Hall. Bay Area ATIS Testbed Plan. Report UCB-ITS-PRR- 92-1. University of California at Berkeley, August 1992.
18. Srinivasan, R., R. Kowshik, K. Vaughn, K. Srinivasan, J. Gard, P. Jovanis, and R. Kitamura. Advanced Traveler Information Systems: Opportunities and Risks. In Transportation Congress: Proceedings of the 1995 Conference (Civil Engineers-Key to the World’s Infrastructure). October 1995, p. 369.
19. Hasselkorn, M., W. Barfield, J. Spyridakis, L. Conquest, D. Dailey, P. Crosby, B. Goble, M. Garner. Real-Time Motorist Information for Reducing Urban freeway Congestion: Commuter Behavior, Data Conversion and Display, and Transportation Policy (Final Report). Report WA- RD 240.2 / TNW 91-04, Washington State Department of Transportation. June 1992.
20. Le Colletter, E., Y. Yim, and R. Hall. Evaluation of the Transit Information System in Southern California. Report UCB-ITS-PRR-93-10. University of California at Berkeley, August 1993.
21. Abdel-Aty, M., R. Kitamura, and P. Jovanis. Understanding the Effect of ATIS on Commuters’ Route Choice Decisions. In Intelligent Transportation: Serving the User Through Deployment: Proceedings of the 1995 Annual Meeting of ITS America, March 1995, pp. 237-245.
22. Salwen, P. Sticking with the Web. ASCE: Civil Engineering, June 1996, pp. 37-41.
23. Fleishman, G. Weaving the Perfect Web. Adobe Magazine, September/October 1995, pp. 69-73.
24. Kowshik, R., J. Gard, J. Loo, P. Jovanis, and R. Kitamura. Development of User Needs and Functional Requirements for a Real-Time Ridesharing System. Report UCB-ITS-PWP-93-22. University of California at Berkeley, December 1993.
25. Houston Smart Commuter. Technical Assistance Brief #6, June 1994. [http://www.fta.dot.gov/library/technology/APTS/tech10/APTSTAB/06HOUST.HTM].
I-42 Lee Anne Shull received her B.S. in Civil Engineering from Texas A&M University in May of 1995. Lee Anne is currently pursuing her M.S. in Civil Engineering at Texas A&M University. Prior to graduate school, she worked for Walter P. Moore and Associates, Inc. in Houston, Texas as a summer intern in the traffic engineering section. Lee Anne is currently employed with the Texas Transportation Institute as a Graduate Research Assistant. Her university activities include: Institute of Transportation Engineers; Chi Epsilon where she served as President (1994-1995); American Society of Civil Engineers where she served as Store Manager (1994), and Civil Engineering Student Advisory Committee where she served as Secretary (1994-1995). Upon graduation she will join the Houston staff of Kimley-Horn & Associates, Inc. Her areas of interest include: transportation planning and operations, safety implications of geometric design, and human factors.
I-43 A COMPARISON OF REAL-TIME FREEWAY SPEED ESTIMATION USING LOOP DETECTORS AND AVI TECHNOLOGIES
by
Joe van Arendonk
Professional Mentors Walter M. Dunn, Jr., P.E. Dunn Engineering Associates
and
Jack L. Kay JHK & Associates
Prepared for CVEN 677 Advanced Surface Transportation Systems
Course Instructor Conrad L. Dudek, Ph.D., P.E.
Department of Civil Engineering Texas A&M University College Station, TX
August 1996 SUMMARY
Freeway traffic management is an integral part of a city’s transportation system. Once a freeway’s performance deteriorates , the whole system suffers and high levels of driver frustration, air pollution, and wasted time are incurred. To properly manage a freeway, methods of surveillance must be found which are cost-effective and efficient. The most common technology to measure freeway speeds has been the loop detector. One problem with detectors is that a single detector, using lane volume and loop occupancy to estimate freeway speeds, can produce invalid speed estimations because an average vehicle length is assumed for all vehicles. With two detectors acting together to form a “speed trap”, inaccurate results might result since loops are not good at detecting congestion between loop locations. In addition to these drawbacks, loops are very costly to maintain and require the closure of a lane of the freeway which impacts the flow and capacity of the roadway.
Since loops have their disadvantages, transportation engineers have been looking at Advanced Vehicle Identification (AVI) technologies to measure freeway performance. It is the intent of this report to compare both loop detector systems and AVI systems in terms of how they measure freeway speeds. This will hopefully provide transportation engineers with a guide to choosing an appropriate system. The results will then be applied to the city of San Antonio. The objectives of this report are to (1) determine an optimal spacing of AVI roadside readers (along and across the freeway) and probe vehicle density (number of vehicles with tags) to measure average freeway speed, (2) determine an optimal spacing of loop detectors to measure average freeway speed, (3) compare both costs ( installation and maintenance) and accuracy/effectiveness of AVI systems and loop detectors to measure freeway speeds, and (4) investigate how the results could be applied to the city of San Antonio.
The results of a review of literature and discussions with professionals in the field revealed that the optimal spacing of AVI readers is between 2 and 3 miles for congested roadways and between 3 and 4 miles for uncongested roadways. At least 0.8% of the vehicles in the traffic stream on an AVI monitored freeway must be tagged or probe vehicles in severely congested conditions. For loop detectors, the accepted practice has been spacing at a half mile.
It was found through the survey that the cost for installing an AVI system and loop detector system is approximately the same; however, the maintenance costs for an AVI system are more expensive. In terms of accuracy, both loop detector systems and AVI systems provide accurate results; however, single loop detectors can give less accurate results at slower speeds. In addition, loop detector systems require a closer spacing for similar levels of accuracy and detectors cannot calculate travel times as well as AVI systems in congested conditions.
The results of this comparison were then applied to San Antonio to gain some insights into a real-world application. The costs and feasibility of installing and maintaining each type of system to the state of Texas for the San Antonio system was addressed as well as the system’s overall effectiveness.
It was recommended to use an AVI system on a small test section for San Antonio because AVI can provide additional benefits other than just speed calculations. Although the maintenance
J-ii costs were higher, it was assumed that costs would decrease as the use of AVI systems became more widespread. AVI will be implemented using the spacings and probe densities listed above. The benefits will be realized as greater accuracy of speed and travel time calculations in congested conditions is gained through AVI. Since AVI can track individual vehicles, it can be used to produce real-time location data for advanced public transportation systems, to manage transit fleets, and to regulate the use of HOV lanes.
J-iii TABLE OF CONTENTS
INTRODUCTION ...... 1 Background ...... 1 Problem Statement ...... 1 Objective ...... 2 Scope ...... 2 Organization of Report ...... 2
LOOP DETECTOR TECHNOLOGIES AND SYSTEMS ...... 4 Loop Detector Technology ...... 4 Calculation of Speed ...... 4 Studies ...... 6 Washington State Transportation Center (TRAC), 1993 ...... 6 Texas Transportation Institute (TTI), 1994 ...... 6 Minnesota Department of Transportation, 1984 ...... 7 Examples of Existing Loop Detector Systems ...... 7 Chicago System ...... 7 Seattle System ...... 8
AVI TECHNOLOGIES AND SYSTEMS ...... 9 AVI Technologies ...... 9 Speed Calculations...... 10 Studies ...... 11 Washington State Transportation Center ...... 11 Seattle’s Puget Sound Region Study ...... 12 Texas Transportation Institute ...... 13 Examples of Existing AVI Systems ...... 14 Houston System ...... 14 TRANSMIT System...... 16
SUMMARY OF FINDINGS FROM LITERATURE REVIEW ...... 18 Differences ...... 18 Advantages and Disadvantages ...... 18 Spacing Requirements ...... 19 Probe Density ...... 19 Accuracy ...... 20
SUMMARY OF FINDINGS FROM SURVEY ...... 21 Technical Information on AVI systems ...... 21 Houston’s data processing system...... 21 Uses ...... 23 Loop Detector systems ...... 23 AVI systems ...... 23 Accuracy of AVI systems ...... 24
J-iv Spacing ...... 24 Probe Density ...... 24 Costs ...... 25 Loop Detector Systems ...... 25 AVI Systems...... 26 Additional survey participants ...... 27 Illinois DOT...... 27 Mark IV Industries, Canada ...... 28 IBI Group BIA, Toronto, Ontario, Canada ...... 28
CONCLUSION ...... 29
IMPLEMENTATION OF RESULTS ...... 31 Introduction ...... 31 Implementation ...... 31 Purpose ...... 32 Extent...... 32 Equipment and installation ...... 34 Tagged vehicle requirements and distribution ...... 35 Cost ...... 35
RECOMMENDATIONS ...... 36
ACKNOWLEDGMENTS ...... 37
REFERENCES ...... 38
J-v INTRODUCTION
Background
Freeway traffic management is an integral part of a city’s transportation system. Freeways are the highest speed roadway facilities that allow motorists to travel both short and long distances without stopping for traffic signals. The freeway system provides mobility to all parts of the city in generally the least amount of travel time. Once a freeway’s performance deteriorates , the transportation suffers and high levels of driver frustration, air pollution, and wasted time are incurred. To properly manage a freeway, methods of surveillance must be found which are cost- effective and efficient.
The most common surveillance method used so far has been the loop detector system. Traditionally, loop detectors have been used to calculate freeway speeds by using the freeway volume and loop occupancy (the percentage of time a vehicle occupies space over the detector) (1). Loop detectors are typically spaced at a one half mile intervals in order to provide a good sampling of freeway speeds. Although reliable speed calculation results are produced by loop detectors, speed calculations can be slightly inaccurate when single detectors are used. The calculation is based upon an average vehicle length of 21.5 feet which can vary considerably by vehicle type and time of day (2). Loops are also not proficient at identifying congestion. Finally, loop detectors require frequent maintenance to remain reliable.
Automatic vehicle identification (AVI) technology is an advanced emerging method used to measure freeway speeds which has been primarily used for electronic toll collection (ETC). The AVI system consists of an electronic tag or transponder located in the probe vehicle, a roadside reader unit, a roadside communications unit, and a central/control communications center. Roadside readers must be placed along the freeway at a certain spacing, between one and seven miles (as demonstrated in Houston (3)), in order to provide an accurate representation of the average speed on the freeway. Each lane of freeway must be monitored by overhead antennae, usually requiring one per lane for accuracy. In addition, a density of probe vehicles of approximately 1%, as used in Houston (3), is needed in the traffic flow to provide an accurate speed calculation.
Problem Statement
Loop detectors have been used for a long time as a means for estimating freeway speeds, for instance, Chicago, Los Angeles, Long Island(INFORM), and Seattle are using extensive loop detector systems (4). However, loop detector systems are prone to errors in speed estimation and detection of congestion (5). In addition, loop detectors need maintenance regularly which results in a lane closure that causes delays and capacity reduction. For this reason many emerging technologies, such as AVI, have been developed to attempt to improve upon the shortfalls of loop detector technology. Cities such as Houston have been incorporating AVI systems to estimate speed and travel time (3).
In order to make an informed decision on using an AVI system, a comparison needs to be made between an AVI and loop detector system. Important items to compare are roadside reader and
J-1 loop detector spacing, installation and maintenance costs, and accurateness of speed estimations. In order to gain a better understanding of the requirements needed to implement an AVI system or loop detector system it is useful to investigate the different uses of freeway speed measurements. It is also important to establish the density of probe vehicles needed for AVI systems to work properly since this density affects costs and accuracy. It is the intent of this report to investigate whether these criteria are currently available or are being developed.
The results of this comparison will then be applied to a city such as San Antonio to gain some insights into a real-world application. The costs and feasibility of installing and maintaining the chosen system for San Antonio will be addressed as well as the system’s overall usefulness.
Objective
The objectives of this paper were to:
1. Determine an optimal spacing of AVI roadside readers (along and across the freeway) and probe vehicle density to measure average freeway speeds used to generate the color coded Internet maps. 2. Determine an optimal spacing of loop detectors and AVI to measure average freeway speed. 3. Compare both costs ( installation and maintenance) and accuracy/effectiveness of AVI systems and loop detectors to measure freeway speeds. 4. Investigate how the results could be applied to the city of San Antonio.
Scope
The scope of the paper included investigating current transportation systems that use loop detectors systems and AVI technologies as well as examining emerging AVI technologies and emerging speed estimation techniques. The uses of speed data from both loop detectors and AVI were investigated to gain a better understanding of how the system should be constructed to meet the needs. The information presented in this paper was obtained from available literature and discussions and correspondence with various professionals.
Organization of Report
This paper is organized into three basic sections: a discussion of the findings from a literature review of AVI and loop detector systems, a discussion of the findings from a survey of transportation professionals, and the implementation of the findings to San Antonio.
Study Approach
In order to best study this subject area, an extensive literature review was performed to understand the state-of-the-art in AVI and loop detector technology as it pertains to measuring freeway speeds. Current transportation systems using both technologies was investigated through a literature review and through contacts with various professionals in the field. Recent and current studies related to using AVI and loop detectors for measuring freeways speeds was investigated through a questionnaire presented to transportation professionals. As a result, the reader will have
J-2 a better understanding of the advantages and disadvantages of each system as well as how to implement a system properly for measuring freeway speeds.
Once these tasks were performed the results were applied to the city of San Antonio which currently is using loop detectors to monitor a part of the freeway system. Guidelines were given for implementing the system as well as providing cost estimates. The benefits for the chosen system were explained as well as a comparison of the two systems as applied to San Antonio.
J-3 LOOP DETECTOR TECHNOLOGIES AND SYSTEMS
Loop Detector Technology
An inductance loop detector (ILD) uses an electrical wire that is placed in the pavement in the form of a loop. The inductance loop generally has about three turns of wire and is usually in the form of a square, about 6.5 feet (2 meters) on the side (7). It can also be in the form of a rectangle or a diamond. To power the loop, a detector unit sends an alternating electrical current through the wire loop. This current produces an electromagnetic field about the loop in and above the roadway. As a vehicle passes over the loop, energy is taken from the loop which changes the inductance and produces a change of frequency in the loop. If the change in inductance is greater than a pre-set threshold value, the passing vehicle is “detected.” ILD’s can be used to count vehicles and detect their speed. If used in conjunction with another closely spaced ILD, the two detectors form a “speed trap” and can more accurately measure speeds.
Inductance loop detectors operate in two different modes, presence or pulse. Presence mode, used with individual detectors, will identify the amount of time that a vehicle was on top of the loop while pulse mode which transmits a pulse, registers the arrival of a vehicle with the traffic control unit.
Calculation of Speed
Speed measurement data obtained through loop detectors are taken at a particular point on the freeway which is a type of measurement known as time mean speed. Information is not known about the speed of the vehicle between detector locations and the information tends to be incomplete. This becomes more evident at interchanges as the traffic is slowed down as a result of the entrance and exit ramps.
A single detector can estimate speeds based on the volume and occupancy counts. For instance, the Chicago Traffic Systems Center (TSC) uses the typical formulation for calculating speeds by assuming an average vehicle length of 21.5 feet (6). Speeds are determined using the following formula:
(1)
The value in the denominator, 40.9, is a conversion factor. From this estimated distance, travel time can be computed based on the estimated speed as follows:
(2)
J-4 To gain a perspective on the whole roadway, the travel times for each detector zone ( half the distance to each of the adjoining detectors) are added to represent a longer roadway segment.
When using a “speed trap”, the speed is calculated by dividing the distance between the two detectors by the time taken by the vehicle to travel between the two detectors. This time is measured from when the vehicle crosses the leading edge of each detector.
Since loop detectors only estimate speeds immediately upstream and downstream of the detector they are not very accurate for congestion detection. When spacing of detectors is greater than ½ mile, significant changes in speed can occur between the detectors without being noticed at the detector locations (5). This becomes more noticeable when the congestion occurs immediately upstream of a detector.
The situation is illustrated in Figure 1. The loop detectors at location A monitor near free- flow traffic speeds. The detector at location C will not detect congestion beginning to form at location B until the vehicle queue caused by the congestion reaches a point where vehicles crossing detector C start to slow in preparation for reaching the back of the queue that begins just upstream of A. The longer the distance from B to C, the greater the queue length must be before vehicle speeds over detector C are reduced by incidents occurring at Point B.
Figure 1. Congestion Detection for Loop Detectors (5).
In addition to being slow to detect reduced speeds the detectors cannot determine how the delay between points A and C relate to total travel time within the section. As a consequence, the detectors cannot identify the complete scope of the congestion. Many urban traffic control centers are looking for more accurate measures of sectional travel times for use in emerging traffic control strategies.
J-5 Studies
Washington State Transportation Center (TRAC), 1993
The single detector can give inaccurate results because it assumes a vehicle length of 21.5 feet which may not be true at a given reading. Studies by the Washington State Transportation Center (TRAC) have been conducted to lessen this inaccuracy by improving on a speed factor, g, which is a function of the road topology and occupancy (1). This factor is calculated using the vehicle length and time of occupancy and therefore has the same limitations as speed estimated using equation (1). To improve the estimate of speed from volume and occupancy, the speed factor, g, must be estimated for each loop station. The speed at each location can then be calculated as:
(3)
where: Si = Speed at the ith site, Oi = Occupance at the ith site, Vi = Volume at the ith site, gi = speed factor at the ith site.
This study concluded that the new speed estimates developed by TRAC using a newly developed cross correlation technique produced valid results only in the low (0-15%) range of occupancy values. They recommended that further study be done in the higher occupancy ranges and mentioned that a predictor technique such as a Kalman predictor which uses speed as one of the state variables may be the next logical step. This predictor would “use the occupancy/density conversion applicable to the modest occupancy range to estimate the observed speed but would use the filtered estimate of the speed in updating the state variables. This would provide a mechanism that produces a speed and occupancy-to density conversion that is time dependent and is driven by the recent history of traffic conditions.”(1)
Texas Transportation Institute (TTI), 1994
The “speed trap” can also give invalid results. The accuracy of speed estimations is dependent on the trap length, inductive loop wire type, and consistency in design and use. In a study performed by TTI in 1994 it was found that a 29.52 feet (9 meter) spacing between detectors or trap length produced the best results (7). This distance provided the best balance between the minimum distance to avoid crosstalk interference and the maximum distance to avoid lane switching between detectors. The same study showed that loops formed using single conductor cable were not as reliable as those formed from multi-conductor cable. Multi-conductor cable has an outer sheath which holds all conductors in uniform proximity, and thus maintains a more uniform electromagnetic field.
The study concluded that it is essential that all loops be identical, use multi-conductor cable and operate on the same frequency with identical sensitivity settings. Loops are sensitive to various environmental, climatic and traffic operating factors which require frequent calibration.
J-6 Minnesota Department of Transportation, 1984
A study was made by the Minnesota DOT in 1984 to evaluate the reason for loop failures in the snowbelt region and in Minnesota specifically (8). This study was performed in response to the fact that 14 percent of their signal maintenance time was spent on repairing faulty detectors. Various state agencies within the snowbelt region were asked to respond to a questionnaire which asked two basic questions: (1) why did the loops fail and (2), what specifications and installation procedures were used by each agency. Responses from the questionnaire showed that the majority of failures were due to:
C Broken wires; C Deteriorated wire insulation; C Pavement cracks through the loop; C Corroded or wet splices; C Amplifiers de-tuned; and C Improper sealing of loop wire in the pavement.
From the second part of the questionnaire it was found that the only consistent response was that most agencies used the same gauge of loop wire.
The study found that during installation, Minnesota contractors do not give enough attention to the small items, such as the procedure for laying and sealing the loop wires, addressing the loop corners when cutting the pavement slots, and the proper protection of the wire when passing through an expansion joint or pavement-shoulder joint. In addition, Minnesota DOT’s crews do not follow the same installation procedure required of the contractor when replacing a loop that has failed, nor do they maintain consistency in their loop repair activities.
Hughes Aircraft Company, 1993
Hughes Aircraft Company performed a study which compared various vehicle detection technologies. Among the devices compared were microwave radar, ultrasonic detectors, active infrared detectors, passive infrared detectors, video image processors, inductive loop detectors, and magnetometer detectors. It was found that the accuracy of the inductive loop with respect to vehicle count was 99.4% (9).
Examples of Existing Loop Detector Systems
Chicago System
Chicago’s TRC has an extensive system consisting of 2,208 induction loop detectors along 136 miles of roadway. Loop detectors are spaced at every half mile in the center lane of a three lane roadway or the left-center lane of a four lane roadway. At every three mile position loop detectors are located in every lane and are also located at every entrance and exit ramp.
The Illinois Department of Transportation (IDOT) has computerized reports which provide near-real-time congestion and travel time information as often as every minute around-the-clock.
J-7 The travel time information is displayed on an Internet map which was initiated in 1995 in partnership with the University of Illinois at Chicago. Full development of this Internet access will include information on all expressways and tollways in the three-state Gary-Chicago-Milwaukee Intelligent Transportation System (ITS) corridor initiative. As frequently as every 5 minutes, whenever any significant congestion is reported, estimated expressway travel times are also reported following the congestion limits report. The limits of congested areas are listed whenever two or more adjacent, or once removed, expressway mainline detector stations are congested, based on 5- minute average detector readings (28).
Seattle System
Most of the traffic performance data from Seattle’s urban freeway system are gathered with electro-magnetic inductance loop detectors (10). The majority of the freeways have only single loop detectors per location rather than “speed traps”. The loop detectors provide the Washington State Department of Transportation (WSDOT) with volume estimates and lane occupancy estimates. As mentioned earlier in equation (1), they assume an average vehicle length in order to calculate the average speed of the vehicles. This method gives reasonable results; however, it is susceptible to considerable error. The vehicle length is not a constant value and the loop sensitivities vary as a result of different roadway geometries and electronic operating conditions. Calibration of the loop electronics does not eliminate the problems. By placing a second loop and forming a speed trap, WSDOT has been able to obtain more accurate results. A second loop also verifies the volume and occupancy data collected by the first loop.
Limitations were pointed out in a study conducted in 1992 by the Washington State Transportation Center (TRAC). For one, loop detectors can only estimate traffic conditions in road sections immediately adjacent to the detectors due to the time mean speed method mentioned earlier in the “calculation of speed” section. One way to overcome this is by placing detectors at closer spacings(11); however, the cost for maintaining and installing additional loop detectors can be too costly for the benefits gained.
J-8 AVI TECHNOLOGIES AND SYSTEMS
AVI Technologies
AVI is a technology used to provide wireless communications between a vehicle and a transportation center with the ability to identify each vehicle uniquely. There are four basic types of AVI systems: optical, infrared, RF/microwave, and inductive loop (12). Optical AVI systems have roadside readers that focus beams of light on passing vehicles. Vehicles equipped with an AVI tag, usually in the form of a bar code label, reflect light back to the readers (13). The reader then reads and identifies the vehicle’s code. Because optical AVI systems require clear visibility and precise alignment between the bar code label and the reader, these systems have not been widely used.
Infrared AVI systems use scanners similar to those used in optical systems; however, vehicles are equipped with transmitters instead of bar code labels. Both optical and infrared are limited by their operating range (less than 10 feet) (2). Since infrared systems have the same communications restrictions as optical, these systems have also not been widely used either (12).
Inductive loop-based AVI systems are comprised of conventional traffic loop detectors embedded in the pavement of roadways, roadside receivers wired into specific inductive loops, and transmitters installed on the undersides of vehicles. The loops serve as antennae for the reception and transmission of signals. As a vehicle equipped with a transmitter enters the loop field, a voltage is induced in the loop by the transmitter, causing the coded information to be transmitted through the loop in the pavement back to the roadside reader (12). This system can be used with existing loop detectors and therefore may be advantageous in certain cases.
RF/microwave systems have been used extensively for automatic toll collection systems and are currently being used for traffic management purposes. In this system, an electronic tag or transponder is attached to each probe vehicle and encoded with identification information about that vehicle (14). Antennae are mounted along the freeway at various spacings in order to read information from the tag. The tag is aligned to correspond to system antenna alignment. As the tagged object approaches an antenna, the antenna broadcasts a radio frequency signal toward it. The tag modifies a portion of the signal and reflects it back to the antenna. The reflected signal carries the identification code for the object. The antenna transmits the returning signal to the RF module where it is preconditioned and amplified before being sent to the reader. The reader interprets the ID code based on user-defined criteria. It can also append useful information such as time and date to the code. The reader stores ID codes in an internal storage buffer and then transmits the ID codes to a host computer or other data logging device.
There are basically two types of tags used in RF/microwave systems: read-only, and read- write. The read-only tag simply transmits programmed data to the reader. Read-write tags allow the reader to identify the tag from the programmed data and also “write” information into the tag based on the tag’s individual identification. For example, as a reader identifies a particular tag, information such as the milepost number can be written in the tag. This allows other traffic control centers to monitor traffic as it moves across boundaries.
J-9 More advanced tags are available which combine the features of read-only and read-write. The tag features internal memory capable of retaining information (15). The tag uses wireless, backscatter technology that responds to information from a roadside reader by reflecting and modulating the reader’s RF signal. They automatically adjust to and operate on any reader frequency within a broad band. This memory is divided into frames - one is used for status and control functions, while the remaining can be used for general read/write memory. Because the tag provides programmable frames, its memory can be partitioned for easy expansion or allocated to a number of applications ranging from electronic toll collection to traffic management, airport parking and automated port of entry.
Speed Calculations
In order to calculate the speed of the vehicle, the travel time of the vehicle must first be established. The travel time information is obtained by subtracting the time a vehicle passes two reader locations A and B. This is expressed mathematically as shown in the following equation:
(4)
where: TTi = travel time of any vehicle I, TPbi = the time vehicle I passes point B, TPai = the time vehicle I passes point A.
Since travel times vary from vehicle to vehicle, the mean travel time values of the section are much more meaningful to highway facility operators (5). This can be represented as the mean of travel times for some given length of time, as shown in the following equation:
(5) where: N = the number of vehicles passing through the section during the time span y.
The travel time just calculated represents the time period that has just ended. The next vehicle entering the section may experience a different travel time because conditions may have changed during the time that the vehicle traversed the section. However, under continuous flow conditions, the travel times obtained in this manner will accurately represent the section’s actual driving conditions (5).
Computing the standard deviation of the measured travel times yields a measure of the variation in vehicle speeds within the traffic stream. Calculations of this measure of the distribution of speeds is important for determining when conditions have actually changed and when measured changes are simply a function of the sampling process. By maintaining both a rolling average of
J-10 vehicle travel times and a historical record of the previous 5-minute period (or any other time period), the system can determine both current conditions and when those conditions begin to deteriorate as a result of congestion (5).
Studies
Washington State Transportation Center, 1992
The Washington State Transportation Center (TRAC) has been studying the potential benefits of using an AVI system for monitoring the performance of traffic and detecting incidents (5). In 1992, in order to evaluate the use of AVI, three AVI readers were purchased and installed on Interstate 5, south of the Tacoma CBD. The stations, spaced at roughly 1-mile spacings, consisted of reader antennae placed in the two right most through lanes of traffic.
The findings from the Seattle study concluded that there were two basic methods for using the AVI data. The first method involved measuring the volume of probe vehicles passing a single point and measuring their associated headways. The second method involved calculating the travel time for individual probes by the tag and time-of-passage information. The first method detected incidents more quickly than the travel time technique when the incident occurred immediately downstream from an AVI reader or when the road was completely blocked.
For both monitoring techniques, AVI system response is controlled by four basic variables; the headway of tagged vehicles, the distance between AVI readers, the speed of the vehicles on the roadway, and the number of vehicles that must be monitored to detect a change in traffic conditions. These four variables interact to determine the detection times possible with the AVI travel time technique. For instance, the more tagged vehicles there are the larger the spacing can be for the readers. The fewer the number of tagged vehicles, the tighter the spacing needed between readers.
Incidents and likewise changes in traffic speed can only be detected once a vehicle has traveled the distance between two readers. Therefore, it is limited by the frequency of tagged vehicles and the spacing of readers. The study concluded that for a heavily instrumented, urban freeway (1 mile spacings, 60 mph speeds, and 2 second headways), detecting a 10 mile per hour change in vehicles speeds for 5 vehicles will take an average of 46 seconds. For a less traveled roadway (60 second headways or 60 vehicles per hour), the 1 mile spacing requires 336 seconds (5 ½ minutes) to detect that same change in speed.
Although the frequency of tagged vehicles was very low for the Seattle Study, a lot of useful information was gained. Most importantly, the study found that the data can be used to determine 0the frequency of the occurrence of congestion, as well as the approximate length and severity of those occurrences. Besides uses for speed and incident detection, the AVI data can be used for air quality control and for calibrating information for the four-step planning models used in urban areas.
The Seattle study found that the infrastructure costs for a fully implemented AVI based detection system are roughly equivalent to those for a conventional loop system covering a similar geographic area. This did not include the cost of providing tags for the probe vehicles. Tag costs were approximately $10 to $20 each when purchased in bulk and as much as $50 to $100 per tag if purchased in small numbers and for more complex tags.
J-11 The study concluded that an AVI based system provides several basic advantages over loop detector based systems. The advantages include the following:
C provision of section speed data, rather than point speed data; C faster congestion detection than possible with conventional loop systems if AVI tags were widely used. For example, an AVI system with 1 mile spacing of detectors and 60 mph freeway speeds will take 46 seconds to detect a 10 mph change in speeds if 5 vehicles are needed for detection. C greater flexibility in control algorithm design; C direct computation of travel time and delay information needed for a variety of operational and planning functions; and C improved system performance and accuracy.
In addition the TRAC study found that the ability of the travel time technique to monitor changes in vehicle speed (given a large number of tagged vehicles) at any given detector spacing was greater than that of conventional loop detector systems at the same detector distance. In addition, the rolling average speed that can be kept by the AVI system yielded an excellent measure of the true performance of the roadway over whatever distance exists between the AVI readers.
The study also found various drawbacks including the following:
C the system requires a significant infrastructure that must be retrofitted to the existing roadway system. For example, AVI antennae must be placed above each lane which requires the closure of lanes at times. A connection must be made from the antenna to the roadside reader and then communication lines must be installed from each reader to the central processing center; C the system will be expensive to develop, install, and maintain; C lack of standardization in the AVI field may result in some vehicles having to carry more than one vehicle tag to operate on all of the facilities that want to use AVI technologies; and C public resistance to instrumenting vehicles may be strong, particularly if vehicle owners must pay for the vehicle tags and/or do not receive "benefits" equal to or greater than the cost of those tags.
The study recommended that an AVI based system should only be implemented where a considerable amount of AVI tagged vehicles already existed. Although the study did not specify the exact amount, it could be speculated that enough AVI tagged vehicles be available to produce at least a 1% probe density as will be shown in the following sections. An ideal location would be an urban toll facility that was already using AVI tags as part of its revenue collection system.
Seattle’s Puget Sound Region Study
TRAC performed a study in 1994 to investigate the use of AVI in Seattle’s Puget Sound Region (12). They chose to install an AVI loop detector based system because loop detectors already existed in this region. TRAC purchased 50 transmitters and 10 receivers from Detector Systems, Inc. The receivers were connected to ten inductive loops located in HOV lanes along the north Seattle I-5 corridor. The distance between two adjacent receivers ranged from 1 to 4 kilometers (0.62 to 2.5 miles), with the average distance being 2.6 kilometers (1.61 miles). 49 transmitters were installed on the underside of Community Transit buses, while one transmitter was installed on a WSDOT vehicle.
J-12 The AVI data were first checked for three types of internal consistency and one external consistency. The measures of internal consistency were (1) whether a bus recorded by two receivers was also recorded by a third receiver stationed directly between the two receivers, (2) whether a receiver ever recorded an unidentifiable vehicle, and (3) whether the time each vehicle was reported was consistent with other times recorded for that vehicle’s trip.
To measure external consistency, an observer stood on a freeway overpass near one of the receivers. The observer tracked the times the buses passed and noted whether the buses were in the HOV lane. These data were then compared to the data recorded by the AVI receivers to see whether the observer recorded a bus passing in the appropriate lane, but the nearest receiver did not.
The study found that 17 percent of the buses went undetected in the internal consistency test and 19 percent went undetected in the external test. It was not clear whether the missed detections were due to the AVI system, the cabinet, the loop system, bus location, or a combination of these. TRAC suspected that the loop system was the prime contributor to the failures.
TRAC suggested that further testing and troubleshooting would be helpful to determine the viability of the AVI system. Key questions to be addressed are (1) the causes of the failure rate, (2) whether these rates can be reduced using loop-based or other AVI technology, (3) the infrastructure costs, and (4) whether other technologies could more effectively or cost efficiently produce the desired data.
TRAC concluded that there were potential applications for loop-based AVI technology in the Puget Sound region. They emphasized that AVI requires a significant infrastructure and is most cost effective for gathering data on large numbers of vehicles traveling over known, loop instrumented routes within a relatively limited geographical area. Potential applications for AVI systems in the Puget Sound-area include (1) performance monitoring of HOV lanes, (2) regulation of HOV lane use, (3) real-time location data for advanced public transportation systems, and (4) transit fleet management.
Texas Transportation Institute
The Texas Transportation Institute performed a study based on Houston AVI data in January 1996 in order to calculate the minimum number of probe vehicles needed for AVI to provide accurate results(16). The study found that for 5-minute periods, a 95% confidence level and a 10% relative error, the required sample sizes range from 1 probe vehicle every 5 minutes for free-flow conditions (HOV lane segment) to 4 probe vehicles every 5 minutes for severely congested conditions. The required sample sizes calculated for the Houston AVI system were directly related to the travel speed variation. The sample size can be calculated for any system as long as the speed variations are known. In addition, they were able to confirm that a greater number of probe vehicles are needed on congested freeways than on uncongested freeways.
The study recommended that in order to improve the accuracy and reliability of the travel time data being collected by the probe vehicles, additional AVI tag readers should be installed where segment lengths exceed 3 to 4 miles. Reader sites should be installed every 2 to 3 miles on congested segments and every 3 to 4 miles on uncongested segments. In addition, the study recommended that additional AVI tags be distributed to HOV lane users.
J-13 Examples of Existing AVI Systems
Houston System
Installation of the system
More than 50,000 vehicles have AVI transponders which are read as each vehicle passes a roadside reader. Approximately 50,000 tags were distributed for use with the automatic toll collection while an additional 6,000 were distributed afterwards for the freeway surveillance. The additional distribution had to target peak period and HOV drivers to get specific information.
The installation of the system was comprised of four phases (see Figure 2). Phase 1, completed in November of 1993, involved installing 34 AVI readers at 2 to 4 mile spacings on about 20-mile sections of IH 10 Katy, U.S. 290 Northwest and IH 45 North Freeways and their HOV lanes. TxDOT issued 1,000 transponders to volunteers who traveled these roadways during the commute periods. The Metro Transit Authority installed transponders on all the buses that use the HOV lanes. Data on location, time and vehicle identification is collected by roadside readers and transmitted by radio to nearby field cabinets equipped with modems and telephone lines.
Phase 2, completed in June of 1994, expanded the AVI system to four other radial freeways and their HOV lanes and to the IH 610 Loop Freeway. TxDOT provided an additional 3,200 transponders during this phase. In Phase 3, completed in September of 1994, the AVI system was installed on the radial freeways and their HOV lanes including the IH 610 Loop Freeway and Sam Houston Tollway. The final phase 4 is still to be completed and involves installing AVI readers at half-mile spacing to provide better information for incident detection.
J-14 Figure 2. Installation Phases for the Houston AVI System (3).
Uses of Information
Houston has installed a system to collect, analyze, and distribute real-time travel time and incident information (17). This system is known as the Real-Time Traffic Information System (RTTIS). The system operates in the north and northwest sections of Houston. A survey performed by TTI in 1994, measured how users perceived the information obtained from RTTIS and how they reacted to it (17). The study found that the users felt the information was accurate and believable. Although the survey participants liked having both incident and travel time information, they responded that the incident detection information was more useful. The participants said that the information provided by the system directly affected their travel behavior in the corridor by causing them to change routes or delaying their departure times.
J-15 TRANSMIT System
The TRANSCOM System for Managing Incidents and Traffic (TRANSMIT) was initiated to establish the feasibility of using Electronic Toll and Traffic Management (ETTM) equipment for traffic surveillance and incident detection applications (32). ETTM technology offers the potential for using vehicles equipped with toll tags to serve as vehicle probes within the traffic stream of the area for which surveillance is being established. The TRANSMIT project operates on an 18 mile stretch along sections of the New York State Thruway and the Garden State Parkway. The primary system function, from the perspective of the TRANSMIT project, is the processing of traffic flow data for detection of incidents and identification of unusual congestion conditions.
Among the guidelines that were set to begin constructing the project were: reader spacings were to be maintained at 1.5 miles to give a maximum incident detection time of five minutes, and the percentage of probe vehicles was set at 0.9% for two-lane highways and 2.1% for three/four-lane highways. Currently, one reader is used to cover all lanes in each direction (two or three lanes, depending on location) (18).
Two system architectures were considered for TRANSMIT: centralized and distributed. The centralized approach is the traditional architecture used in most freeway surveillance applications. All processing is performed by a central computer located at a central location. The centralized approach benefits from a simple design, minimum requirements for new software development, and the ability to use existing incident detection software. In a distributed architecture, the processing functions are shared by field and central computers. The software design for the distributed approach is more complex because additional field unit software and a more complex field-to-center interface are required.
Each architecture approach requires different amounts of data to be transferred. A study was performed to see which approach would require more data transmission. The study found that the length of the vehicle ID had a significant effect on the communications requirements. In addition, the distributed architecture had greater communications requirements than that of the centralized approach. Because of this requirement and the fact that the distributed architecture requires more software development, the centralized approach was recommended for use with TRANSMIT.
Spread spectrum radio was found to be the least costly communications medium among copper or fiber optic cable, trunk radio, microwave, satellite, and meteor burst. Trunk radio was not chosen because of the problem of peak hour congestion in the New York City area. Microwave was eliminated because of anticipated difficulties associated with licensing a microwave system.
To implement the system, twenty-three ETTM sites were proposed. Existing overhead sign structures were to be used if they conformed to the 1.5 mile spacing requirement. New structures were to be built if no existing structure was in place. Cabinets housing the auxiliary data processor (ADP), multiplexer, reader card, and RF module were located within 120 feet of the nearest reader antenna. In addition, the RF modules were used to control the antennas in emitting RF radiation and receiving signals reflected by the tags in the vehicles.
J-16 The ETTM roadside equipment was to be connected to a spread spectrum/telephone cable communications system. The telephone cable was incorporated into the system because spread spectrum technology requires a line of sight between radios which was not available in some sections. In addition, the high speed radios which were specified for this project were not available in the necessary quantities to meet the project implementation schedule.
ETTM antennas and reader cabinets would be leased because future expansion of the system might have required purchasing different equipment to be compatible with other expanding systems. The construction cost for the operational field test was bid at $1,463,277.
J-17 SUMMARY OF FINDINGS FROM LITERATURE REVIEW
Differences
The essential difference between using AVI as opposed to loop detectors to calculate freeway speeds is the notion of space mean speed verses time mean speed. AVI, which uses space mean speed, calculates the vehicle travel time between two reader locations on the freeway while loop detectors use time mean speed and calculate vehicle speeds at a particular point on the freeway. Studies by TRAC (5) have shown that the space mean speed technique is better for monitoring changes in vehicle speeds than a time mean speed method. In addition, the rolling average speed that can be kept by the AVI system yielded an excellent measure of the true performance of the roadway for all the given reader spacings.
Another difference between AVI and loop detector methodologies is that loop detector systems do not need probe vehicles to operate efficiently. Essentially every vehicle is a probe and has a potential to be detected. This difference was not found to give loop detector systems any distinct advantage over AVI systems.
Advantages and Disadvantages
According to TRAC (5), the advantages of using AVI to calculate freeway speeds are:
C greater flexibility in control algorithm design; C direct computation of travel time and delay information needed for a variety of operational and planning functions; and C improved system performance and accuracy.
Loop detector systems were not found to have any distinct advantages over AVI systems except that a loop based AVI system may be feasible in some cases where loop detectors already exist in large numbers. TRAC did not receive reliable results from an AVI loop based system implemented in Seattle’s Pugent Sound Region and attributed this mainly to loop detector failures. They concluded however that there were potential applications for loop-based AVI technology in the region.
Some disadvantages of AVI systems according to TRAC are :
C the system requires a significant infrastructure that must be retrofitted to the existing roadway system; C the system will be expensive to develop, install, and maintain; C lack of standardization in the AVI field may result in some vehicles having to carry more than one vehicle tag to operate on all of the facilities that want to use AVI technologies and; C public resistance to instrumenting vehicles may be strong, particularly if vehicle owners must pay for the vehicle tags and/or do not receive “benefits’ equal to or greater than the cost of those tags.
J-18 Loop detector systems require plenty of maintenance to operate properly. A study by the Minnesota DOT in 1984 (8) found the following reasons for failures in loop detectors:
C Broken wires; C Deteriorated wire insulation; C Pavement cracks through the loop; C Corroded or wet splices; C Amplifiers de-tuned; and C Improper sealing of loop wire in the pavement.
Spacing Requirements
The systems studied in this report employing loop detectors, Chicago and Seattle, had detector station spacings of approximately a half mile. In Chicago, this spacing was chosen because it served the primary functions such as ramp control. The 1992 TRAC study in Seattle (5) concluded that a half mile spacing gave a very accurate representation of freeway speeds; however, when installing a new system, these close spacings can be impractical due to the costs involved. When spacing between loops increases to more than a half mile spacing, significant congestion can occur between loops without being recognized by the system.
The two systems studied that use AVI systems were Houston and TRANSMIT. Houston uses spacings of approximately 2.85 miles whereby the smallest spacing is 0.9 miles and the largest is 6.7 miles apart. The general guidelines specified a spacing between 2 to 5 miles; however, the actual spacing was dependent on the availability of suitable mounting locations. A 1996 TTI study (16) has recommended that some spacings may give more accurate up-to-date travel time data if the reader spacings are maintained at 2 to 3 miles on congested segments and 3 to 4 miles on uncongested segments. This may require that some readers be added to the system.
TRANSMIT uses 1.5 mile spacings between readers to give a maximum incident detection time of five minutes. This system is used mainly for incident detection and therefore the readers are kept at a closer spacing than in Houston.
Probe Density
The Houston system has approximately 1 probe passing a reader every minute which translates to a density of 1 out of every 100 vehicles, assuming a freeway volume of 100 veh/min. In a study performed by TTI in 1996, the minimum required sample size for Houston was found to be 1 probe vehicle every 5 minutes (0.2%) for free-flow conditions (HOV lane segment) to 4 probe vehicles every 5 minutes (0.8%) for severely congested conditions. The required sample sizes calculated for the Houston AVI system were directly related to the travel speed variation. The sample size can be calculated for any system as long as the speed variations are known. In addition, they were able to confirm that a greater number of probe vehicles are needed on congested freeways than on uncongested freeways.
The TRANSMIT system guidelines stated that the percentage of probe vehicles should be set at 0.9% for two-lane highways and 2.1 % for three/four-lane highways. In general, the accuracy
J-19 of the data increases as more samples are obtained; therefore, traffic data is more accurate during periods of high-use (rush hour) then periods of low-use (off-peak).
According to a Seattle study performed in 1992, the costs for a fully implemented AVI based detection system without distribution of tags are roughly equivalent to those for a conventional loop system covering a similar geographical area.
Accuracy
A single loop detector can inaccurately calculate speed because it assumes an average vehicle length of 21.5 feet. By using a cross correlation technique developed by TRAC, the loop detectors provided valid results only in the low (0-15%) range of occupancy values. A speed trap can provide much more accurate results; however, the spacing of these traps stations must be less than a half-mile in order to be good at detecting congestion and the costs can be too high for such close spacings.
AVI systems give very accurate results since the vehicle ID is used in order to calculate travel times. The TRAC study in 1992 concluded that this system can provide an accurate indication of congestion at a larger spacing then that required for loop detector systems.
Table 1 summarizes the quality of data acquired from the literature review.
Table 1. Quality of Information Obtained from Literature Review.
Loop Detectors AVI Technologies Technical Information Enough information obtained Need more information on data processing Accuracy Enough information obtained Need more current data Uses Enough information obtained Need more current data Spacing ½ mile is accepted practice Need more current data Probe Density N/A Enough information obtained Costs Need current figures Need current figures
J-20 SUMMARY OF FINDINGS FROM SURVEY
Introduction
A questionnaire was distributed to various transportation professionals (see Appendix). The questionnaire asked the individual if his or her organization uses or has information on AVI systems or loop detector systems. If they did, then the professional was asked to expand on his knowledge of these systems. For instance, the individual was asked to provide information on an optimal spacing for the readers or detectors and an optimal vehicle probe density. The participant was also asked to give his general opinion on the advantages and disadvantages of either system.
The survey was sent to 13 professionals and phone surveys were conducted on three individuals (see Appendix for a listing). Of the 13 participants, only two did not respond. Among the remainder, two did not provide very useful information; therefore, a sample of 9 useful responses was obtained. Although the majority were from Texas, the remainder were from different parts of the country.
Technical Information on AVI systems
Houston’s data processing system
The data processing system for Houston’s AVI system has the following software components: a Tag Information Management System (TIMS), a Tag Collecting Storing and Forwarding System (TCSF), AVIcalc, AVIview, and a Traffic Conditions Display (TCD) (19). This is shown in Figure 3. The TIMS is the software used to operate the Auxiliary Data Processor (ADP) computer which recognizes each tag at each reader station, adds a time and date stamp to the tag record, and communicates the record to the central site. The ADP computers relay information to the AVI Host Computer which transfers data to the TxDOT computer system. Most of the tag reads are transmitted to the Host Computer within 20 seconds from when they are read in the field. This is the time it takes to dial, connect and transmit the tag read to the host. The AVI Host Computer uses the TCSF software for processing and storing each tag read record.
J-21 AVIview Tag Collecting Tag Info. Mgmt Storing and System (TIMS) Forwarding AVIcalc System (TCSF) Traffic Conditions Display (TCD)
Figure 3. Data Processing System for Houston.
Data is then sent from the AVI Host Computer to the AVIcalc program to produce vehicle travel time, identifying and discarding any "bad" or "invalid" data, and forwarding this information to the AVIview programs for display. "Bad" data is data which does not conform to the majority of the data collected. This is usually caused by a probe passing a checkpoint, or reader station, and then either stopping or taking a detour before passing the next checkpoint. To find this “bad” data, AVIcalc compares each travel time value with the previous values for the roadway segment. This algorithm has proved successful.
To produce the average vehicle travel times along a segment of freeway, AVIcalc takes a rolling average of the previous 30 second travel times. For example, if a probe travel time is received, the program will look at the travel times received in the previous 30 seconds and average all the values. The travel time is converted to speed by using the known distance between checkpoints and stored in an Oracle relational database. AVIcalc uses the database to retrieve data.
AVIview is used to provide a visual display of the AVIcalc output. The display is provided in tabular form showing travel times, speeds and a historical plot of data by roadway section. AVIview also produces a color-coded map of Houston's freeways, including HOV lanes, showing speeds in 10 mile per hour increments using six colors, ranging from red for low speeds to green for free flow speeds. Data on the map is updated every minute. The AVIview display is provided to Houston Transtar, a multi-agency transportation and emergency management center, and to users of the Internet which has approximately 10,000 users per month. One unique feature of this Internet map is a Route Builder Utility which lets the user define a route in order to find the travel times on segments within the route and for the total trip. This feature requires that the user use AVI reader locations for the beginning and ending of routes. In order for this system to be very efficient, the reader locations must be located at entrance and exit ramps.
J-22 Uses
Loop Detector systems
TxDOT in Fort Worth, Texas is using their loop detector data to provide volume counts and the level of service on their freeways (20). Speed is a secondary measure of effectiveness. TxDOT, Dallas is using their data primarily for disseminating speed data to local news broadcasters (21).
AVI systems
Houston’s Transtar
AVI travel time information and speed data is used by traffic management centers such as Houston’s Transtar for travel surveillance, management, and incident detection/response. Travel information is disseminated to the public through public kiosk-type displays in County, City and TxDOT offices in Houston, as well as lobbies in workplaces. Public transportation agencies such as Houston’s Transtar Smart Commuter broadcast real-time traffic, and static bus schedule information to commuters. Information is also used to encourage car-pooling, public transportation, and use of alternative routes (19).
Houston Transtar uses the travel time and speed data for traffic surveillance, management and incident detection/response. The TCD, a multi-purpose mapping system developed for the Houston Transtar Center by Lockheed Martin, allows traffic operators in Houston Transtar to view AVI travel time data as well as loop detector data on a color coded map. Houston Transtar is staffed by personnel from TxDOT, the Metropolitan Transit Authority of Houston (METRO), the City of Houston, Harris County and two commercial traffic reporting companies: Metro Traffic and Shadow Traffic(19).
The AVI travel time data is disseminated in various other ways. Kiosk-type public displays have been setup at County, City and TxDOT offices in Houston, as well as lobbies in workplaces. The Transtar Smart Commuter, Commuter Information Delivery System (CIDS) is a FHWA Sponsored Field Operational Test which will disseminate real-time traffic and static bus schedule information to 700 commuters in the I-45 North Freeway Corridor (19). The participants will receive the information through an interactive telephone system and a portable Personal Digital Assistant to view the information. Another way that Houston is disseminating the information is through the City of Houston’s Municipal Channel which will show the AVIview map at timed intervals during the peak travel hours.
The AVI information is used to encourage car-pooling, public transportation, and use of alternative routes. For example, in Houston, both HOV lanes and mainlanes are monitored. The differences between travel time on and off the HOV are shown on changeable message signs, which show the time savings for each of these facilities. The information can also be used to evaluate whether a given freeway’s capacity is effectively utilized, thereby necessitating further expansion or parallel routes. According to Amtech Corp., AVI technology is not used for traffic enforcement due to the privacy issues involved (24). Registration of these tags takes place at the entity that issued the tag, not at the Traffic Management Center.
J-23 TRANSMIT
TRANSMIT is using the AVI data for origin and destination studies as well as fleet management of transit vehicles. They plan to expand the system to 85 reader sites to get more information on incident detection and travel times. The operators have found that AVI can solve unlikely problems such as sun glare (22). In addition, AVI systems can provide operating agencies the ability to monitor the impact of their diversion messages. AVI systems technology can be expanded to include third generation transponders which can read and write information into a vehicle tag.
Accuracy of AVI systems
Amtech Corp. claims that AVI is extremely accurate for calculating speed. TTI Houston also finds that AVI is producing accurate traffic condition reports which can be very useful for planning purposes(23). According to Amtech Corp., the most significant factors affecting accuracy are: (1) time synchronization between reader sites; (2) missed reads; and (3) anomalous reads.
The time synchronization problem can be abetted by synchronizing time among all computers on the system on a regular basis. Missed reads are overcome by having a suitable population size of tagged vehicles or “probes”. Missing one or two tags out of 100 is considered acceptable, given the population of probes in the monitored area. Lowering the missed read percentage would require more equipment per lane and therefore increase costs. According to Amtech Corp., for the Houston system, the cost / performance ratio was deemed acceptable (24).
Spacing
Amtech Systems Corporation provided the AVI equipment for Houston. The average spacing between reader sites was 2.85 miles whereby the smallest spacing was 0.9 miles and the greatest was 6.7 miles apart (24). The general guidelines specified a spacing between 2 to 5 miles; however, the actual spacing was dependent on the availability of suitable mounting locations. Each reader can monitor up to 18 lanes of traffic; however, practical installations usually limit the reader to 8 or 9 lanes of traffic. This allows most locations to have one reader monitoring lanes in both directions.
Probe Density
In order to get accurate average speeds a minimum density of probe vehicles are needed. According to Amtech Corp., the minimum number of vehicles needed to pass a reader site is between 30 to 40 per hour. This translates to a sample every 1.5 to 2 minutes. TTI Houston expressed the need for a slightly higher density of 1 sample passing a reader every second which translates to a density of 1 out of every 100 vehicles, assuming a freeway volume of 100 veh/min (18). Accuracy increases as more samples are obtained; therefore, traffic data is more accurate during periods of high-use (rush hour) than periods of low-use (off-peak).
J-24 Costs
Loop Detector Systems
From interviews with various professionals, it was found that the cost for a loop detector including installation in the pavement is approximately $1000 - $1500 per loop(25)(26). In order to install a loop on the freeway a lane of traffic must be closed which costs approximately $1200 to $2000 per lane. The cost for The Texas Department of Transportation (TxDOT) to install one loop detector station on a 4-lane freeway ( i.e. 8 loops) is about $8,670. This does not include the cost of closing a lane which may cost an additional $2,000 per lane. A local control unit (LCU) will handle approximately 40 stations (27).
According to an interview with a TxDOT professional, the communication path for the loop detectors in the district of Dallas, Texas is as follows (27):
Loops ----> Detector Amplifier Cabinets on Pedestal Pole Assemblies ----> Transmit on 25 pair 22 AWG communication cable to the LCU in a HUB Cabinet ----> Transmit from the Hub on 6 pair 22 AWG communication cable to a T-1 Digital Multiplexer in the Hub where many different data sources are combined ----> A Data Transceiver then converts the T-1 signal from the T-1 Digital Multiplexer to a Fiber Optic transmission line ----> The signal is transmitted over the fiber to a data transceiver, a T-1 Digital Multiplexer, and then to the SCU, which can handle up to 40 loop stations, and then to the Manager Unit.
Table 2 shows the costs of the communications equipment.
Table 2. Loop Detector Communication Costs (27).
Communications Equipment Cost 25 pair 22 AWG comm. cable $1.50 per foot 6 pair 22 AWG comm. cable $1.00 per foot T-1 Digital Multiplexer $12,000.00 Data Transceiver $2,400.00 Fiber Optic Cable (Multimode) $3.50 per foot
Assuming 1000 feet of cable, two T-1 Digital Multiplexers, two data transceivers, the cost for a communications system handling 160 loops would be $34,000.
J-25 The cost to the New Jersey Turnpike Authority for a loop detector system at the field location with the controller unit is about $58,000 per location (25) . This includes the cost of a controller unit attached to approximately 14 loops and the closing of the lanes of traffic necessary for the installation. The overall loop detector system for the NJTA encompasses 70 miles using 1000 loops. Single loops are placed in the center lane at a half mile spacing.
The maintenance costs associated with the NJTA system is approximately $550,000 per year for a 70 mile system using 1000 loops. This cost only reflects the cost at the field locations and does not include the communication and computer systems beyond the field locations. This can amount to a considerable cost beyond that just mentioned.
Dallas, Texas has a loop detector system covering 26 miles using 1,100 loops. Currently 60% of their loops are in need of some repair. They are short on the necessary funds to maintain the system properly and expect the cost to be approximately $92,000 per year for two years. The cost for replacing a freeway loop in Dallas is $2,000 per loop. The majority of the failures are due to inclement weather and the quality of the initial installation. TxDOT Dallas also mentioned that inspection of the construction activity is poorly performed (20).
AVI Systems
Houston system
The total cost for installation in Phase 1 and Phase 2 for the Houston AVI system was $1,731,470, and $2,632,767 respectively (19). The average cost per reader installation for each phase was $31,481 and $27,159 respectively (the cost for the TRANSIT system was between $30,000 to $50,000 per station). At an average spacing of 2.85 miles per station, the average cost per mile is approximately $10,000 per mile. The maintenance costs associated with maintaining the AVI equipment at each field station is $256 per lane per site per month. Assuming the Houston system has 86 sites with 8-lanes, the total maintenance cost would be $2,113,000 per year. Amtech also mentioned that a typical RF Module consumes 1.6 Watts of power.
The cost to operate the telephone lines for Houston’s AVI system is approximately $65,000 per year for Phase 1 and 2. Each ADP in the field requires one telephone line and approximately two telephone lines are needed at the central site for every three ADP’s in the field. Each field line costs an average of $40 per month.
J-26 Survey Results
The following table summarizes the information obtained from the survey.
Table 3. Review of Survey Results.
Installation Maintenance Probe Density Accurateness Costs
Loop Detectors C $8670 per C $550,000/year/ C 60% with station (8 70 mile system problems loops) + C $2,000 per loop C Poor inspection $8,000 to cut C $92,000/year is problem loops for 2 yrs C Weather effects C $58,000 per results station (14 loops) C $34,000 for communication AVI Systems C $31,000 per C $256/month/sit C 1 sample every station e/lane 1.5 - 2 min C $30,000- C 1 sample every $50,000 per ($2,113,000/yr.) min. station C $60,000 for C 1 % operations
Additional survey participants The survey included other participants who provided useful information yet were not included in the summary listed above. A brief summary of their responses are given:
Illinois DOT
Expansions underway will boost the Chicago loop detector network to nearly 153 miles of roadway. Chicago uses a half-mile spacing to serve their primary functions such as ramp control and interchange spacing (28). In addition, they stated that loop detectors will not be functionally replaced by AVI technology. AVI would only be used where loops did not exist. IDOT stated that the accuracy of their loop detectors have decreased with decreasing speeds, due to the fact that single loops generate volume/occupancy ratios to evaluate speed and use the vehicle length to estimate travel times. The difference in vehicle length becomes more pronounced at slower speeds.
IDOT is conducting a test of an AVI traffic management system using the Tollway’s Electronic Toll Collection (ETC) system. This effort will develop and test software for obtaining travel time information with the potential for expansion to the entire Tollway system. Tests are expected to be completed in the summer of 1996, with integration with the Corridor Transportation
J-27 Information Center (C-TIC) completed by the fall of 1996. The Tollway plans to outfit its entire system, approximately 200 miles, with ETC technology by the spring of 1998. IDOT has stated that AVI speed estimates will not functionally replace loop estimates, only add to coverage where no loops exist (28).
Mark IV Industries, Canada
Mark IV Industries stated that their readers can monitor up to 8 antennae at a time. The approximate cost for their equipment is $5,000 to $10,000 per lane per location and approximately three times this amount for installation. They also mentioned that their equipment is compatible or able to communicate with Hughes equipment. They claimed that Amtech, AT/Comm, and MFS did not have the capability to communicate with each other (29).
IBI Group BIA, Toronto, Ontario, Canada
They stated that they had information on transponders, roadside readers, RF antennae, and Roadside Communication Units. They also had information on using AVI and loop detectors to calculate freeway speeds. According to IBI, the optimal spacing of roadside readers was still a subject for review (30).
J-28 CONCLUSION
As the findings showed, loop detectors can provide accurate measurements of speed, especially if a “speed trap” is used. If a single detector is used the speed is calculated using the volume on the freeway and percent time of occupancy of the loop detector. This calculation is based upon the average vehicle length and decreases in accuracy as the speeds on the freeway decrease because the differences in vehicle length become more pronounced. At a half mile spacing, loops can provide a very accurate representation of freeway speeds and travel times in less than congested conditions. As conditions become more congested the ability of the system to detect changing speeds to calculate travel times decreases.
Loop detectors are very accurate at counting vehicles (99.4% accurate (9)) however the accuracy is dependent on the working condition of the detectors. According to studies on loop failures and interviews with professionals, it appears that loop detectors are prone to failures and are very susceptible to the weather.
The accepted spacing for loop detectors is at a half mile spacing which usually coincides with the existing interchange spacing of the earlier installed systems. No research has been conducted to provide an optimal spacing of loop detectors for calculating freeway speeds or for incident detection; however, it seems probable that the spacing can be greater than a half mile for the purpose of estimating speeds without incident detection. At a half mile spacing, loop systems can be used for incident detection and for speed estimations. The system can also provide accurate volume counts and can identify vehicles for special lane use, such as truck lanes and HOV lanes, by counting the number of axles or length of the vehicle.
AVI systems can directly calculate travel times by knowing the time a particular vehicle passed a given location. It can provide very accurate freeway speed estimations at distances of up to 3 miles. Although this paper did not address the issue of incident detection, it has the capability of detecting incidents depending on the spacing between antennae, percentage of probe vehicles, and the response time needed. AVI does not have the capability to accurately estimate freeway volumes unless the percentage of probe vehicles is very high.
AVI systems are not susceptible to the same kinds of failures associated with loop detectors; however, they do require constant maintenance and calibration. If the funds are not available for this maintenance then an AVI system can have failures and provide inaccurate results. Therefore, it must be stressed that only a city with large funds for traffic management should consider AVI as an option.
The cost for implementing an AVI system, excluding the cost for tag distribution, is comparable to that of implementing a loop detector system. A big drawback to an AVI-based system is that it requires the use of probe vehicles equipped with transponders; however, only 0.8% of the vehicles are necessary during severely congested conditions. In order to equip vehicles with transponders, the driving public must be willing to disclose their identity by carrying a transponder with their unique vehicle ID. In addition, in some cases the public must be willing to purchase these transponders even though no immediate benefit is gained. The ideal location for an AVI system is one in which there already exists a large base of vehicles with AVI tags such as an urban toll facility which is using AVI tags as part of its revenue collection system.
J-29 The maintenance cost for an AVI system is more than that for a comparable loop detector system. The cost to maintain a system like Houston is almost 2 million dollars whereas a 70 mile loop detector system on the New Jersey Turnpike costs $550,000 dollars per year to maintain. However, the professionals interviewed who used loop detector systems expressed the need for more funds and for better inspection procedures during installation and repair. Those locations operating AVI systems were not lacking funds and therefore a comparison could not be made in terms of funding. It can be assumed that an AVI system without proper funds for maintenance can be quite troublesome.
Assuming that as more AVI systems are implemented the maintenance costs will decrease ( due to larger use and less specialization in the field), then an AVI system will be more beneficial to a city in the long run. AVI has the advantage of being able to track individual vehicles through the system and can be used for such uses as real-time location data for advanced public transportation systems, transit fleet management, and the regulation of HOV lanes. In addition, AVI systems can provide operating agencies the ability to monitor the impact of their diversion messages and perform origin and destination studies. AVI systems technology can be expanded to include third generation transponders which can read and write information into a vehicle tag.
J-30 IMPLEMENTATION OF RESULTS
Introduction
The findings from the literature review and survey will be used to implement a traffic management system for the city of San Antonio, Texas. The system will be used only as a means to collect speed and travel time data to produce an Internet Map similar to that used in Houston and other cities previously mentioned. Currently, as shown in Figure 4, San Antonio has 26 center-line miles of freeway covered by loop detectors. The loop detector system is planned to eventually cover 191 miles. An AVI system is also a possibility if the Federal government agrees to allow San Antonio to be a test site for a complete AVI system. In this system, all vehicles would have transponders located in the licence plates as a part of registering the vehicle.
Since officials in San Antonio have already decided to implement a loop detector system on the remainder of the system, it would not be practical to assume that they would choose to implement an AVI system instead. An expanded loop detector system may be beneficial to San Antonio since transportation professionals are already familiar with the current system and using only one type of system may be less complex and cost effective.
Many professionals interviewed expressed the benefits of having the benefits of both loop detector and AVI systems. Loop detectors can give better information on freeway volumes since the detectors are able to count every vehicle passing over it; however, AVI can give more accurate travel time information. In addition, AVI can be used for other purposes such as transit fleet management and origin and destination studies because it has the capability to track individual vehicle ID’s.
It is recommended to implement a small scale AVI system in San Antonio on a section of freeway not presently covered by loop detectors. By analyzing the data gained through AVI, officials in San Antonio can determine the benefits of using an AVI system. Although it has been shown in the survey findings that an AVI system can be more costly than a loop detector system, the long term benefits of AVI and its diverse uses may prove cost effective. In addition, as more systems become implemented the cost of maintenance may decrease. This system should be used to obtain speed and travel time, not incident detection. The system can also be used to obtain origin and destination data and manage transit fleets.
Implementation
In order to implement an AVI system properly, certain items must be individually addressed:
C The purpose of the system, C The extent of the system, C The equipment and installation process required, C The tagged vehicle requirements and distribution process, C The cost of the system.
J-31 Purpose
The purpose of the system is to test the benefits of using AVI to measure freeway speeds and provide for OD studies and fleet management. It should be tested on a small section of freeway to limit the costs and provide a feasible objective. The system should accurately measure speeds and travel times on the section as well as monitor specific vehicles for the other purposes just mentioned. If the system fulfills its objectives, the city of San Antonio will be able to make a sound judgment on whether to consider installing the system on other parts of the system and whether such a system could eventually replace the use of loop detectors.
A secondary purpose of the system is to provide information for an Internet map. Although the section may be too small to make a large impact on the users of the map, it may still prove useful to a specific targeted audience.
Extent
The section of freeway should provide the operators of the system with an adequate amount of information to make a proper assessment of the system. In order to do this the section should handle transit vehicles and general purpose traffic. The section should also provide a good sample of traffic with different origins and destinations. An ideal location would be one which contains freeway to freeway connections in order to capture OD data. In addition the section should contain a number of entrance and exit ramps to provide more OD data and transit fleet management data.
With these criteria in mind, an 8-mile section of US 281 was chosen which extends from Olmos Park just north of the existing loop detectors to one mile north of loop L1604. This section is shown in Figure 4. It includes two freeway to freeway connections and two interchanges exist on the section to provide additional information. The length of the sections is reasonable since it will not involve a great deal of reader stations and provides plenty of information in a short distance.
J-32 Figure 4. AVI Test Section for San Antonio. Note: “ST” represents AVI station. (Map courtesy of H.M. Gousha.)
J-33 Equipment and installation
Hardware
An RF/Microwave system will be used. Another possibility was a loop based AVI system but due to the high loop failure rates and the results of the TRAC study in the Puget Sound Region it was not chosen. The equipment will be similar to the equipment installed in Houston since Houston’s system has proved reliable and useful. Antennae should be installed on the existing overhead signs at 2 to 3 mile spacings on the general purpose lanes and at 3 to 4 mile spacings on the HOV lanes. One antennae must be installed per lane to get an accurate reading. This will require that lanes be closed during installation. Standard lane closure procedures must be followed as well as the provisions for safety nets underneath the workers. Preferably, the work should be performed in off-peak hours and at night.
Antennae stations should be located so that they are able to detect where a vehicle entered or exited US 281. This requires that the stations be located downstream and upstream of an interchange as shown in Figure 4. Additional antennae stations should also be located on the intersecting freeways to obtain OD data. Only one station is necessary on either side of US281 as shown in Figure 4. Both these stations can identify vehicles transferring between freeways.
Additional stations should be placed on sections which are prone to congestion. For example, staff at TTI in San Antonio mentioned that a section of US281 was under designed for the actual freeway speeds (see Figure 4). Stations should be spaced at 1 to 2 mile spacings within this section in order to detect a change in speeds and travel time more rapidly and to detect the onset of incidents.
Preferably overhead structures should be chosen which span across the whole freeway so that all lanes can be monitored. If such a structure does not exist then additional antennae locations may have to be used to provide the required spacings.
All antennae are connected using wire cable to an RF Module located on the side of the road. The RF Module must be located safely away from the roadway to prevent out of control vehicles from striking the module. The RF Module is connected using wire cable to a Reader located in a safe location as well. A Reader can monitor up to 18 lanes at a time so more than one RF Module can connect to a Reader. The RF Module is used to precondition and amplify the antennae signal before it is sent to the reader. The reader then interprets the ID code based on user-defined criteria and can also append useful information such as time and date to the code. The ID codes are stored in an internal storage buffer and then transmitted to a host computer or other data logging device.
Each reader is connected to the central computer using telephone lines. A modem will be used to convert the data into a phone signal. A local hookup for the reader can be obtained from the telephone company. If the reader is not near a telephone line, microwave communications between two modems can be used to transfer the data to the nearest telephone. Power for the unit can be obtained through electrical wires or cables connected to a local power source.
J-34 Software
This test AVI system should utilize a similar data processing system as Houston’s which was developed by Amtech. At each reader site, a computer is used to recognize each tag, add a time and date stamp to the tag record, and communicate the data to the central site. Software should be used which has the similar capabilities of the Tag Information Management System (TIMS) software developed by Amtech.
Software must also be used to process and store each tag record as it is received from the reader station computers. Tag information is stored within an AVI central computer on a local database. This storing software is also able to monitor connections to the field computers and issue status messages if communications are lost or error messages are received from the field computers.
Information from the central computer can be analyzed to produce travel times and speed using a calculation software. As tag records are received the calculation software searches through the database to find the same tag ID at an earlier time. The software can then produce the travel time using the time stamp between the two records. Invalid data, such as extensive times between two checkpoints due to a driver detour, can be found by comparing previous values with this errant data. Finally, all the data is stored on a database system for access by display programs and other uses.
To display the map on the Internet, another software must be used to translate the values produced by the calculation program and display it on the Internet. The map could use the format of other cities’ Internet maps. Different colors can signify different travel times and speed. Two lines can be used to show the conditions in each direction.
In addition to the map, information can be obtained on transit vehicles and on individual vehicles for OD data. For instance, a vehicle can be detected entering US 281 from freeway 410 and similarly a vehicle can be detected leaving US 281 onto freeway 410. This information may prove useful in more complete OD studies.
Tagged vehicle requirements and distribution
The tags must be purchased by the city and/or state to be distributed. The cost is between $20 and $38 a tag (31). To target the proper audience, the Department of Motor Vehicles (DMV) must be consulted to find the names of peak hour riders in this section. Once a large enough group is found to produce a minimum of 1% of the traffic stream, a campaign must begin to distribute the tags. In addition to individually owned vehicles, tags should be distributed to transit vehicles whereby the vehicle ID is connected to that particular transit vehicle. Knowing this information can help locate transit vehicles.
Cost
The cost for the addition of AVI will be approximately $31,000 per station for the chosen section. Assuming 10 stations are needed (one at each end and five within the section and two at each intersecting freeway) the total installation costs including the communication installation will be $310,000. This amount takes into account the additional stations needed for mounting where fully spanning overhead structures are not available.
J-35 The maintenance costs for this system assuming a cost of $256/lane/station/month will be $184,000 per year. The operations cost for the phone lines will be minimal since the Houston AVI system spends $60,000 per year on a much larger system. The power costs should be minimal since each RF Module only uses 1.6 Watts of energy (31).
Implementing the AVI system in San Antonio will be a challenge since the system is already well adjusted to loop detectors. Operators of the system will have to learn a new system and communications lines will have to be clearly drawn between the two systems. In the end, San Antonio will have a traffic monitoring system that is capable of integrating with systems of the future. Hopefully if the Federal project is accepted, the city may have more funds available to implement a more complete AVI system.
RECOMMENDATIONS
The application of AVI for San Antonio can be applied to any other city. It would be advisable to implement the system on a small section of freeway at first and then expand to other parts if the system proves beneficial. The purpose of the system must be clearly stated in order to establish all the other criteria. For instance, a system for detecting incidents would require closer antennae station spacings than what was used in this case.
An ideal city to apply an AVI system would be a city which already has a toll facility and has available future funds for maintenance. This would lessen the burden of distributing tags; however, a public campaign may still be needed to provide the public with information and benefits of the system and to ensure the privacy of each vehicle.
Further research needs to be done to understand how well AVI can estimate freeway volumes. Since AVI can only detect a percentage of the freeway traffic it must use an algorithm to estimate the actual volume based on the known percentage of tagged vehicles. Another item that needs further research is how well the system can detect speeds between antennae stations in severely congested conditions.
J-36 ACKNOWLEDGMENTS
The author would like to express his sincere appreciation to Walter M. Dunn, Principal of Dunn Engineering Associates, and Jack L. Kay, CEO of JHK & Associates, Inc., for their guidance and help with this project. Special thanks are also extended to Ginger Gherardi, Leslie N. Jacobson, Colin A. Rayman, and Thomas C. Werner for their support during the preliminary stages. Special thanks are extended to Dr. Conrad Dudek for providing us with the unique opportunity to perform this study and to Ms. Sandra Mantey for her time and effort. In addition, the author would like to thank the following individuals for the information they provided for the survey:
Paul Manual, Marketing Manager IVHS, Mark IV Industries Ltd. I.V.H.S. Division. Mark E. Hallenbeck, Director, Washington State Transportation Center. Brian Cronin, Traffic Engineering Associate, PB Farradyne Inc. Shawn Turner, Research Assistant, Texas Transportation Institute. Kevin Balke, Assistant Research Engineer, Texas Transportation Institute. Dan Hickman, Research Associate, Texas Transportation Institute. William McCasland, Research Engineer, Texas Transportation Institute. Russell Henk, Associate Research Scientist, Texas Transportation Institute. Scott Stewart, IBI Group, BIA. Robert G. Neely, Director of Sales, Western U.S., Amtech Systems Corp. Tom Batz, Manager of Technology Development, TRANSCOM. Joe McDermott, Illinois DOT, District 1, Bureau Chief of Traffic. Bernie Wagenblast, Operations Manager, TRANSCOM. Tammy Herring, Freeway Management, Dallas, TxDOT. Bill Manning, Fort Worth, TxDOT. Stephen Venglar, Assistant Research Scientist, Texas Transportation Institute. Wenston Chafin, New Jersey Turnpike Authority.
J-37 REFERENCES
1. D.J. Dailey, M.P. Haselkorn, and N.L. Nihan, Improved Estimates of Travel from Real Time Inductance Loop Sensors, Washington State Department of Transportation, Washington State Transportation Center, University of Washington, May 1993.
2. Hamm, R. “An Evaluation of Travel Time Estimation Methodologies”. Graduate Student Papers on Advanced Surface Transportation Systems. Southwest Region University Transportation Center, Texas Transportation Institute, Texas A&M University System, College Station, TX. August 1993.
3. Levine, S.Z. and W.R. McCasland. “Monitoring Freeway Traffic Conditions with Automatic Vehicle Identification Systems”. ITE Journal. March 1994.
4. Written Correspondence from Walter Dunn, Dunn Engineering Associates, July 24, 1996.
5. M.E. Hallenbeck, T. Boyle, J. Ring, Use of Automatic Vehicle Identification Techniques For Measuring Traffic Performance and Performing Incident Detection, Washington State Department of Transportation, Washington State Transportation Center, University of Washington, October 1992.
6. J.M. McDermott, “Freeway Surveillance and Control in the Chicago Area”, Transportation Engineering Journal, American Society of Civil Engineers, Vol. 106, No. TE3, May 1980.
7. D.L. Woods, B.P. Cronin, R.A. Hamm, Speed Measurement with Inductance Loop Speed Traps, Texas Department of Transportation, Texas Transportation Institute, Texas A&M University, Research Report 1392-8, August 1994.
8. J. Hale, Study of Traffic Loop Failures, Minnesota Department of Transportation, Office of Research and Development, July 1984.
9. Klein, L.A., M.S. MacCalden, Jr., M. Mills, “Detection Technology for IVHS”, Proceedings of the IVHS America 1993 Annual Meeting, Washington D.C., IVHS America.
10. Internet: Seattle Traffic Conditions (http://http://www.wsdot.wa.gov/regions/northwest/).
11. May, Adolf D., Monitoring Detector Information and Incident Control Strategies, Institute of Transportation Studies, University of California, Berkley, August 1985.
12. E. Butterfield, M. Haselkorn, K. Alalusi, Potential of Automatic Vehicle Identification in the Pugent Sound Area, Washington State Department of Transportation, Washington State Transportation Center, University of Washington, July 1994.
13. T.F. Boyle, The Use of Automatic Vehicle Identification for Traffic Monitoring, Master’s Degree Thesis, University of Washington, 1992.
J-38 14. RF Identification System, Amtech promotional material, 1990.
15. IT2000 Tags, Intellitag products promotional material, 1994.
16. Turner, S.M. and D.J. Holdener, “Probe Vehicle Sample Sizes for Real-Time Information: The Houston Experience”. The 75th Annual Meeting Transportation Research Board, Washington D.C., January 1996.
17. Balke, K.N., G.L. Ullman, W.R. McCasland, C.E. Mountain, and C.L. Dudek, Benefits of Real- Time Travel Information in Houston, Texas. Southwest Region University Transportation Center, Texas Transportation Institute, Texas A&M University System, College Station, TX. January 1995.
18. Written Correspondence from Bernie Wagenblast, Operations Manager, TRANSCOM, June 12, 1996.
19. Written Correspondence from Dan Hickman, Research Engineer, TTI Houston, July 10, 1996.
20. Phone Interview with Mr. Bill Manning, Fort Worth, Texas Department of Transportation, August 1, 1996.
21. Phone Interview with Ms. Tammy Herring, Freeway Management, District 10, Dallas, Texas Department of Transportation, July 23, 1996.
22. Marshall, K.R., and T. Batz, “TRANSMIT: TRANSCOM’s System for Managing Incidents and Traffic”. Proceedings of the IVHS America 1994 ITE Annual Meeting.
23. Telephone Interview with William McCasland, Research Engineer, Texas Transportation Institute in Houston, June 12, 1996.
24. Written Correspondence from R.G. Neely, Director of Sales, Western U.S., Amtech Systems Corporation, June 26, 1996.
25. Telephone interview with Wenston Chafin from the New Jersey Turnpike Authority, June 12, 1996.
26. Written Correspondence from Brian Cronin at PB Farradyne, June 12, 1996.
27. Written Correspondence from Tammy Herring at the Dallas office of the Texas Department of Transportation, July 23, 1996.
28. Written Correspondence from Joe McDermott, Illinois DOT, District 1, Bureau Chief of Traffic, June 28, 1996.
29. Phone Interview with Paul Manuel, Mark IV Industries, Ontario, Canada, July 5, 1996.
J-39 30. Written Correspondence from Scott Stewart, IBI Group, Toronto, Canada, July 9, 1996.
31. Phone Interview with Robert Neely, Director of Sales, Western U.S., Amtech Systems Corporation, August 3, 1996.
32. Phone Interview with Tom Batz, Manager of Technology Development, TRANSCOM, Jersey City, NJ, July 31, 1996.
J-40 APPENDIX
QUESTIONNAIRE
I am a graduate student at Texas A&M and a research assistant at the Texas Transportation Institute. I am taking a course during the summer taught by Dr. Conrad Dudek entitled “Advanced Surface Transportation Systems” in which we must write a paper on a subject of our choice under the guidance of Dr. Dudek and two mentors. The subject of my paper is “A Comparison of Real-Time Freeway Speed Estimation Using Loop Detectors and AVI Technologies.” I would like to compare the uses of the two systems for calculating average freeway speeds in terms of cost (initial and maintenance), accuracy of information, and use of information. At the end I hope to find an optimal spacing for placing roadside readers and loop detectors as well as a minimum probe vehicle density. My two mentors are Mr. Walter Dunn of Dunn Engineering and Mr. Jack Kay of JHK Associates. Please take time to answer the following questions:
1. Does your organization utilize or have information on Automatic Vehicle Identification (AVI ) technology?
Yes No
If yes continue. If no go to question #9.
2. What AVI technology does your organization utilize or have information on?
a. Transponder _____ b. Roadside Reader _____ c. RF antennae _____ d. Roadside Communication Unit _____ e. Other _____
3. Does your company utilize or have information on using AVI technologies to estimate average freeway speeds?
Yes No
If yes continue If no go to question 9.
J-41 4. What is the required spacing of roadside reader units along the freeway to give an accurate representation of average speeds and what would be the corresponding cost (both initial and maintenance related) per mile per lane? How many readers are needed per lane across the freeway? What is the justification given for the spacing, costs and amount of readers per lane given?
5. How accurate are AVI methods for calculating average freeway speeds? What are the inaccuracies and can you explain reasons for accuracy and inaccuracy? How does this accuracy compare with using loop detector systems?
6. What is the estimated density of probe vehicles (vehicles with AVI tags) in the traffic stream required to provide an acceptable accurate average speed measurement for all traffic? What is the justification for the fraction estimated?
7. For what uses are you applying the average freeway speed data obtained from AVI? How does this correlate to the reader spacing, probe density, cost and accuracy or the system?
8. How do the various components listed in question 2 interact or communicate with each other? Have you made a comparison of the different technologies available?
9. Does your organization utilize or have information on using loop detectors to calculate the average speeds on freeways?
Yes No
If yes continue. If no go to question #14.
10. Have you done any research into an optimal loop detector spacing along the lane (i.e., besides the standard half mile spacing) to calculate average freeway speeds? What is the justification for this optimal distance? How accurate are loop detectors in calculating freeway speeds? What are the inaccuracies and can you explain reasons for accuracy and inaccuracy?
11. What is the cost per mile per lane (both initial and maintenance) to operate a loop detector system? How can you justify this cost?
12. For what uses are you applying the freeway speed data obtained from loop detectors? How does this correlate to the loop spacing, cost (initial and maintenance), and accuracy of the system?
13. Have you made any comparisons in terms of costs (initial and maintenance) between AVI technologies and loop detector systems to measure average freeway speeds? What were the comparison results and your justification for the results?
J-42 14. Could you provide any documentation on current research or practice (i.e. reports, working papers, calculations) involving the use of AVI technology or loop detectors to predict average freeway speeds and to support your answers to the above questions (if applicable) ?
15. Could you provide a list of individuals, organizations, or companies that may be using AVI technology or loop detectors to predict freeway speeds?
Thank you for your time and cooperation.
Yours Sincerely,
Joe van Arendonk
Please return responses to:
Joe van Arendonk Texas Transportation Institute CE/TTI Bldg. Room 304D Texas A&M University College Station, TX 77843-3135
Fax # 409-845-1727 Phone # 409-845-9881 E-Mail: [email protected]
J-43 Joe van Arendonk received his B.S. in Civil Engineering from the State University of New York at Buffalo in 1993. Joe then worked as a structural engineer in New York City for two years. Joe is currently pursuing his master’s of science degree in Transportation Engineering at Texas A&M University. Joe has been employed by the Texas Transportation Institute as a graduate research assistant since September 1995. He has been involved in the ITE student chapter as Chapter Librarian and active member. His areas of interest include: traffic operations and computer visualization.
J-44