INSTITUTE OF TRANSPORTATION ENGINEERS
A TOOLBOX FOR ALLEVIATING
TRAFFIC CONGESTION AND
ENCHANCING MOBILITY
DOT/FHWA 150240 A TOOLBOX FOR ALLEVIATING
TRAFFIC CONGESTION AND
ENHANCING MOBILITY
Institute of Transportation Engineers
Prepared by Michael D. Meyer, Ph.D., P.E. Georgia Institute of Technology The Institute of Transportation Engineers published the first edition of&e Toolbox in 1989. Thii edition was one of the first efforts to develop a comprehensive summary of all the tools available to “solve” the urban con- gestion problem.We have learned much since 1989, and much has happened in the way of how we look at the urban transportation system and the types of strategies that can now be considered in a toolbox. Perhaps most dramatically, we are now seeing the initial application of advanced electronic technologies to better manage the transportation system. Known as intelligent transportation system (ITS) technologies, these tools are laying the foundation for the management of system operations that will be the basic component of many urban areas’ transportation strategy in the not-too-distant future.
In addition to ITS, there are several other tools discussed in this edition that are not found in the earlier ver- sion. These include: nonmotorized transportation, transit-oriented development and urban design, traffic calming, freight movement, congestion pricing, intermodal terminals, and multimodal corridor investment. The remaining sections from the 1989 edition have been greatly expanded and updated. In many cases, the original chapters have been kept largely intact with new material added.The authors of the original chapters were: Chapter 1, Dr. Michael Meyer; Chapter 2, Thomas E Humphrey; Chapter 3, Dr. Michael Walton; Chapter 4, Katherine Hooper and Robert Stanley; Chapter 5 and 6, C. Kenneth Orski; and Chapter 7, Peter A. Peyser Jr. This edition was prepared solely by Dr. Michael Meyer.
A final acknowledgement must be given to Stephen C. Lockwood, whose ideas expressed in a 1988 presenta- tion at the Annual Meeting of the Transportation Research Board entitled, “Kaleidoscope or Map: Suburban Congestion and Institutional Barriers” served as the basis of the “toolbox” analogy developed in this docu- ment.
Notice This document is disseminated under the sponsorship of the Department of Transportation in the interest of infor- mation exchange The United States Government assumes no liability for its contents or use thereof.
The contents of this document reflect the views of the Institute of Transportation Engineers (ITE) and the Federal Highway Administration (FHWA), which are responsible for the facts and accuracy of the information.The con- tents do not necessarily reflect the official views or policy of the Department of Transportation.This document does not constitute a standard, specification, or regulation
FHWA-SA-98436
Library of Congress Cataloging-in-Publication Data A toolbox for alleviating traffic congestion and enhancing mobility. p. cm. Includes bibliographical references. ISBN o-935403-12-4 1. Traffic congestion. 2. Traffic flow. 3. Traffic engineering. I. Institute of Transportation Engineers. HE336.C64T662 1996 388.3'14--dc21 98-4639 CIP Printed in the United States of America
US, Deaprtment of Transportation ite Federal Highway Administration Institute of Transportation Engineers 525 School St., S.W., Washington, D.C. 20024-2797 USA Telephone: +1 (202) 554-8050, Fax: +1 (202) 863-5486 ITE on the Web: http://www.ite.org
c 1997 Institute of Transportation Engineers. All rights reserved. Publication No. IR-054B 1.7M/BP/298
TABLE OF CONTENTS
Preface......
CHAPTER ONE - Traffic Congestion: An Overview...... 1 Why Worry? ...... 2 Transportation Today and Tomorrow...... 4 Mobility and Accessibility: The Bigger Picture...... 8 Can Anything Be Done?...... 9 Mobility and Congestion as an Areawide Multimodal Phenomenon: Development of a Coordinated Program...... 10 A Mobility/Congestion Reduction Toolbox...... 15 Intelligent Transportation Systems...... 16 Benefits and Costs...... 17 Commitment, Process and Public Involvement...... 19
CHAPTER TWO - Highways: Getting the Most Out of the Existing System ...... 23 Urban Freeways...... 23
l Freeway Incident Detection and Management Systems...... 23
l Ramp Metering...... 33
l Highway Information Systems...... 36
l Freeway Corridor Traffic Management (Including Arterial Surveillance and Control)...... 39
l Providing Additional Lanes without Wrdening the Freeway...... 43
l High Occupancy Vehicle (HOV) Facilities...... 46
l Park-and-Ride Facilities...... 55
l Highway Pricing Strategies...... 58 Arterials and Local Streets: Design...... 58
l Super Street Arterials...... 58
l Intersection Improvements...... 60
l One-Way Streets...... 61
l Reversible Traffic Lanes...... 63
l Arterial Access Management...... 65
l Traffic Calming and Street Space Management...... 70 Arterials and Local Streets: Operations...... 74
. Traffic Signal Improvements...... 74
l Computerized/interconnected Signal Systems...... 76
l Arterial Surveillance and Management...... 80
l Turn Prohibitions...... 82
l Improved Traffic Control Devices...... 85 Artenals and Local Streets System Management...... 87
l High Occupancy Vehicle (HOV) Facilities on Arterials ...... 87
l Parking Management ...... 92
l Freight Movement Management ...... 99
l Bicycle and Pedestrian Networks ...... 104 Enforcement ...... 109
CHAPTER THREE - Building New Road Capacity...... 115
l Multimodal Transportation Corridor Investment...... 117
l New Highways...... 121
l Access Control and Management...... 124
l Geometnc Design...... 125
l Reconstruction and Traff it Management...... 127
l Grade Separation...... 130
CHAPTER FOUR Providing Public Transportation Services...... 133 System/Service Expansion ...... 136 .Rail/Fixed Guideway Transit Facilitiess ...... 136 System/Service Operational Improvements...... 148
l Fixed Route and Express Bus Services (New and Operational Changes)..... 148
l Paratransit Services (Indluding Contract and Shuttle)...... 154 Supporting Actions/Policies...... 157
l Fare Structures...... 157
l Multimodal Access to Transit Services/Facilitiess ...... 162
. Multimodal/Intermodal Transit Stops and Terminals...... 165
l Transit-Oriented Development/Livable Communities...... 171
l Joint Development...... 180
l Transit-Oriented Parking Policies...... 184
. Transit Technology Applications...... 184
CHAPTER FIVE - Managing Transportation Demand...... 187 Important Considerations...... 187 Site-Specific TDM Strategies ...... 189 Alternative Modes of Transportation ...... 190
. Ridesharing ...... 190
l Nonmotonzed Transportation (Bicycling/Walking) ...... 197 Alternative Hours of Travel...... 203 Alternative Locations...... 205
l Telecommunications ...... 205
l Complementary Support Measures...... 213 Areawide Strategies...... 219
l Growth Management...... 219 .Urban Design...... 224 . Congestion Pricing...... 229
l Auto Restricted Zones...... 238 l Parking Management ...... 241
l Trip Reduction Ordinances ...... 247
l Negotiated Demand Management Agreements ...... 251
l Regional Multimodal Traveler Information Systems...... 254
l Transportation Management Associations...... 254
CHAPTER SIX - integrating Intelligent Transportation Systems Into Regional Transportation...... 257 Toward a Focus on System Operations and Management...... 257 Intelligent Transportation Systems Defined...... 258
l Regional Multimodal Traveler Information Systems (RMTIS)...... 263
l Traffic Signal Control Systems (TSCS) ...... 268
l Freeway Management Systems (FMS)...... 270
l Transit Management Systems (TMS) ...... 277
l incident Management Systems (IMS) ...... 281
l Electronic Toll Collection (ETC) Systems...... 282
l Electronic Fare Payment System (EFPS) ...... 286
l Railroad Grade Crossing Warning System ...... 289
l Emergency Management (EM) Systems ...... 290
Implementation of a Regional ITS Program...... 292 The Linkage Between ITS and Transportation Planning...... 293 Institutional Challenges in Implementing ITS ...... 298
CHAPTER SEVEN - Implementation, Funding and Institutional Measures . . . . .305 Traditional Funding Sources...... 305
l Fuel Taxes...... 306
l General Revenues...... 309 . Bonding ...... 310
l Other Revenue Sources (Targeted Taxes and Transit Revenues) ...... 311
Innovative Funding Sources...... 313
l Vehicle Use-Based Taxes...... 313
l Public/Private Partnerships ...... 316
l Development Fees, Exactions and Value-Added Taxation ...... 323
l Toll Roads ...... 327
l Privatization...... 330
Putting It All Together...... 332 Institutional Issues ...... 333
l Organizational Capability: Government Agencies ...... 333
l Transportation Management Associations...... 337
l Human Resource Development ...... 341
l Public Involvement and Marketing ...... 343 Putting It All Together in a Regional Program...... 348 IN THIS CHAPTER . . .
Why Worry?
Transportation Today and Tomorrow
Mobility and Accessibility: The Bigger Picture
Can Anything Be Done?
Mobility and Congestion as an Areawide Multimodal Phenomenon: Development of a Coordinated Program
A Mobility/Congestion Reduction Toolbox
Intelligent Transportation Systems
Benefits and Costs
Commitment, Process and Public Involvement
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY TRAFFIC CONGESTION: AN OVERVIEW
Over 40 years ago, the United States embarked upon the largest public works project in its history--the construction of the Interstate highway system. . . . . , ......
The urban portions of this system with changes to land development along with the highways and public procedures. Some actions provide transportation services developed by added capacity to highway and transit state, county, and local governments, systems so that passenger demand can as well as public transportation ser- be accommodated, while others vices offered by other organizations, attempt to change the characteristics have provided urban Americans with of the demand itself (e.g., by encour- unprecedented levels of mobility. aging ridesharing). However, no mat- However, in many communities ter what type of action is considered, increasing levels of traffic congestion those who are dealing with trans- have turned once easy trips into portation problems need to have nightmares. In addition, the lack of information on the likely effective-
accurate and timely public transporta- ness of different actions that can be The purpose of this Toolbox is tion information and services has used to deal with these problems. discouraged drivers from considering This Toolbox is designed to provide to provide local elected officials, options other than driving alone. this type of information. business leaders, and community People are turning to community The remainder of this chapter leaders with information on the officials for solutions. discusses the characteristics of trans- congestion phenomenon and The purpose of A Toolbox for portation in urban areas, its history, Alleviating Traffic Congestion and future trends, and the impacts and on the multimodal transportation
Enhancing Mobility (Toolbox) is to pro- costs to the community when the strategies that can be used to vide local elected officials, business transportation system does not pro- leaders, and community leaders with vide the level of performance desired. provide Improved mobility and information on the congestion phe- In addition, this chapter presents an accessibility. nomenon and on the multimodal overall framework for developing a transportation strategies that can be coordinated program to provide good used to provide improved mobility multimodal transportation service to a and accessibility. There are ways of community. Chapter 2 discusses dealing with traffic congestion prob- actions that can be implemented to lems. Some actions can be used indi- enhance the person-carrying capabili- vidually, while others require mutually ty of the highway system, without supportive actions implemented coop adding significantly to the width of eratively by several public and private the highway. Chapter 3 discusses sector groups. Some actions focus actions that result in substantial exclusively on changes to the trans- added capacity to the highway system, portation system, while others deal either through the widening of exist-
TRAFFIC CONGESTION AN OVERVIEW ing roads or by constructing new sense, a congested facility is just one highways. Chapter 4 discusses public element of a transportation system’s transportation actions that can be ability to provide mobility and acces- used to move people more effectively. sibility. Delays at particular locations Chapter 5 discusses actions for reduc- in a transportation network are ing transportation demand either certainly aggravating to those using through land use management, region- the system, but these delays are part al demand management programs, or . of a much larger picture of how a site-specific policies like carp001 pro- transportation system allows people grams. Chapter 6 presents an overview and goods to move around a metro- of new applications for advanced tech- politan area. nologies in providing transportation To some, congestion is not a services. Chapter 7 discusses funding problem. It is considered to be one and institutional actions that can be . result of economic prosperity and used by themselves or in combination one that we will have to learn to live with other actions. with. Proponents of this viewpoint To some, congestion IS considered to be one result of economic prosperity Others argue that our expectations about argue that the consequences of congest/on are much more serious to a community convenient travel will simply have to change. Others argue, however, that Chapters 2 through 7 are struc- the consequences of congestion are tured to provide the reader with easi- much more serious to a community. ly accessed and understood informa- Those holding this viewpoint have tion about specific actions. Sections often relied on one or more of the within each chapter present: following arguments:
1) a brief description of the action Local Traffic Impacts: When faced with special attention given to the with congested conditions, many criteria for success, drivers quickly look for ways to bypass the bottleneck. These often 2) the costs and benefits/impacts of include making their way through the action that have been deter- residential neighborhoods on streets mined from previous experience, not designed to handle through 3) steps needed to implement the traffic. Such bypass traffic often action successfully, and becomes the focus of neighborhood 4) sources of further information on complaints. Similar complaints are the action. often heard when overflow parking finds its way into neighborhoods. WHY WORRY Economic Growth: Efficient trans- Put simply, traffic congestion means portation access to employment and there are more people trying to use shopping sites is an important consid- a given transportation facility during eration to businesses and developers a specific period of time than the when considering expansion opportu- facility can handle with what are nities. A good transportation system considered to be acceptable levels of is an important selling point to delay or inconvenience. In a broader communities that desire to attract
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY development. In addition, good Environmental Quality: Congested transportation is very important to road conditions can have a detrimen- the movement of goods and services tal effect on the environment, in par- and thus has a direct impact on ticular, air quality. Making improve- sound economic growth and produc- ments to the transportation system or tivity (Transportation Research Board trying to change travel behavior has 1995). been an important objective of those wanting to improve environmental Community Access: Good access quality. within a community and to other parts of the metropolitan area by These arguments can be important drivers and by those using public reasons for being concerned about transportation is an important issue the performance of the transportation to community residents. Not only is system. However, of even more inter- good access important to those est to community leaders, addressing looking for places to live, but it can the mobility needs of a community become an important community has become in several cases a litmus public safety (e.g., police, fire and test for effective leadership. Because emergency medical) issue. the public sector is viewed as having the major responsibility for solving Quality-of-Life: To some people, transportation problems, community congested highways are a symptom officials are often the focal point for of deteriorating quality-of-life in a citizen unrest concerning traffic con- Addressing the mobility needs community. In many cases, and in gestion and mobility needs. particular in suburban communities, of a community has become In Transportation as a Regional Issue: residents moved to their community several cases a litmus test for to escape urban problems like traffic In addition to the local concerns effective leadership jams. Now, facing this congestion has identified above, there are metropoli- once again become part of their daily tan-level planning requirements and routine. Another aspect of this quali- federal (and often state) environmen- ty-of-life characteristic is the role tal laws that require a comprehensive transportation plays as a key element examination of congestion reduction of getting and keeping a job. This is and mobility strategies. For example, particularly important today with the the Intermodal Surface Transporta- greater emphasis being given to tion Efficiency Act (ISTEA) passed “welfare-to-work,’ programs. and amended by Congress requires that all states and metropolitan areas Highway Safety: Whether charac- have a transportation planning terized by stop-and-go traffic along process that considers these types of a major road or by traffic trying to strategies. For metropolitan areas over get through intersections, congested 200,000 population, and especially highways often can result in acci- those not in attainment of air quality dents. Reducing this congestion standards, a congestion management could reduce the number of accidents system is required that identifies and generally produce safer travel strategies for improving the perfor- conditions. mance of the transportation system
TRAFFIC CONGESTION AN OVERVIEW with special consideration given to Milwaukee: In 1991, the number he pollution-reducing impact of of vehicle miles of travel on an these strategies. The transportation average weekday totaled nearly 33 planning and project programming million/53 million kms. Under a process in non-attainment areas is no-build alternative, the growth in very much influenced by this assess- vehicle miles traveled would be a-rent. Therefore, understanding what approximately 35 percent to 44.5 strategies are available in the Toolbox million vehicle miles/72 million kms and their likely impacts on travel of travel in the year 2010 (Southeast behavior and air quality becomes a Wisconsin Regional Planning critical input into the planning Commission 1995). process in many of our major Boston: Vehicle miles traveled in metropolitan areas. This is especially 2020 are forecast to increase by important if one looks at the expect- approximately 25 percent...Vehicle ed levels of congestion on urban hours of travel are forecast to grow by transportation systems in the near 35 percent in the base case, evidence future. of growing systemwide congestion TRANSPORTATION TODAY (Central Transportation Planning AND TOMORROW staff 1993).
Increasing levels of congestion are Albany: Congestion-related delay common in urban areas throughout will increase significantly for the the United States. Recent transporta- region as a whole by 2015. This con- tion plans for a sample of urban areas gestion will be experienced dispropor- and states indicate some of the char- tionately-suburban areas will experi- acteristics associated with future ence a growing percentage of the mobility challenges: region’s congestion (Capital District Florida: Daily vehicle miles traveled Transportation Commission 1995). has continued to grow, from 300 mil- Atlanta: . ..despite substantial lion miles1483 million kms in 1990 to improvements to the highway system, 334 million miles/538 million kms in over 53 percent of the vehicle miles 1994, an increase of about 11 percent traveled in 2010 will be on facilities (Florida DOT 1995). that are subject to levels of service F Dallas-Ft.Worth: The growth in (Atlanta Regional Commission vehicle miles of travel and vehicle 1990). miles of travel per person in the Texas: Increased congestion on region represents a significant chal- Texas’ highways will worsen signifi- lenge in addressing mobility needs of cantly over the lifetime of the the region. By the year 2010, daily Plan---twice as many miles of major vehicle miles traveled is projected to urban facilities will be congested in exceed 124 million/200 million kms 2012 than were in 1992, causing representing a 33 percent increase in delays on more than half of urban travel (North Central Texas Council . Interstate, freeway, and expressway of Governments 1995). miles (Texas DOT 1994).
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY
The number of Highway Administration 1993). workers in the labor force almost This increase can be associated with doubled between 1950 and 1990, the tremendous population and with women joining the labor force employment growth in the suburban being a major reason for this signifi- areas of our metropolitan regions cant increase. Importantly, the (86 percent of total U.S. population increase in workers by geographic growth since 1970 had occurred in area illustrates the suburbanization the suburbs), and in the rising per- that has occurred in every U.S. met- centage of the adult population who ropolitan area. From 1980 to 1990, had drivers licenses. 65 percent of the growth in the labor Households by Vehicles Available: population occurred in the suburbs, Although population and number of 18 percent in the central city, and 17 households between 1980 and 1990 percent in non-metropolitan areas. increased by less than 10 percent and The suburbs in 1990 had 42 percent 14 percent, respectively, the total of the nation’s jobs (up from 37 per- vehicles available to households grew cent in 1980), and suburban areas by over 17 percent. Every worker has saw 49 percent of the growth in jobs on average 1.3 vehicles available for from 1980 to 1990, whereas central the work trip. Over the past decades, cities represented only 23 percent of the number of households with multi- the growth. ple vehicles grew rapidly. Households and Persons/Household: Licenses: Between 1969 and 1990, Between 1969 and 1990, the number the number of licensed drivers in the of households grew 49 percent with United States increased by almost 60 the largest share of the growth in sin- percent. For those aged 30 through gle-person and single-parent house- 49, over 96 percent of the men and holds. The average household size roughly 93 percent of the women are also declined from 3.16 persons in licensed. In addition to licensed dri- 1969 to 2.56 persons in 1990. This vers, the number of automobiles phenomenon has had profound available for trip making increased implications on transportation in that significantly. Between 1969 and each household has a baseline 1990, the average number of vehicles amount of trips and travel associated per household rose from 1.1 to 1.77, with it (Federal Highway Admini- with only 9.2 percent of U.S. house- stration 1993). holds not having a car available for a Trips/Capita: Between 1983 and trip (one in five households had three 1990, trips per capita increased by or more cars). almost 7 percent to 3.04 trips per Mode Use: Transit’s share of all male and 3.13 trips per female. national travel has declined to about Person Trip Length: The average 2 percent, although in many urban miles for commuting each day in markets transit retains a strong pres- 1983 was approximately 7.9 miles/ ence. This decline is associated with 12.7 kms; in 1990 this number had increased auto availability to those risen to 9.55 miles/15.4 kms (Federal population groups most likely to use
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY transit and the continued suburban- l The elderly population will be ization of metropolitan regions result- growing more rapidly than the pop- ing in land uses difficult to serve with ulation in prime driving age groups. traditional transit services. However, the differences in travel demand between younger people Auto Occupancy: Average vehicle and seniors will be narrowing. occupancy (measured as person miles per vehicle mile) has declined from l The image of seniors traveling by 1.9 in 1977 to 1.6 in 1990. In many bus or on foot to take care of their urban highway corridors, the average daily needs is no longer accurate. automobile occupancy for work trips More seniors will be driving well is below 1.1 persons per vehicle. into their retirement years. The number of person miles All of these factors have con- . More people living beyond age 75 tributed to a fundamental characteris- will result in more trips taken by traveled and the number of younger family members to help in tic of the urban travel phenomenon trips made have increased -the number of person miles trav- their care. eled and the number of trips made proportionately much faster There will be a continued diver- have increased proportionately much . gence in travel behavior between than the individual factors that faster than the individual factors that men and women. influence trip-making influence trip-making. Married men with children, What does the future hold? A . regardless of the age of their recent report from the Urban Land youngest child, make the same Institute which examined some of the number of trips as married men underlying causes of congestion iden- without children. tified the following trends and obser- vations that could affect future urban l The use of transit and carpooling is travel: (Dunphy 1997) declining more so for women than for men. . Growth in the United States popu- lation is slowing, but millions of l Race and ethnicity further differ- added travelers will still need to be entiate travel patterns. accommodated. . Wealthier households make more . Virtually all Americans old enough trips, use cars more, and travel to drive are already licensed. longer distances.
l In the U.S. there already is more l Low density development means than one car, van, or light truck more automobile trips. for every person age 16 and older. l Nonwork travel will increase as a l Looking ahead to 2010, the num- share of total trips. ber of young adults will return to . Dispersed development means its 1980 level, from a recent more shopping trips, while decline. increased catalog and electronic . Baby boomers will make up a shopping will mitigate against this smaller share of the population by trend. 2010.
TRAFFIC CONGESTION AN OVERVIEW l Cities are capturing a decreasing considered in dealing with congestion share of new jobs, resulting in and mobility. Multimodal transporta- longer work trips and lower public tion system performance more than transit ridership. ever now includes an integrated mul- timodal perspective for overall mobil- During the 1990s cities will not be . ity and accessibility. The three terms as successful as they were in the that will be used in this version of the 1980s in slowing the rate of exodus Toolbox are defined as: (Meyer, 1996) of jobs to the suburbs. The shift of jobs to edge cities means quicker Mobility: The ability and knowledge commutes for suburbanites, more to travel from one location to anoth- travel for lower-income city resi- er using a multimodal approach. dents, and lower transit demand. Accessibility: The means by which l The dispersal of employment an individual can accomplish some centers means more commuting economic or social activity. between suburbs and across county Congestion: The travel demand for lines. a facility or service exceeds the . Growth in the labor force is slow- capacity of that facility/service to ing. More people are holding two handle the demand at performance or more jobs. levels considered acceptable to facili- ty/service users. . More companies are offering flexible work hours as an employee Note that this definition includes perk and to reduce peak hour not only highway facilities, but also traffic. Telecommuting and transit services. Also, in these defini- working at home are increasingly tions, “mobility” implies movement, popular options. but accessibility does not. For exam- ple, modern telecommunications MOBILITY ANDACCESSIBLI THE BIGGER PICTURE allows one to order goods and/or con- duct work without ever leaving The original Toolbox published in home. The activity is accomplished, 1989 focused on strategies and but the individual does not have to actions that were aimed at relieving use the transportation system to congestion on the transportation sys- achieve the objective. In fact, one of tem with primary focus on the high- the more recent strategies for reduc- way system. Most often, this conges- ing congestion is to encourage tion occurred at specific locations telecommuting so that accessibility to and were, in many ways, just one ele- the workplace still occurs, but vehic- ment of the total trip for people and ular travel is reduced. This broader goods in a metropolitan region. Since perspective on improving the perfor- passage of the Intermodal Surface mance of the transportation by devel- Transportation Efficiency Act in oping a coordinated mobility program 1991, many transportation officials for your community system is further have broadened their perspective on illustrated later in this chapter. the types of strategies that can be
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY CAN ANYTHING BE DONE? “supply” of transportation), from the perspective of those who use The simple answer to this question is, these services (i.e., better manag- “yes”! There are proven techniques ing the “demand” for the trans- that can be used to deal with specific portation system), from the per- congestion problems, as well as trans- spective of influencing where this portation and land use strategies that demand occurs (i.e., the land use can be implemented to enhance dimension), or any combination of mobility and accessibility. The more the above. difficult answer to this question is, “Yes, but . ...”Many of these tech- l Consider carefully how individual niques and strategies require changes actions relate to one another and in individual travel behavior, persua- how, when combined into an over- sive use of land use management all program, they relate to regional techniques, changes in institutional and community objectives. structure, garnering of political will, l Implement those actions that and/or increased funding. This is par- through sound engineering and titularly true for those strategies . planning analysis are shown to aimed at a longer term vision of improve congestion problems in a Many of these techniques and improved mobility and accessibility. cost effective, multimodal manner. strategies [that address congestion Given this perspective, what can be Be realistic in the assessment of done? what is likely to be accomplished. problems] require changes in
l Recognize that traffic congestion is individual travel behavior; persua- l Recognize early on that the imple- a more difficult problem than sim- mentation of actions that are like- sive use of land use management ply too many cars at a particular ly to be controversial will require techniques, changes in institutional location. There are institutional strong commitments and efforts at and land use dimensions to the developing a constituency for the structure, garnering of political problem that make it complex. In action from interested organiza- will, and/or increased funding. addition, congestion is simply a tions that have not traditionally symptom of much larger issues been part of the transportation associated with mobility and acces- planning process. sibility in a community. l Incorporate private sector interests l Recognize the direct and funda- . (developers, employers, business mental relationship between land associations, etc.) into the plan- use and travel patterns. Approving ning and decision-making process. land developments without It is often in their best interest to providing adequate transportation participate, and they can provide options will result in congested, strong support in gaining project unsafe, and environmentally or program adoption. damaging conditions. l Cooperate with neighboring gov- l Recognize that transportation ernmental jurisdictions, regional improvements can be considered transportation agencies, and orga- from the perspective of enhanced nizations that provide transporta- transportation services (i.e., the
TRAFFIC CONGESTION: AN OVERVIEW
Second, a mobility/congestion reduc- enhanced ridesharing activities into tion program should examine better the design and use of the site (a land ways of managing transportation use/development decision). Similarly, demand, especially if the opportunity linkages exist between different tools for substantial gains in system that often work at cross purposes. For mance through expansion or opera- . example, land development regula- tional improvements is limited. tions that require high minimum lev- Third, a mobility/congestion reduc- els of parking as a condition of devel- tion program should explicitly con- opment work against employer sider long-range strategies that will demand management programs. A provide the foundation for avoiding mobility and congestion reduction similar problems in the future. This program must therefore consider how implies an important role for consid- each action relates to one another. ering future land use/development The important components of a patterns and their impact on travel. mobility/congestion reduction pro- Finally, the program needs to deal gram are shown in Figure 1-2. Note with institutional arrangements and that a key word that is used to funding requirements for implement- describe each component is “manage- ing the program. This is especially ment.” Because much of our trans- important where the transportation portation system is in place, the deci- services are housed in separate units. sions of what additional capacity to In most cases, substantial levels of provide, what types of operational funding will be necessary to provide improvements to make, how to influ- the desired levels of mobility and/or ence demand for the purpose of congestion relief. However, there are a number of cost-effective improve- Figure 1.2: Elements of a Mobility/Congestion Reduction Program ments that can be implemented at low cost, including improvements Intelligent Transportation Systems A Planning & Zoning using intelligent transportation sys- tern (ITS) technologies. Transit Facilities and Services Phasing/Adequacy Intermodal Facilities Even though these program com- ponents are listed separately, they are Traffic Engineering
really complementary to one another. Highway Capacity Density For example, a ridesharing program Bike/Walkways (an effort to influence demand) can become more effective if some form of preferential treatment is provided en route (e.g., a high occupancy vehi- DEMAND MANAGEMENT cle lane) or at the destination (e.g., Alternative Work Alternative Alternative Work Employer Support preferential parking), both changes to Schedules Modes Locations the transportation system. The effec- . tiveness of the ridesharing program Financial Incentives and Disincentives could be even greater if employers were required to incorporate Source: Meyer
TRAFFIC CONGESTION AN OVERVIEW reducing the impact of traffic, how to engineering improvements such as develop compatible land use, and turn lanes, one-way streets, reversible how to provide the institutional and lanes, and turn prohibitions; the addi- funding structure that supports the tion of new transit services or improv- program are all in essence system ing existing service by adding vehi- management decisions. cles, increasing vehicle size, or increasing frequency of service; the Figure l-2 is an important point of provision of preferential treatment to departure for developing effective those who use multi-occupant vehi- mobility/congestion reduction pro- cles; and ramp metering are Illustra- grams. Significantly, this figure sug- tive of the types of actions that can be gests that to be effective, such a pro- used to deal with congestion problems gram should consist of actions or that occur every day. Increasingly, toolsthat come from three different transportation professionals are also categories-managing the supply of becoming interested in those actions the transportation system, managing such as incident detection programs, the demand or travel behavior of motorist information systems, and those who use transportation, and towing/enforcement efforts that can managing the land use and/or devel- be used to minimize the effects of opment patterns that influence when accidents and other non-recurring and where travel demand occurs. incidents on traffic flow. Advanced Every community’s mobility/conges- transportation technologies, known as tion reduction program falls some- intelligent transportation systems where inside the shown triangle. In (ITS), are also being considered seri- some cases, a community might rely ously as tools to reduce congestion more on transportation demand and and enhance mobility. land use actions to provide improved Because planners and engineers mobility, whereas others might place have had many years of experience greater emphasis on expanding the with the supply side of the trans- capacity of the transportation system. portation system, there is more evi- Each community must decide dence in the literature on the impact through its planning and decision- of these types of actions. In the making process where inside the tri- extreme, that is, where new capacity angle it wants to be. can be continually added to accom- Managing Transportation System modate the demand, these actions Supply-Managing the transportation can significantly reduce congestion system by adding new facilities or by levels. In the long term, however, this making operational changes to additional capacity, if assigned to improve system performance has been highway improvements only (e.g., the most common response to trans- additional lanes), will continue a portation problems for many years. heavy reliance on the automobile Actions such as the construction of which could have serious implica- new highways and transit facilities; tions to some on the urban mobility the provision of improved traffic sig- options available in the region. On nalization schemes; the use of traffic the other hand, additional capacity
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY improvements to transit could help large employment centers--but they alleviate the congestion problem. In cannot appreciably reduce traffic on heavily urbanized areas, the construc- freeways and major arterials. The tion of these actions (especially major only exception to this seems to be highway improvements) can be cost- areawide road pricing schemes which ly, their implementation met with at least from a modeling perspective strong opposition, and even if feasi- indicate significant influence on trav- ble, they might take a long time to el demand. One should therefore be complete. It is for these reasons that careful not to raise unrealistic public
other actions need to be considered. expectations as to their impact on Available evidence suggests that areawide levels of traffic congestion. Managing Transportation well-conceived and aggressively Demand-In its broadest sense, Managing Land Use-One of the demand management is any action or fundamental relationships in under- promoted demand reduction set of actions intended to influence standing how and why the trans- programs can indeed decrease the intensity, timing, and spatial portation system operates is the peak period traffic at many sites distribution of transportation demand linkage between land use and trans- for the purpose of reducing the portation. Put simply, trip-making by as much as 10 to 15 percent. impact of traffic or enhancing mobili- patterns, volumes, and modal distrib- ty options. Such actions can include utions are largely a function of the offering commuters one or more spatial distribution and use of land. alternative transportation modes Thus, at individual development and/or services, providing incentives sites, exercising control over the trip to travel on these modes or at non- generating characteristics of the land congested hours, providing opportu- use (e.g., development density) can nities to better link or “chain” trips be used to make the resulting demand together, and/or incorporating growth consistent with the existing trans- management or traffic impact policies portation infrastructure and the level into local development decisions. of service desired. Available evidence suggests that Over the long run, the spatial dis- well-conceived and aggressively pro- tribution of land use can greatly influ- moted demand reduction programs ence regional travel patterns, and in can indeed decrease peak period traf- turn this land use distribution can be fic at many sites by as much as 10 to influenced by the level of accessibility 15 percent. In fact, as will be provided by the transportation described in chapter 5, significantly system. Changing the economic higher demand reduction levels have equation for travel by equalizing been achieved at several employment subsidies for all modes could also sites. But one should be careful to affect location decisions. Avoiding understand the limitations of this future congestion therefore requires technique. Demand reduction efforts, careful attention to zoning and land unless undertaken on a truly massive use plans, in coordination with the scale, can have only a local impact. strategic provision and pricing of They can relieve spot congestion- transportation services to influence for example, at entrances and exits to where development occurs.
TRAFFIC CONGESTION AN OVERVIEW Managing the Institutional and perspectives’on responsibility, fund- Funding Framework-Implemen- ing, and decision-making authority, tation of individual actions or combined with differing expectations combinations of actions is often con- of project timing and outcomes, can strained by institutional problems lead to frustration in dealings associated with the coordination of between the two sectors. However, many groups in both the public and effective mobility/congestion reduc- private sectors. The authority for tion programs require the active par- transportation decision making is ticipation and support of private sec- dispersed among several levels of gov- tor groups. Therefore, successful pro- ernment and often between several gram implementation will be in large agencies within each governmental part due to the success that project level. The areawide nature of travel proponents have in managing the requires a regional or subregional institutional characteristics of deci- framework of decision making. sion-making and project implementa- In some metropolitan areas, the tion in the public sector and among challenge created by today’s trans- public and private sector participants. portation problems has resulted in Adequate funding is an important aspect of any congestion reduction Given that not much can happen without funding, managing the process of action or mobility program. In those cases where actions are more local obtaining the required resources and then effectively managing the operating and site-specific, acquiring the neces- and capital budgets that result, is the most critical aspect of a comprehensive sary funding will be a matter of pro- mobility congestion reduction program gramming the project in the capital budget of the responsible agency or of transportation agencies re-examining getting commitments from other their mission and function. For exam- sources (e.g., developers or business ple, many transit agencies are associations). In addition, many mar- responding to the new, non-tradition- ket-based strategies can generate rev- al suburban markets with new types . enues for use in improving the trans- of services. Transit agencies are portation system. At the regional viewing themselves as “managers of level, adequate funding could require mobility” rather than just operators special assessments or taxes that of traditional bus or rail services. In would be allocated for this purpose. other metropolitan areas, subregional Such funding will most likely require planning groups have been formed to serious political deliberation and deal with transportation problems. voter approval. Given that not much The increased role of the private can happen without funding, manag- sector in dealing with transportation ing the process of obtaining the issues has often introduced added required resources and then effective- complexity into the institutional ly managing the operating and capital structure for decision making. Diverse budgets that result, is the most criti- cal aspect of a comprehensive mobili- ty/ congestion reduction program.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Figure 1.3: A Toolbox for Reducing Congestion and Enhancing Mobility
All of the mobility/congestion reduc- tion actions that are presented in the rest of this Toolbox should be consid- INSTITU ered as “tools” that can be used by AND FU local officials to develop a compre- ENVIRO hensive program for dealing with the transportation problems they face. Similar in concept to the tools that are used to make repairs around the house, these tools, both individually INSTITUTIONAL and in different combinations, can be AND FUNDING ENVIRONMENT used to “fix” transportation problems. For purposes of presentation, assume that these tools are available in a tool depends on the institutional and toolbox. As shown in Figure l-3, this funding environment specific to that toolbox has four different compart- tool. The challenge to the user of a ments. In come cases, the nature of toolbox of course is to know which the congestion/mobility problem tool or combination of tools to use in would require tools that deal with a particular situation. Effectively HAN- changes to transportation supply and dling a mobility problem may simply which require a short (one to three require some combination of high-
years) timeframe to implement. way, transit improvements, and land Once a drawer is opened, the Other drawers in the toolbox contain use/development policies (e.g., higher tools that also deal with transporta- . density levels for new sites) in a spe- effectiveness of that particular tion supply but which require a cific corridor. In fact, as noted previ- congestion reduction tool longer timeframe to implement. In ously, the areawide nature of travel depends on the institutional addition, the toolbox contains tools will usually require some combination that try to influence transportation of tools and thus different sections of and fundrng environment demand over both the short- and this document. What is needed then specific to that tool. long-term. is a better understanding of the BENE- fits and costs of each tool available to The remaining chapters of this community officials and the effect book provide the contents of these that these tools have when combined drawers. Figure l-3 is also an example into packages. of how this toolbox (and the remain- der of this book) can be used. Note that each drawer contains informa- tion on that particular mobility/con- gestion reduction action, its benefits and costs, and the requirements for successful implementation. Once a drawer is opened, the effectiveness of that particular congestion reduction
TRAFFIC CONGESTION AN OVERVIEW INTELLIGENT TRANSORTATION port other strategies (e.g. user ser- SYSTEMS vices that support ridesharing and One of the new “tools” in the Toolbox transit operations). is the application of intelligent trans- . ITS strategies interact with other portation technologies to the transportation strategies in impact- improved management of the trans- ing traffic congestion and mobility portation system. Intelligent trans- (e.g. an HOV ramp meter bypass portation systems (ITS) are defined system needs to interact and coor- as “the application of advanced sen- dinate with the provision of transit sor, computer, electronics, and com- Nine key ITS infrastructure service and ridesharing efforts). components have been identified munications technologies and man- l ITS may sometimes need to be as being essential to traffic man- agement strategies-in an integrated considered as a competing alterna- agement and traveler information manner-to increase the safety and tive with other transportation services within a metropolitan efficiencyof the surface transporta- strategies. area. tion system.” The basic premise of ITSis that by integrating different 1. Regional Multimodal . In a planning environment with Traveler Information Systems system components and technologies constrained resources, ITS needs in a consistent fashion, great benefits to be considered for its investment 2. Traffic Signal Control Systems can occur. ITS applications can occur merits along with other strategies. 3. Freeway Management for both highway and transit opera- There are elements of ITS that are Systems tions, such as freeway and arterial . unique and that need to be consid- management, interconnected traffic 4. Transit Management Systems ered at a regional level indepen- signals, areawide traveler information 5. Incident Management dent of other transportation strate- services, electronic toll collection, Programs gies in establishing cost-effective and transit automatic vehicle loca- systems. For example, a communi- 6. Electronic Toll Collection tion. The key vision for ITS is that cations system or traveler informa- Systems such technologies will provide a core tion system should be thought 7. Electronic Fare Payment communications network, transporta- through at a regional level to pro- Systems tion system monitoring, and vide for economies of scale, consis- advanced information processing 8. Railroad Grade Crossing tency among geographic areas, and capabilities that can act as a founda- Warning Systems coordination among agencies. tion for the coordinated operation of 9. Emergency Management the transportation system. Given the operational focus of Systems many ITS actions, the consideration The appropriate role for ITS in the of ITS in transportation planning context of transportation planning might very well provide an important includes: operations orientation to the trans- . ITS can represent both direct portation plans and programs that operational initiatives (e.g. freeway result from the planning process. and network traffic control systems and incident management sys- tems) as well as actions that sup-
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY
estimated at $1 .l billion. The study ly, a great deal of professional atten- concluded: tion has been paid to the economic benefits of improvements in trans- l The Seattle region spends a portation services. These benefits can “staggering” amount of money on be associated with additional business transportation, about 25 percent of or industry attracted to a location, the region’s personal income. increased tourism, and expansion of l Public expenditures on roads, existing businesses due to decreased transit, and ferries represent only Some methods only take into transportation costs (Weisbrod and 8 percent of all transportation Beckwith 1992; Wilbur Smith and consideration those benefits and expenditures Assocs. 1993). For transit services, costs that are linked to those l Even without considering gas benefits have been. defined along many different dimensions-those directly affected by a project taxes, licensing, and excise taxes, auto-related expenditures by improvements to transit riders in the Others argue that a fair accounting individuals and businesses repre- form of reductions in time, cost and of benefits and costs should sent 62 percent of all expenditures. inconvenience; changes in well-being and security, changes in lifestyle, and l Less than 3 percent of the region’s consider all direct and indirect improvements to the natural environ- direct public and private trans- impacts and take into considera- ment (Beimbom and Horowitz 1993). portation expenditures go toward tion the total costs to society of transit, ferries, and non-motorized The estimation of costs is often more complex than simply adding the inplementing a particular project transportation. amount of dollars needed to construct These distinctions on how one . a project. Importantly, monetary costs estimates benefits and costs are should be considered over the entire important in that many debates on life cycle of a project to obtain a bet- the cost effectiveness of individual ter picture of how much a project will projects depend on what type of cost when considering not only actu- benefit or cost is being considered. al construction, but also operations, Some methods only take into consid- maintenance, and rehabilitation. eration those benefits and costs that Total societal costs of a project might are linked to those directly affected include costs associated with conges- by a project. Others argue that a fair tion, air pollution, noise and water accounting of benefits and costs pollution, loss of biological diversity, should consider all direct and indirect accidents, and energy consumption. impacts and take into consideration In this document, the costs reported the total costs to society of imple- for typical application of the tools are menting a particular project. primarily construction or purchase The traditional benefits relating to costs. Users of the Toolbox, however, such improvements usually reflect the when considering the implementa- cost savings to users and to society of tion of different actions should care- reductions in travel time, vehicle fully weigh a full cost accounting of a operating costs, fleet management project’s impacts. costs, ease and convenience of use, and accidents. However, more recent-
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY COMMITMENT, PROCESS One of the ways of gaining support AND PUBLIC INVOLVEMEN for these actions is to involve the Tools are not very helpful if one does public in the discussion and debate not know how or is unwilling to use that precedes adoption. Some of the them. Many of the tools in this most successful efforts at adopting Toolbox, especially those that attempt transportation programs have exhibit- to influence demand, require time for ed the following characteristics: their full effect to occur. For example, l Waging an aggressive campaign to a major purpose of preferential lanes inform the public of what is likely for high occupancy vehicles on major to occur if something is not done. freeways is to encourage the increased Clearly stating what the average use of transit and ridesharing. For this . citizen will gain from these to happen in any significant way actions. might have to await land use and travel behavior changes that could l Providing opportunities for citizens take years. In the meantime, incon- and interest groups to participate venience to existing users of the free- in the planning and decision-mak- Officials must have a strong way could result in political pressure ing process. commitment to the implementa- to remove the lane. Officials must Actively pursuing business support have a strong commitment to the . tion of these types of techniques for the proposed actions. implementation of these types of if they are ever to be effective. techniques if they are ever to be . Seeking media support in editorials effective. and news reporting. l Developing a cost effective pro- gram that appeals to as broad a political base as possible.
There are many examples from around the country where good ideas and projects have languished for years. In some sense then the process of implementing mobility/congestion reduction actions is as important as the actions themselves. It is for this reason that a focus on implementa- tion is provided for each tool described in this Toolbox.
TRAFFIC CONGESTION AN OVERVIEW References Apogee Research, Inc. 1994 “Cost Benefit Analysis of Hi&way Improvement Projects,” Prepared for the Federal Highway Administration, Washington D.C., October. Atlanta Regional Commission. 1990. Atlanta Regional Transportation Plan: 2010, Atlanta, GA, March. Beimborn, Ed and Alan Horowitz.1993. ‘Measurement of Transit Benefits,” Report DOT- T-93-33, Urban Mass Transportation Administration, Washington, D.C., June. Capital District Transportation Committee. 1995. Community Quality of life: Measurements, Trends, and Transportation Strategies, Albany, NY, August. Central Transportation Planning Staff. 1993. The Transportation Plan jii the Boston Region, Boston, MA, November. Dunphy, Robert. 1997. Moving Beyond Gridlock, Traffic and Development, Urban Land Institute, Washington D.C. Federal Highway Administration. 1993. Travel Behavior Issues in the 90’s, Report FHWA- PL-93-012, Washington D.C. Florida Department of Transportation. 1995. Implementing the 2020 Transportation Plan, 1996-2005, Tallahassee, FL, April. Gomez-Ibanez, Jose. 1995. "Pitfalls in Estimating Whether Transport Users Pay Their Way,” Paper presented at a Conference on Measuring Full Social Costs and Benefits of Transportation, Bureau of Transportation Statistics, U.S. Department of Transportation, Washington D.C., July. Meyer, Michael. 1996. alternative Performance Measures Fur Transportation Planning: Evolution Toward Multimodal Planning, Federal Transit Administration, Report FTA- GA-26-7000, Washington D.C., December North Central Council of Governments. 1995. Mobility 2010 Plan Update, Technical Findings, Arlington, TX, September. Pisarski, Alan. 1996. Commuting in America II, Report prepared for the Eno Transportation Foundation, Inc., Washington D.C. Puget Sound Regional Council. 1996. The Costs of Transportation, Expenditiures on Surface Transportation in the Central Puget Sound Region for 1995, Seattle, WA. Southeast Wisconsin Regional Planning Commission. 1995. I994 Annual Report, Milwaukee, WI, August. Texas Department of Transportation. 1994. The Texas Transportation Plan, Modal Profiles, Austin, TX. Transportation Research Board. 1995. Congestion Impacts on Business and Strategies to Mitigate Them, Research Results Digest No. 202, Washington D.C., September. Weisbrod, Glen and James Beckwith. 1992. “Measuring Economic Development Benefits for Highway Decision-Making: The Wisconsin Case,” Transportation Quarterly, January. Wilbur Smith Associates. 1993. “Guide to the Economic Evaluation of Highway Projects”, Prepared for the Iowa Department of Transportation. U.S. Department of Transportation. 1996.1995 Status of the Nation’s Surface Transportation System: Condition & Performance, Report to Congress, Report FHWA-PL- 96-007, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY IN THIS CHAPTER . . .
Urban Freeways
· Freeway Incident Detection and Management Systems · Ramp Metering · Highway Information Systems · Freeway Corridor Traffic Management (including Arterial Surveillance and control) · Providing Additional Lanes without Widening the Freeway · High Occupancy Vehicle (HOV) Facilities · Park-and-Ride Facilities · Highway Pricing Strategies
Arterials and Local Streets: Design
· Super Street Arterials · Intersection Improvements · One-Way Streets · Reversible Traffic Lanes · Arterial Access Management · Traffic Calming and Street Space Management
Arterials and Local Streets: Operations
· Traffic Signal Improvements · Computerized/Interconnected Signal Systems · Arterials Surveillance and Management · Turn Prohibitions · Improved Traffic Control Devices
Arterials and Local Streets: System Management
· High Occupancy Vehicle (HOV) Facilities on Arterials · Parking Management · Freight Movement Management · Bicycle and Pedestrian Networks
Enforcement
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM
This chapter is organized in five major sections. The first focuses on those actrons that are primarily oriented to better managing urban freeways or expressways..
The second, third and fourth sections describe actions that relate to the design, operations, and system management of arterial and local streets. The last section in
the chapter discusses the important role of enforcement.
As indicated in Chapter 1, highway known as non-recurring congestion. congestion will grow substantially By some estimates, as much as 60 worse in the years ahead unless the percent of all freeway congestion is total transportation system is considered to be non-recurring. Thus, improved to handle mobility a key strategy for reducing congestion demands. In some cities, these in major urban areas is to handle improvements will include the con- accidents’ and incidents as quickly as struction of new highways. However, possible to keep traffic flowing. in these and other cities, local officials The approaches discussed in the will be greatly interested in what following sections will describe the improvements to the existing highway potential of reducing one or both system can be made before more cost- types of congestion. ly and potentially more disruptive Highway congestion will grow substantially worse in the ahead unless the highway construction might occur. years This chapter thus focuses on the total transportation system is improved to handle mobility demands. highway element of transportation systems management. This chapter Freeway Incident Detection and Management Systems presents cost effective improvements that can be made to existing freeways Description: Accidents (and other and arterials in a relatively short incidents) are a common occurrence timeframe, and in many cases, at a on urban freeways. As shown in relatively low cost. Figure 2-1, between 80 to 85 percent of recorded incidents are vehicle dis- ( URBAN FREEWAYS ) ablements, 5 to 10 percent are acci- Although urban freeways make up less dents, and the remaining percentage than 2.4 percent of the total urban includes emergency maintenance highway mileage, they carry approxi- work, debris on the road, etc. mately 20 percent of the traffic (Cambridge Systematics and The nationwide. Congestion on this road- ATA Foundation 1996). There are way system can occur under recurring three major stages to an incident conditions (i.e., due to capacity or management program: 1) detection/ operational problems) or can be verification, 2) response/clearance, caused by accidents or breakdowns, and 3) recovery/information.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
A study of a freeway service patrol Developing a comprehensive in the San Francisco Bay area con- freeway incident management strate- cluded that the proportion of tow gy is one of the most cost effective truck assisted incidents increased from strategies that can be implemented 9 percent “before” to 24 percent after as part of a transportation system implementation with 80 percent of management program. As shown in these assists provided by the patrol Figure 2-3, the different types of (Skabardonis et al 1995). About 30 actions that can be undertaken to percent of these incidents required provide better incident management the vehicle to be removed from the capabilities can vary in potential highway. The response times of the benefits and costs. service patrol assists were reduced by Implementation: The documented 57 percent, and the response times of impacts of freeway incident manage- all assisted incidents were cut by 35 ment improvements have been percent. This service had an estimat- impressive. As freeways become more ed benefit/cost ratio of 3.4:1 and an congested, incident detection and estimated annual reduction of 77 tons management systems will become of carbon monoxide, 19 tons of oxides even more important. The process of nitrogen, and 7.6 tons of hydrocar- from conceptual planning to com- bons. A survey of motorists assisted pleted system in an urban area can by this service not surprisingly showed take five years. Marketing efforts, in overwhelming approval with 93 per- particular, are needed early in the cent rating the service “excellent.” process to assure that the public and A 1986 Federal Highway elected officials will understand the Administration study revealed that impacts of these traffic management incident management systems could efforts. Table 2.2 shows the different reduce congestion on approximately constituencies for incident manage- 30 percent of the major urban area ment and key “selling points” for freeway mileage, returning a each. Some metropolitan areas have benefit/cost ratio of approximately established “Congestion Management 4: 1, where benefits are measured as Teams,” with specific responsibilities the aggregate value of time saved by for planning, implementing, monitor- the motorists (Federal Highway ing and identifying these activities. Administration 1986). Other studies Of particular interest is the use of have produced the following benefit/ advanced technologies in the devel- cost ratios for specific types of actions: opment of incident detection and
Charlotte Motorist Assistance Patrol 7 6:l 1993 Chicago Emergency Traffic Control 171 1990 Denver Mile-High Courtesy Patrol 135.1 to 184.1 1993 Houston Motorist Assistance Patrol 19 1 1993 Houston Motorist Assistance Patrol 71to361 1991 Houston Freeway Courtesy Patrol 2.1 1973
SourceCambridge Systematics and The ATA Foundation 1996
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
Figure 2.3: Continued Options to Improve Response Time
Personnel Resource +++ $ Can save time in locating specially List trained personnel
Equipment and +++ $ Can save time in locating special Materials Resource equipment or personnel if list is List frequently updated
Peak Period Motor ++++ $$ to $$$ Roving motorcycle patrols can provide Cycle Patrols added surveillance on high iincident segments
Dedicated Freeway ++ to ++++ $$ to $$$$ Roving patrols can reduce response or Service Patrols time required by response vehicles
Personnel Training +++ $$ An emphasis on training through knowl Program edge and repetition can reduce response times
Tow Truck/ Removal ++ $ Provides faster access to equipment, but Crane Contracts may be problematic with competing firms
Improved Inter- +++ $ to $$ Adequate communication can help agency Radio to insure closest response vehicle IS Communications dispatched
Ordinances + $ Can provide additional travel lane for Governing Travel response vehicles on Shoulders
Emergency vehicle ++ $$ Requires iidentification of those freeway Access links which suffer from poor access
Alternative Route ++ $ If properly planned, can allow quicker Planning access
Equipment Storage ++ $ to $$ Provides faster access to equipment or Sites materials
Administrative + $ Provides forum to discuss and provide Traffic Management funding for area incident management Teams programs
Public Education +++ $ Can educate drivers regardrng disabled Program vehicle removal and help resolve incl- dents without need for actual response
Central Information +++ $$$ Provides a single location for monitoring Processing and incidents and allows coordination of Control response from many different agencies
Closely Spaced ++ $ Fast, accurate, easy location of incidents Milepost Markers Improves response speed
+ = Minor Benefits $ = Minor Costs ++ = Moderate Benefits $$ = Moderate Costs +++ = Substantial Benefits $$$ = Substantial Costs ++++ = Very Substantial Benefits $$$$ = Very Substantial Costs
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
Options for improving Motorist Information, Continued
Provides the most comprehensive infor- Route Guidance matron concerning traffi c situations, but IS still in development stage
A central location can collect data from multiple sources and provide a more accu- rate picture of existing traffi c conditions
Options for Reducing Clearance Time
Policy Requiring Fast vehicle Removal
Governing Shoulder
ion of those freeway
Alternative Rout e If implemente d wit h information systems, can serve to reduce congestron and Improv e mobilit y by rerouting uninvolve d vehicles
Identi fication of Fire ++ $ Can greatly speed clearance efforts by Hydrant Locations allowin g quick locating of utrlrtres in incidents with fire
Incident Response ++ to ++++ $ to $$$ Coordinated response teams should be Teams trained in a variety of equipment use
Incident Response +++ $ Once developed, should be Included in Manual regular training procedures for clear- ance efforts
Hazardous Materials +++ $ Once developed, should be included in Manual regular trainin g procedures for clear- ance efforts
Administrative Traffic + $ Provides a forum to discuss and provide Management Teams funding for area incident management + = Minor Benefits ++ = Moderate Benefits Public Educatron +++ $ Can educate drivers regarding disabled +++ = Substantial Benefits Program vehicle removal policies ++++ = Very Substantial Benefits
Total Station Survey- ++++ $ Can reduce time required for accident $ = Minor Costs ing Equipment investigation by nearly half $$ = Moderate Costs $$$ = Substantial Costs $$$$ = Very Substantial Costs
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM References Cambridge Systematics and The ATA Foundation. 1996. Incident Management, Report prepared for National Incident Management Coalition, Washington D.C., July. Collura, John et al. 1995. A Review and Assessment of the Massachusetts *SF Program, Final Report, University of Massachusetts, Department of Civil and Environmental Engineering, Amherst, MA, December. Connecticut Department of Transportation. 1990. Connecticut Freeway Traffic Management System, Final Report, Hartford, CT, August. Federal Highway Administration. 1986. Quantification of Urbun Freeway Congestion and Analysis of Remedial Measures, Report FHWA/RD-87/052, Washington, D.C.: FHWA, October. Institute of Transportation Engineers.1992. Traffic Engineering Handbook, Washington D.C.:ITE. J.Koehne, F. Mannering, and M. Hallenbeck. 1991. Framework for Developing Incident Management Systems, Washington Department of Transportation, Olympia, WA. Minnesota Department of Transportation. 1996. Traffic Management Program Overview, Twin Cities Metro Area, Metro Division, Freeway Operations Section, Report No. TMC 07043-0196, St. Paul, MN, February. Schrank, D. and T. Lomax. 1996. “Estimating the Effect of Operational Improvements in the Houston Area,” Transportation Research Record 1564, Transportation Research Board, Washington D.C. Skabardonis, A. et al. 1995. Freeway Service Patrol Evaluation, Institute of Transportation Studies Report UCB-ITS-PRR-95-5, University of California, Berkeley. Urban Land Institute. 199 1. 12 Tools for Improving Mobility and Managing Congestion, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Ramp Metering increased by 29 percent after ramp Description: Ramp metering is a metering was installed. When delays cost-effective technique for improv- on ramps are included, average speeds ing traffic flow on freeways. Using a still increased 20 percent and travel modified traffic signal placed at the times decreased 16.5 percent. An end of a ramp, ramp metering allows analysis of the FLOW system in traffic to enter the highway traffic Seattle (ramp metering and HOV either at pre-timed intervals or at lanes) revealed that in addition to times determined by traffic volume similar improvements in speed and travel time, highway volumes on the ramp or on the main highway. Ramp metering IS a cost-effective Although delays are often incurred by increased by about 60 percent as a technique for improving traffic ramp traffic, mainline capacities are result of ramp metering. An addi- protected and the overall operational tional benefit from ramp metering is flow on freeways. efficiency, usually measured in terms a decrease in the accident rate. of travel time or speed, is improved. Reductions from 5 to 50 percent have HOV bypass lanes on metered ramps been achieved through improved have been used to provide time sav- merging operations (Piotrowicz and ings for carpools, van pools, and Robinson 1995). The following is a buses. Minneapolis/St. Paul has 380 summary of ramp metering impacts ramp meters on the region’s freeways, from five locations in the United 350 of which are centrally controlled States: (Connecticut DOT 1990) Change in: by a traffic management center. In a new twist to the concept of ramp
metering, the Minnesota DOT is Portland, OR 16mph 41 mph -61% -43% NA metering 70 freeway-to-freeway ramps Minneapolis 34 mph 46 mph NA -27% +32% that have been severely congested . Seattle NA NA -48% -39% +62% over the past 10 years (Minnesota Denver 43 mph 50 mph -37% -5% +19% DOT 1995). Figure 2-4 shows the Long Island, NY 29 mph 35 mph -20% NA 0 basic concept of how ramp meters work. Various levels of entrance ramp control have been implemented Benefits/Costs: Ramp metering is across the country. Some are used primarily a tool for increasing traffic simply to improve the conditions at throughput on a freeway. However, specific problem merge areas. Two ramp metering also can be used to ramp metered locations in Detroit discourage drivers from using the resulted in increases on the freeway freeway for very short trips and to mainline of traffic volume and speed provide incentives for bus riders and (27 mph to 60 mph) at one location carpools by bypassing ramp conges- and increases of traffic volume and tion (often a one to four minute time speed (35 mph to 58 mph) at anoth- savings). A survey made for the er. A few states have focused atten- Federal Highway Administration of ’ tion on longer sections of routes in seven ramp metering systems in the urban areas and are now attempting United States and Canada revealed system-wide applications, notably in that average highway speeds California and Texas. Average speed
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
The common increase in freeway . Institute a proactive public speed and flow rate that results from relations program. ramp metering must be considered The implementation of ramp l Discuss with local governments a from the perspective of latent how the metering will be operated, metering system must include a demand. Over time, significant e.g., diversion strategies and how increases in freeway capacity will lead process where a variety of govern- to minimize impacts on local to large growth in traffic volume, pos- streets. ment and public groups are active- sibly encouraging travelers to switch ly involved in the conceptual plan- to auto use from transit services. . Perform ramp control experiments Therefore, ramp metering should be to demonstrate the effectiveness of ning and Implementation. implemented in conjunction with metering. corridor transportation demand man- . Install ramp meters in conjunction agement strategies that will encour- with freeway rehabilitation and age high-occupancy vehicle use. resurfacing. Implementation: A substantial . Provide updates on meter amount of time is needed to plan and operations at frequent intervals. implement a ramp metering system. Although ramp metering can The engineering aspects of ramp provide some important improve- metering are fairly wellknown. ments to the flow of freeway traffic, it However, ramp meters can often is not always an appropriate solution create significant controversy regard- for a number of reasons. Ramps ing the perceived inconvenience to motorists, and importantly the equity selected for this technique must be at locations where arterials feeding issue of providing improved freeway the ramps will not become severely traffic flow for those using the free- congested as a consequence of such way (e.g., suburban commuters) to action. Improvements to freeway the inconvenience of those trying to flows could be made at the expense of access it (e.g., center city residents). The implementation of a ramp transferring a more severe congestion problem to local streets. Possible metering system must therefore include a process where a variety of mitigation measures for such an occurrence include: government and public groups are actively involved in the conceptual . Increasing ramp storage, e.g., widen- planning and implementation. ing/increasing number of lanes.
The following implementation l Creating an areawide system strategy was recommended for incor- control of metering such that porating ramp meters into the backups are distributed among Hartford, CT freeway system many different ramps. (Connecticut DOT 1990). l Installing a queue detector at the . Involve all affected agencies and top of the ramp that will increase institutions in the process from the the metering rate to clear out the very beginning. vehicles in the queue.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM References Connecticut Department of Transportation. 1990. Connecticut Freeway Traffic Management System Final Report, Hartford, CT, August. Minnesota Department of Transportation. 1995. Overview of the MnDOT Ramp Metering Program, Report No. 07043-0795, Metro Division, St. Paul, MN, December. Piotrowicz, G. and J. Robinson. 1995. Ramp Metering Status in North America, 1995 Update, Report DOT-T-95-17, Federal Highway Administration, Washington D.C.
Highway Information Systems l Delays from non-recurring (See also Regional Multimodal Traveler . congestion Information Systems, Chapter 6) l Speed limits Description: Highway information systems represent an important ele- l Weather conditions ment of a freeway management sys- l Construction activities tem in that they provide the means of communicating to those traveling l Evacuation information on the road system. Such informa- l Implementation of new devices tion systems can consist of one or (e.g., ramp meters) Highway Information Systems more of the following: changeable More recently, the Internet has message signs, highway advisory can consist of the following: been used to provide real-time free- radio, and/or in-vehicle navigation . way condition information in a num- changeable message signs, and information systems. The intent ber of cities in the United States. of these information systems is to highway advisory radio, and/or Local cable TV channels could also provide dynamic information regard- provide real-time video of traffic con- in-vehicle navigation and ing existing traffic conditions so that ditions to the public as is being done information systems. travelers can make intelligent route : in Montgomery County, Maryland. choices if already on the road net- The state-of-the-art of this technolo- work, or even mode choice if the trip gy was demonstrated in the Atlanta has not yet started. Information that Traveler Information Showcase that could be conveyed includes: was put in place for the 1996 (Connecticut DOT 1990) Olympics (see Chapter 6 for a more l Delays due to recurring congestion detailed description of this program).
Benefits/Costs: The benefits of improved traveler information sys- tems include:
Early warning reduces the speeds of vehicles approaching a queue, resulting in fewer secondary acci- dents and associated delays. Decelerations have been found to be less severe in congestedloca- tions when advanced warn.ing was Invehicle Navigation System given.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY . Vehicles can divert to alternate services center. The majority of the routes when informed of an inci- vehicles were rented to Orlando dent that is blocking the road visitors. Figure 2-5 shows the results ahead. of improved information to drivers. Note in this figure that the reduction l Information on lane blockages in the different parameters were the induces lane changing away from result of tests with local drivers as that lane. well as out-of-town visitors. Motorist diversions will generally . Figure 2.5: Summary of TravTek In-Vehicle Information Demonstration contribute to overall savings in travel time over the delays likely to be experienced on the mainline. This Accidents assumes, of course, that there are Emissions alternative routes available to divert FUel to and that these routes themselves Wrong rums are not greatly congested. However, every effort should be made to keep Distance diverting motorists from using resi- Travel Time dential streets. 10 202530 35 Percent Reduction Highway information systems can . also be used at locations where heavy Source: FHWA 1996 congestion occurs. Highway advisory Implementation: A substantial radio, for example, is often used at amount of time is needed to plan and approaches to airport parking facili- implement a highway traveler infor- ties, near construction sites on free- mation system. Implementation ways, and in mobile units by incident requires the design and construction management teams. The transmitters of the system, using the steps required have a range of approximately 2 for a typical highway construction miles/3.2 kms in each direction. The project. However, the nature of this messages are changed remotely to system is such that experts in the reflect actual conditions. Other areas of electronics and information information dissemination tools can . systems must be involved in addition also be used including in-vehicle to highway and traffic engineers. displays (Federal Highway Admini- Local communication media should stration 1995). be included in the planning and pos- One of the more recent demon- sibly in the implementation stage. strations of in-vehicle traveler infor- Ideally, the system should be designed mation was the TravTek program in as an integral part of an areawide Orlando, Florida (Federal Highway freeway management program, as Administration 1996). This demon- described previously. An example of a stration consisted of 100 vehicles coordinated freeway corridor manage- equipped with in-vehicle information ment system that relies on traveler displays, a traffic management center information systems is shown in and a TravTek information and Figure 2-6. This approach has been
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
References Connecticut Department of Transportation (ConnDOT). 1990. Connecticut Freeway Traffic Management System, Final Report, Hartford, CT, August. Connecticut Department of Transportation (ConnD0T). 1995. ITS Needs Assessment and Service Assessment, Planning Report No. 1, Hartford, CT, November. Federal Highway Administration (FHWA). 1995. Responsive Multimodal Transportation Management Strategies and IVHS Report FHWA-RD-94-086, Washington D.C. Federal Highway Administration (FHWA). 1996. TravTek Evaluation Modeling Study, Report FHWA-RD-95-090, Washington D.C., March.
Freeway Corridor Traffic road operations to provide alternate Management (Including Arterial routes during emergencies, coordina- Surveillance and Control) tion of turning traffic signal phases, Description: Freeway corridor traffic and coordination of traffic signals at management consists of a coordinat- freeway interchanges with arterial ed application of the strategies dis- cross streets] (Institute of cussed earlier on both a freeway and Transportation Engineers 1992). The Important element of a on the adjacent arterials. The impor- Benefits/Costs: A good example of corridor traffic management tant element of a corridor traffic an operationally integrated freeway management strategy is that addition- strategy is that additional mobility and arterial road project is in New al mobility enhancements can occur York State. The Information for enhancements can occur by by combining the control and surveil- Motorists (INFORM) project was combining the control and lance of nearby arterial roads with conceived to optimize traffic flow adjoining freeway control and surveil- surveillance of nearby arterial through a 35 mile/56 km long and 5 lance activities. Motorists seeking to mile/8 km wide corridor of freeways roads with adjoining freeway avoid the congested freeway could and arterials in Long Island by inte- use parallel arterial routes or other control and surveillance activities grating ramp metering, coordinated freeways, which in turn increases traffic signal control, and variable congestion on these facilities. Traffic message signing into one comprehen- waiting to enter the congested free- sive system sharing the same software way may spill onto adjacent surface and database. INFORM consists of streets, further aggravating conges- the following elements: (Domjan and tion. An integrated freeway and arte- Han 1994) rial network surveillance system con- sists of incident surveillance and . 2069 roadway embedded vehicle management, entrance ramp control, sensors exit ramp control, freeway mainline . 101 variable message signs control [which includes driver infor- l mation systems, variable-speed con- 75 ramp meters trol, mainline metering, lane control, l 34 closed circuit TVs and reversible lane control], and cor- 22 Citizen Band radio receivers ridor control [which includes coordi- . nation of traffic signals on frontage l central control center roads and on parallel arterials, coordi- . 133 centrally controlled signalized nation of ramp control and frontage intersections
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM Both California and Texas have Lomas 1991).A recent case study embarked on similar ventures. An of TRANSCOM a regional institu- integrated corridor concept is found tional structure for coordinating a on the Santa Monica freeway corri- large number of transportation and dor in Los Angeles, 12 miles/l9 kms enforcement agencies in the New long and 5 miles/8 kms wide with five York City area, illustrates the benefits arterial alternative routes. A com- of such an approach (Wilson 1996). mon database has been developed for A consortium of 15 transportation roadway management and motorist and traffic enforcement agencies cre- information. Personal computer and ated TRAN’SCOM, an incident telephone information access and in- management and communications vehicle navigation information are clearinghouse. TRANSCOM part of the state-of-the-art activities. receives updated information on One of the few studies that have esti- roadway emergency situations, special mated the benefits of freeway man- events, and any other incidents that agement focused on the existing and require immediate attention. projected (in the year 2000) freeway TRANSCOM staff evaluate this traffic management (FTM) systems in information and transmit it to all Houston. This study estimated that member agencies via encoded pagers, the 48-mile/77-kilometer FTM sys- giving them real-time information on tem in 1995 reduced daily recurrent events affecting traffic conditions. delay by 6,300 vehicle-hours which is This ensures quick response. One of the equivalent of an additional 56 the important activities of this effort freeway lane-miles. For the projected is the transmission of digitized pic- 110 mile/l 77-km FTM system in tures of incident scenes by cellular 2000, the reduction in daily recurrent telephone to a personal computer at delay would be 21,100 vehicle-hours the TRANSCOM center. To mini- which is the equivalent of an addi- mize disruptions and improve the effi- tional 153 freeway lane-miles ciency of the highway system, (Schrank and Lomax 1996). TRANSCOM has developed a regional database of all scheduled The most important benefits associated with these types of projects is the reduction construction and maintenance pro- jections, and has prepared pre- in delay that occurs with improved traffic flow in the corridor. arranged diversionary plans for the The most important benefits asso- major highways in the region ciated with these types of projects is (Federal Highway Administration the reduction in delay that occurs 1987). Some benefits associated with with improved traffic flow in the TRANSCOM include daily coordi- corridor. A sophisticated surveillance nation among the operating agencies and control program in a corridor in a major metropolitan area, longer could increase average vehicle term coordination of construction throughput by 12 to 20 percent and scheduling on the regional highway produce benefit/cost ratios of between network, and sharing of new trans- 10 and 12 to 1 (Henk,) Poe, and
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY portation management technologies. . Even if the coalition has a uniform For example, TRANSMIT, the set of goals and objectives, the TRANSCOM System for Managing motivations among the member Incidents and Traffic, uses vehicles agencies for participating or not equipped with transponders for elec- participating in the coalition can tronic toll collection as probes to be highly variable. monitor traffic. Although the origi- Even if the executive management nal purpose of this project was to . of a constituent agency supports a monitor for incidents, implementing regional coalition, this may not agencies have found great use with necessarily translate into support the collected data for determining for regionalism at all levels and all travel times between key points sectors of the agency. which has been used for scheduling staffing levels at toll plazas. . While uniform procedures among the member agencies may be desir- Of some importance to regional able in making a coalition effec- transportation, the TRANSCOM tive, that is an unlikely situation The barrier to further efforts in program was one of the major for a coalition that has no authori- foundations for a much larger effort integrated corridor solutions is ty over its members. called the I-95 Coalition which has largely institutional and financial. expanded TRANSCOM’s impact l There should be no inconsistency Only by working side by side, as from Maine to Virginia (see Chapter between the self-interest of each 6 for a more detailed description of agency and the collective, regional part of the whole solution, can the I-95 Coalition). interest of the coalition. regional improvements result. Implementation: Integrated corridor . Coalitions should focus on things solutions are in the early stages of that truly are better done collec- implementation in several cities. ITS tively. technologies are being used as the l To develop from an abstract ideal foundation of many of these efforts. into a going concern, a coalition The barrier to further efforts (large or has to provide a valuable service- small, simple or sophisticated) is it has to help its constituent agen- largely institutional and financial. cies do their business and serve Only by working side by side, as part their customers more effectively. of the whole solution, can regional Another example of integrated improvements result. The freeway/arterial systems is the con- TRANSCOM example above illus- cept of Traffic Management Teams in trates this point quite well. As noted Texas. There are currently 12 teams in (Wilson 1996), there are several operating in the state, covering the general principles that are inherent seven largest metropolitan areas and in regional cooperative efforts: the nine largest cities as well as other . Lack of authority should not deter smaller areas. Each team brings a coalition from pursuing its mis- together professionals from various sion with confidence. traffic-related agencies in the area, and works cooperatively to solve the
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM trafficproblems.The rapid Integrated freeway and arterial spread of the team concept and their network surveillance/control pro- wide acceptance among the larger grams are important tools for better cities in Texas is evidence that effec- managing the existing road system. tive interagency communications can These programs should be integrated often lead to cooperation. The Texas with multimodal traveler information Department of Transportation has systems so that corridor transporta- also sponsored an aggressive educa- tion improvements benefit not only tion program for both highway/traffic auto users, but all travelers. As noted professionals and the general public. in Chapter 1, the management of The viability of coordinated traffic transportation supply should be inte- management schemes is demonstrat- grated with transportation demand ed through workshops, seminars, and management and land use policies. training courses. .
References Domjan, R. and B. Han. 1994. “INFORM-An Updated Performance Evaluation From 1990 to 1994,” ITE Compendium of Technical Papers, Washington, D.C. Federal Highway Administration. 1987. Urban Traffic Congestion - A Perspective to the Year 2020, San Francisco, CA, Region 9 Office of FHWA, September. Henk, R., C. Poe, and T. Lomax. 1991. An Assessment of Strategies for Alleviating Urban Congestion, Texas Transportation Institute, Report 1252-lF, Texas A&M University, College Station, TX, November. Institute of Transportation Engineers. 1992. Traffic Engineering Handbook, Washington D.C. Schrank D. and T. Lomax. 1996. “Estimating the Effect of Operational Improvements in the Houston Area,” Transportation Research Record 1564, Transportation Research Board, Washington D.C. Wilson, F. 1996. “The TRANSCOM Coalition: Multi-Jurisdictional Issues in ITS,” ITS Quarterly, Spring.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Providing Additional Lanes Without along a comparable modified Widening the Freeway section. Description: Using freeway shoul- Accident rates at modified freeway ders as travel lanes has occurred in . sections are somewhat higher than some cities since the late 1960s, with rates for unmodified sections. many of these lanes being devoted to HOV use. These modifications . Truck accident rates are almost include, 1) using one or more shoul- always higher on modified sections. ders as travel lanes (this is often done Another study examined the only during peak hours and in the northern Virginia I-95 use of shoulder peak direction), and 2) reducing lane lanes for the entire day (Chen 1995). widths to provide additional lanes This 8-mile/1 2.9~km section of within the existing pavement. Interstate has a left lane designated Benefits/Costs: Significant increases for 3+ HOV vehicles, two general in capacity (up to as much as 30 per- purpose lanes, and a right shoulder cent and more) are possible. These lane which is used as a conventional capacity increases, however, have travel lane. This study concluded: often been achieved with some . The use of shoulder lanes Modifications to provide additional increase in accident rates. Thus, the increased freeway capacity signifi- lanes without widening the design of such lanes must clearly take cantly. Analysis indicated that freeway include: into consideration the safety aspects removing the shoulder lanes from I) using one or more shoulders as of the particular freeway section. general purpose use would increase travel lanes; Even though such treatments should queue lengths by 140 percent and be considered temporary, an FHWA system delays by 929 percent. The 2) reducing lane widths to provide additional lanes within the existing staff study found that in cities with HOV and shoulder lanes carried pavement. populations over one million, almost 47 percent of total vehicles and 63 32 percent of the urban freeway percent of total travelers on the mileage could experience reduced freeway. congestion through such low-cost No adverse impacts on general measures (Federal Highway Admini- . traffic accident frequency was stration 1987). found. Fatality rates were lower A recent study of freeway shoulder than the “before” situation. lanes found: (Curren 1995) Importantly, in keeping with the l Freeway capacity in excess of 2,200 concern mentioned earlier about safe- passenger car per hour per lane ty, several modifications were made were observed at these sites. in the corridor to maintain opera- . Modified sites have a greater tend- tional and enforcement activities. ency to fall into more congested In particular, emergency pullouts conditions at high volumes than were built and signed to allow for safe unmodified sites. storage of disabled vehicles. . The range of observed speeds Costs will normally vary depend- along an unmodified freeway sec- ing on the individual circumstances tion will be somewhat greater than and the condition of the existing
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM freeway, but in general, costs per mile there are no other less-than-standard will be $1.5 million for construction features; however combined with and engineering, and $12,000 per shoulder width reductions, substan- year for maintenance. Overall, low- dard sight distance, and other fea- cost improvements have the potential tures, (these) lanes may not provide of returning a benefit/cost ratio of up the same operation.” to 7:1 This means that when shoulder The primary advantages and disad- use is being considered for traffic flow, antages in implementing this tool are: careful planning and design should
Left shoulder not used as much for Usually requires restriping When shoulder use is being Use of Left Shoulder emergency stop or emergency sight distance problem with some enforcement considered for traffic flow careful median treatments Least expensive if width IS available planning and design should occur Trucks often restricted from left lane to avoid any potential safety Use of Right Shoulder Often the easiest to Implement Right shoulder IS preferred area for problems. emergency stops and enforcement Sight distance changes at merge and diverge areas of ramps
Use of Both Shoulders Not recommended Requires restriping Use ONLY in extreme cases Safety concerns Enforcement difficult Incident response longer Manintenance more difficult and expensive
ource current 1995
mplementation: Whenever occur to avoid any potential safety mprovements are made to a highway problems. In addition, structural he level of safety should be capacity of a highway varies across mproved. As noted in (AASHTO the cross section. The shoulder is not 997): . often constructed to accommodate traffic loads. Pavement failure and “The need to accommodate more subsequent repair under traffic condi- traffic within existing or limited addi- tions will have an effect on both tional right-of-way on high volume capacity and safety. Changes in traffic urban freeways has led some agencies and operational patterns often have to increase capacity by exchanging an impact that goes beyond the full-lane or shoulder widths for addi- immediate facility that is being affect- tional travel lanes with reduced ed. Thus, additional capacity provid- widths. Any proposed use of less- ed in one corridor could very well than-full-atandard cross-sections must influence demand on adjacent arteri- be analyzed carefully on a case-by- als or on nearby freeways. Such case basis. Experience indicates that issues must be considered in the 12ft/3.3m lanes can operate safely if
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY analysis that precedes a decision to l Comprehensive incident detection use shoulder lanes. and response systems should be considered for sections with sub- The state transportation agency standard lane and shoulder widths. would most likely plan and design these improvements as a typical high- . If both shoulders are removed, way project, and enter into a con- mitigating measures should struction or lane striping contract in include: adequate advisory and the usual manner. Cooperation and regulatory signing, constructing coordination between the state high- frequent emergency pullouts, way agency and the traffic enforce- active overhead and side-mounted ment officials responsible for enforce- changeable message signs and sig- ment (e.g., the state police) is essen- nals, continuous lighting, truck tial. Because the use of breakdown lane-use restrictions, dedicated ser- lanes is not consistent with federal vice patrols, and continuous design criteria, federal approval will enforcement. be required if the highway facility is l For sections greater than 1.5 kms on the federal-aid system. where inadequate shoulders are pro- When this action is being consid- vided, emergency pullouts should ered, it typically generates opposition be considered where feasible. from traffic enforcement agencies and motorists who are mainly concerned The state transportation agency would most likely plan and design the improvements about safety (i.e., the emergency lane as a typical highway project, and enter into a construction or lane striping contract is used for traffic flow rather than by emergency vehicles or breakdowns). in the usual manner: Cooperation and coordination between the state highway Also, there is concern that the flow agency and the traffic enforcement officials responsible for enforcement is essential. from entrance ramps will be adversely affected. These are all legitimate Given that the major reason for concerns which should be addressed. implementing this action is to The response to these concerns increase the vehicle-carrying capacity include the following (AASHTO of a freeway, the planning for this 1997): action should consider the likely impact of induced traffic demand that l Where shoulders are converted to will now be generated on air quality, travel lanes, removing the left-side environmental issues, and eventually shoulder is preferable. on the long-term operation of the . Where a highway with a narrow freeway. median and median barrier is A complete guide for the imple- being considered for using the mentation of this tool is found in median shoulder for a travel lane, (Current 1995). curves should be checked for ade- quate stopping sight distance.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM References American Association of State Highway and Transportation Officials (AASHTO), 1997. Highwuy Safety Design and Operations Guide, Washington D.C. Chen, C. 1995. “Evaluation of HOV and Shoulder Lane Travel Strategy for I-95”, ITE Journal Institute of Transportation Engineers, Washington D.C., September. CurrenJ.E. 1995. Use of shoulders and Narrow Lanes to Increase Freeway Capacity, NCHRP Report 369, Transportation Research Board, Washington, DC. Federal Highway Administration (FHWA). 1987. Urban and Suburban Highway Congestion, Working Paper No. 10, Washington, D.C., December.
High Occupancy Vehicle (HOV) travel time reliability for HOV lane Facilities users which can be a strong induce- HOV lanes bypass serious conges- Description: An increasingly popular ment to use transit or ridesharing. In method for increasing the person-car- addition, HOV facilities allow transit tion points thus decreasing travel rying capacity of a freeway is to desig- operators to provide a more reliable times and increasing travel time nate some portion of the roadway for transit service given that buses are reliability for HOV lane users which use solely by those using high occu- not now subject to the unpredictable pancy vehicles (HOVs). HOVs are conditions of freeway operation. can be a strong Inducement to use usually defined as including buses, Several types of HOV facilities are transit or ridesharing vanpools, and carpools. HOV lanes found in the United States, includ- bypass serious congestion points thus ing: (see Figure 2-8) decreasing travel times and increasing Exclusive HOV Facility, Separate Figure 2.8: Freeway HOV Lane Applications Right-Of-Way. A roadway or lane(s) developed in a separate right-of-way
Reversible-Flow and designated for the exclusive use of high occupancy vehicles (usually defined as vehicles carrying at least two or three persons per vehicle).
Two-Way (Concurrent Flow) Exclusive HOV Facility, Freeway Right-Of-Way. Roadways or lanes built withii the freeway right-of-way that are physically separated from other freeway lanes and are designed for the exclusive use of high occupancy vehicles for some portion of the day.
Borrowed for HOVs Concurrent Flow Lane. A freeway lane in the peak direction of travel Queue Bypass (commonly the inside lane), not physically separated from the other general traffic lanes, and designated for the exclusive use by high occu- pancy vehicles during some portion of the day.
Source. Texas Transportation Institute 1992
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Contraflow Lane. A freeway lane (commonly the inside lane) located (Who Previously Drove Alone ) in the off-peak direction of travel designated for exclusive use by high l-l 0, Katy Freeway, Houston 36% 36% l-394, Twin Cities 43% occupancy vehicles (usually buses l-395, Northern Vlrgmia 23% only or buses and Vanpools) traveling l-45, Houston 39% I-10, San Bernadmo Freeway, 46% in the peak direction during some Los Angeles portion of the day. The lane is typically separated from the off-peak To the extent that HOV lanes can direction travel lanes by plastic posts, reduce the number of single occupant pylons, or movable concrete barriers. vehicles on the road, air quality bene- Benefits/Costs: The primary purpose fits will occur. Some estimates of air of HOV facilities is to increase the quality benefits include a 21 percent people-moving (versus vehicle-mov- reduction in pollutant emissions in ing) capacity of a freeway. As shown the I-395 corridor in Washington in Figure 2-9, the results can be quite D.C.; and a 10 to 20 percent reduc- dramatic. The peak direction, person tion in emissions during the peak volumes per lane are substantially hour on the San Bernadino Freeway higher than comparable non-HOV in Los Angeles. The major reason for using an freeway lanes. The same can be said Improvements in transit operations for average auto occupancy, the num- HOV lane often cited in surveys have also been shown to be signifi- ber of 2+ Carpools, and the number of cant. In Houston, the peak hour bus of HOV lane users is improved bus passengers (Henk, Morris and operating speeds on the four major Christensen 1994). The I-64 HOV travel time. freeways with HOV lanes have lane in Hampton Roads, Virginia is almost doubled from 26 mph to 54 typical of what one sees with the mph, reducing the revenue bus-hours implementation of an HOV lane. needed to provide service by 31,000 The freeway showed an increase of hours and saving the transit authority almost 3,000 persons carried with a approximately $4.8 million annually corresponding decrease of 7 11 vehi- (Henk, Morris, Christensen 1994). cles after the lane was opened in In Pittsburgh, the East Busway has 1992. reduced bus travel times by 40 to 50 The major reason for using an percent. In Ottawa, Ontario, where a HOV lane often cited in surveys of HOV lane users is improved travel time. Figure 2-10 shows the amount of time saved for different HOV facil- ities in the United States. These travel time savings have been an important factor in attracting drivers to ridesharing and transit. For exam- ple, the following percentage of HOV lane users previously drove alone:
Contraflow Lanes for High Occupancy Vehicles
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
. Two HOV facilities in Hartford, Implementation: A recent survey of Connecticut have provided a five- transportation professionals identified minute time savings to express bus the following concerns in implement- users. When a minimum vehicle ing HOV facilities (Tumbull and occupancy requirement was Capelle 1996). changed from 3+ to 2+ in 1993, Enforcement problems/lack of lane use increased from 3 15 to 9 13 . enforcement vehicles. l Converting general purpose lanes HOV facilities have been planned, to HOV lanes designed and constructed in a three to eight-year time frame. The con- .2+ vs. 3+ occupancy require- struction involves well-known high- ments/managing demand
One of the important decisions way technology. HOV lanes can be l Concern over low utilization levels opened as each section is completed l Funding that must be made early in the thus providing immediate benefits as
HOV lane planning process IS the the entire facility is being finished. l Opposition to HOV facilities/lack The costs of an HOV facility will of political and public acceptance minimum occupancy requirements vary depending upon the type of l Safety issues for those vehicles allowed in the facility. HOV facilities constructed l Marketing lane. The selection must allow on separate rights-of-way can cost from $7 to $8 million per lane-mile; As indicated, one of the important for growth as more commuters barrier-separated facilities constructed decisions that must be made early in choose to switch to ridesharing in freeway rights-of-way cost from $4 the HOV lane planning process is the to $6 million per lane-mile; concur- arrangements to take advantage minimum occupancy requirements rent flow facilities cost from $1 to $2 for those vehicles allowed in the lane. of the time savings afforded by million per lane-mile; and contraflow The selection must allow for growth the lane. lanes cost $0.5 to $1 million per lane- be more commuters choose to switch mile (Henk, Poe, and Lomax 1991). to ridesharing arrangements to take The annual operations and enforce- advantage of the time savings afford- ment cost will also vary depending on ed by the lane. In recent years, a the level of enforcement provided. A minimum of two persons per vehicle study of the Houston HOV lanes, for has been the most common occupan- example, indicated that the annual cy requirement, although a 3+ operating/enforcement cost per HOV requirement has also been used. lane was between $250,000 and Allowing too small of a minimum $300,000. occupancy can create excess demand Evaluation of HOV priority lanes for the facility, thereby negating any has shown that the benefit/cost ratios time savings and incentives. Figure for such projects are frequently in 2-11 shows the results of lowering the excess of 6 to 1. Thus, HOV lanes occupancy rate from 3+ to 2+ on the should be considered a very cost Katy Freeway in Houston and the effective tool in a region’s mobility consequences on the number of vehi- enhancement program. using the lane. In addition to the increase in number of vehicles
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY
A major innovation in the physi- One of the most comprehensive cal operation of HOV lanes has HOV strategies at the metropolitan occurred over the last 10 years with level is found in Minneapolis/St. the development of movable barriers. Paul. HOV lanes are currently on These barriers (which are attached I-394 and I-35W, with some 55 HOV together) are stored at the side of the ramp meter bypasses in operation freeway during off-peak periods and throughout the metropolitan area. then put in place with a large tractor- Three parking garages in downtown type machine that lifts the barriers Minneapolis with direct access to and places them in predetermined I-394 have been constructed with locations while the machine travels preference given to HOV users. down the freeway. This approach is Remote park-and-ride lots have been used primarily to create (on a daily constructed and timed transit transfer basis) a contra flow HOV lane that is stations to encourage transit rider- physically separated from on-coming ship. The metropolitan area has also traffic. Such systems are found in created a “Team Transit” which Boston on I-93 and in Washington identifies low cost enhancements to D.C. on I-66. They have also been HOV users (Minnesota DOT 1996). used at locations where limited This is the type of comprehensive capacity causes bottlenecks such as HOV program that is necessary to bridges. produce significant results. The ITE Traffic Engineering Most state transportation agencies having responsibilty for freeways In metropolitan Handbook provides guidelines for the areas have design guides which strongly influence the process and ultimate design feasibility of different HOV applica- tions on freeways (Institute of of an HOV lane. Transportation Engineers 1992).
There are a number of HOV pref- For Separate HOV Facilities: The erential treatments that may be effec- potential for HOV lanes on con- tive in promoting HOV use when trolled access facilities is limited to implemented as elements of a region- high-volume urban corridors. al HOV strategy. The following feae Because of the severe right-of-way tures are very important in planning and construction cost constraints for a successful HOV facility: associated with such corridors, . park and ride lots consideration of sole-traveled-way . metered ramp by-pass HOVs should take place in the . preferential parking and pricing planning stage. l signal priority l Projected corridor demand during l exclusive access ramps peak periods should indicate l turning restrictions potentially serious capacity l preferential tolls problems. A heavy peak period l toll preferential lanes directional split of 65-35 percent l transit passes or 70-30 percent would be typical of such a corridor.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY l The corridor should be of suffi- . Contra-flow priority lanes should cient length and should carry a be considered only when a consid- high enough volume of traffic to erable flow imbalance prevails provide the potential for large time during peak traffic periods and if savings to users of the HOV facili- the remaining off-peak direction ty. A minimum of 10 minutes traffic can flow at an acceptable time savings is considered signifi- level of service. cant, with a 15 to 20 minute For safety reasons, contra-flow potential time savings considered . operations must be at all times desirable. clearly and unmistakably identified . Transit bus demand should exist in by opposing traffic. the corridor. . Concurrent-flow HOV lanes l HOV lanes on sole-traveled ways should be physically separated The ITE Traffic Engineering should normally be designed with from the normal lanes by a buffer Handbook provides guidelines for a minimum of two lanes. zone that will safely ensure the desired separation. the feasibility of different HOV l Lane use vehicle occupancy requirements should be carefully l Exclusive connections or bypass applications on freeways. considered if an acceptable level ramps should be considered where of service is to be provided for all time savings to the HOV users are users. greater than the costs when the ramp and through-lane capacities Access to the separate HOV lanes . are not adversely affected. should preferably be restricted to special access ramps from grade- One of the key issues associated separated roadways. with contra-flow or concurrent flow lanes is taking existing highway In planning and design, maximum . capacity from general purpose use operation flexibility should be pre- versus widening the road or restriping served that will allow changes to the highway lanes to provide addi- the operation of the HOV facility tional HOV capacity. Beginning in should it become unworkable in the mid-1970s with a controversial practice. “take-a-lane” project on the Santa For Concurrent or Contra-Flow HOV Monica Freeway in Los Angeles, Lanes: HOV lanes that substantially reduce . The lane should be physically sep the vehicle-carrying capacity of the arated from the remaining freeway freeway have faced strong opposition lanes. from those who argue that such use and impact is unwarranted. For those l Physical modifications to the free- projects where a “take-a-lane” design way that reduce lane widths must is the only feasible alternative or be approached with extreme cau- where public policy is designed to tion. Minimum shoulder widths should be maintained.
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM restrict automobile use, project imple- thelanefora price,theso-called high mentation should include a compre- occupancy toll lane or “HOT” lane. hensive marketing campaign to influ- Some ITS demonstration projects are ence public attitudes toward the doing just this (see Chapter 6). HOV lane. In addition, such an A comprehensive discussion on HOV lane might best be implement- the design of HOV lanes is found in ed during a freeway reconstruction (AASHTO 1992). project, or serious consideration be given to allowing non-HOV use of
References AmericanAssociation of State Highway and Transportation Officials (AASHTO). 1992 Guide for the Design of High Occupancy Vehicle Facilities, Washington D.C. California Department of Transportation. 1991. High Occupancy Vehicle Guidelines for Planning, Design and Operations, Sacramento, CA, July. Henk, R., D. Morris, and D. Christensen. 1994. An Evaluation ofHigh-Occupancy Vehicle Lanes in Texas, 1993, Research Report 1353-1, Texas Transportation Institute, Texas A&M University, College Station, TX, October. Henk, R., C.Poe, and T. Lomax. 1991. An Assessment of Strategies for Alleviating Urban Congestion, Research Report 1252.lF, Texas Transportation Institute, Texas A&M University, College Station, TX, November. Institute of Transportation Engineers. 1992. Traffic Engineering Handbook, ITE. Minnesota Department of Transportation. 1996. Traffic Management Program Overview, Twin Cities Metro Area, Report TMC 07043-0196, St. Paul, MN. Texas Transportation Institute. 1992. High Occupancy Vehicle Project Case Studies: Historical Trends and Project expericences Technical Report 925-4, Texas A&M University, College Station, TX, August. Transportation Research Board. 1995. HOV Systems in a New Light, Proceedings of a National Conference on High-Occupancy Vehicle Systems, June 5-8, 1994, Los Angeles, CA, Transportation Research Circular 442, July. Tumbull,K.and D.Capelle. 1996. Development of an HOV Systems Manual, Interim Report, National Cooperative Highway Research Program, March. Vuchic, V., et al. 1994. The Bus Transit System: Its Potential Implementation and Obstacles, Report # DOT-T-94-20, Federal Transit Administration, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Park-and-Ride Facilities activity, so-called “shared-use” facili- Description: The primary purpose of ties. Portions of shopping center, park-and-ride facilities is to provide a church, or school parking lots can be common location for individuals to devoted to park-and-ride users by transfer from a low- to high-occupan- negotiating agreements with the own- The primary purpose of park-and cy travel mode. In the context of ers of these lots. In addition, park- ride facilities IS to provide a freeway corridor management, such and-ride facilities should facilitate common location for individuals facilities become an important com- access to HOV use for non-motorized ponent of efforts to encourage HOV modes of transportation (e.g., bicycle to transfer from a low- to high- and walking) where such access use. There are three major types of occupancy travel mode. park-and-ride facilities: (AASHTO modes are likely to be used. 1992) Benefits/Costs: The benefits of park- Remote Park-and-Ride: Facilities and-ride facilities relate to user cost that provide a change-of-mode ser- and travel time savings, more effec- vice from a suburban or satellite com- tive congestion management, lower munity to another suburb, a major demand for parking spaces in con- employment site, central business dis- gested areas, reduced energy con- trict (CBD), or major activity center sumption and vehicular emissions, via an established parking facility enhanced mobility, and improved with express transit service to the efficiency of the transit system destination. (Tumbulll995). In almost all cases, the benefits of park-and-ride facilities Local Service Park-and-Ride: are tied to those related to transit use Facilities located along a local bus (described in Chapter 4). A 1986 route that is served by nonexpress, study of 305 park-and-ride lots found local transit operations. Demand for that the previous mode of work travel these facilities is much smaller than for those now using park-and-ride lots that for remote lots. in conjunction with some form of Peripheral Park-and-Ride: Located HOV use ranged from 11 to 65 per- at the edge of the CBD, these cent who drove alone (with an aver- facilities are intended to intercept age across all lots of 49 percent); from automobiles before they enter 5 to 28 percent (with an average of congested city streets or downtown 23 percent) who carpooled; from 5 areas. The feasibility of these lots to 49 percent (with an average of 10 depends greatly on the pricing and percent) who used transit; and from 0 limited availability of parking in the to 29 percent (with an average of 15 downtown area. percent) who did not previously make the trip (Bowler et al 1986). Users of park-and-ride facilities are Encouraging the use of nonmotorized very sensitive to the time costs of modes for accessing the park-and-ride making a transfer, and thus facility lot would further augment the con- design must be convenient, easily gestion relief and mobility enhance- used and safe. Park-and-ride facilities ment benefits of these facilities can be built exclusively for such use, (Replogle and Parcells 1992). or they can be part of some other
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM Perhaps the only benefit of formal l Locate park-and-ride facilities in park-and-ride facilities that is not advance of areas experiencing related directly to the use of alterna- major traffic congestion which tive modes is the experience in many would provide a more convenient urban areas of ad hoc parking occur- and comfortable modal transfer. ring on highway shoulders or at other Locate park-and-ride facilities in nearby locations. Such “informal” . areas with high levels of travel parking can create a hazardous traffic demand to a major activity center situation. Developing park-and-ride or centers served by the facility. facilities can thus provide safety ben- efits at these locations. l Include preferential transit ser- vices, either rail or HOV lanes, to The costs of providing park-and- enhance park-and-ride facility ride facilities will vary significantly by usage. the type of facility. Shared ride facili- ties where no additional major capital l Locate park-and-ride facilities so investment is necessary could be put that commuters do not have to in place simply through highway backtrack to reach the lot. signing and pavement marking, with . Orient park-and-ride facilities to a fee or liability insurance paid by the ensure good accessibility and visi- lot operator. Larger scale lots often bility to increase awareness of the lots. Users of park-and-ride facilities are very sensitive to the time costs of making a trans- l Locate park-and-ride facilities at fer, and thus facility design must be convenient, easily used and safe. appropriate distances from one another so that the market service built in conjunction with the con- areas do not overlap. struction of new interchanges or tran- sit lines could cost significantly more, l Consider partnerships to include with the most expensive lots being private services at or near park- those that provide parking structures and-ride lots. adjacent to major transit lines. Costs .Encourage cooperation among can range from $400,000 to $4.$5 agencies in developing, operating, million depending on the circum- serving, and enforcing park-and- stances. ride facilities. Implementation: The most impor- This latter point is critical. tant considerations in locating park- Although there are many successful and-ride facilities include: (Tumbull park-and-ride lots in the United 1995) States that only provide the ability to l Locate park-and-ride facilities in transfer from an automobile to car- congested travel corridors where pools or vanpools, the most successful modal transfer clearly will be per- lots provide some form of direct ceived by users as having substan- access to high-speed transit services. tial time savings. In addition, a police presence is important in promoting a safe and
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY secure environment for leaving a car. keep shoppers out of transit spaces, Planning park-and-ride facilities must how to handle excess transit parkers therefore include the participation of who overflow into shopping center a large number of agencies and parking spaces, and the reduction in groups; at a minimum, state and local parking requirements for the shop- transportation agencies, transit ping center if spaces are leased for providers, enforcement agencies, transit purposes. local governments, citizens, and the Intelligent transportation systems media. (ITS) technologies can play an In those cases where existing park- important role in the operation of ing lots are going to be leased for park-and-ride facilities. ITS technolo- park-and-ride use, agreements must gies could provide pre-trip and be developed that cover such things enroute real-time information to as: what types of improvements will commuters on the conditions being be made and by whom? who will per- faced in the travel corridor and at form maintenance? what types of lia- park-and-ride facilities. In-vehicle bility insurance are necessary and navigational aids could guide travel- who will provide it? who will be ers to parking lots. In addition, travel allowed to use the site?, and other kiosks at these facilities could provide legal issues relating to public use of information on available travel private property- In addition, lease options or on the schedule/likely arrangements often deal with how arrival of the next bus/train. the spaces will be delineated, how to ......
References American Association of State Highway and Transportation officials (AASHTO). 1992. Guide for the Design of Park-and-Ride Facilities, Washington DC. Bowler, C., et al. 1986. Park-and-Ride Facilities, Guidelines for Planning, Design and Operation, Federal Highway Administration, Washington D.C., January. Replogle, M. and H. Parcells. 1992. Case Study No. 9, Linking Bicycle/Pedestrian Facilities with Transit, FHWA Report FHWA-PD-93-012, Washington D.C., October. Trunbull, K. 1995. Effective Use of Park-and-Ride Facilities, NCHRP Synthesis 213, Transportation Research Board, Washington D.C.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM PricingStrategies Implementation: The reader is Description: A pricing strategy for a referred to chapter five for further region’s road system would include description. charging a premium to motorists who All of the tools described so far wish to drive during peak travel peri- have been discussed in light of their ods by using tolls, fees for congested application to freeways (except in the areas, or surcharges to parking prices. section on freeway corridor traffic The travel impact of such pricing management). The following sections schemes could vary widely. Travelers focus on those tools that are primarily A pricing strategy for a region’s could change routes to untolled applied to urban arterials road system would Include charg- roads, change time-of-day of travel to ARTERIALS AND LOCAL avoid tolls, switch transportation ing a premium to motorist who STREETS: DESIGN modes, change destinations for those wish to drive during peak travel trip purposes where such is possible, In 1993, approximately 41 percent of all annual vehicle miles of travel in periods by using tolls, fees for combine more errands on one trip (so-called trip chaining), telecom- the United States were on urban congested areas, or surcharges to mute, and in the long run even arterials (non-freeway) and local parking prices reduce the number of autos owned. streets. Improving travel flow on One of the major advances in road these roads could thus be an effective pricing is the advent of electronic toll means of improving urban mobility. collection (ETC) systems. Tags or For example, there are approximately smart cards located in a vehicle are 240,000 traffic signals in the United “read” electronically as it passes a States of which about 54 percent sensor at a tollgate. A computer (130,000) are interconnected in traf- deducts the amount of toll from the fic signal systems (Henk, Poe, and driver’s prepaid tag or is billed Lomax 1991). These signalized inter- monthly. Studies have indicated that sections, together with other ETC can increase conventional toll improvements on the arterial street plaza lane capacity by 50 to 150 per- system, provide significant opportuni- cent while permitting free-flow ties for increasing capacity and mak- speeds of up to 55 miles per hour. ing better use of existing arterials Some issues associated with ETC without major new construction. implementation include using pre- The following sections briefly payment versus post-payment pur- describe the available procedures that chasing schemes, privacy issues asso- should be considered from the per- ciated with the use of ETC collected spective of roadway design. data, costs and legislative require- ments for some types of enforcement Super Street Arterials (e.g., photos of license plates), and Description: Super street arterials are the overall enforcement strategy of wide, multi-laned arterials with limit- ETC-equipped lanes. ed access provided from intersecting streets. To the degree possible, major Benefits/Costs: Pricing strategies are intersecting streets are grade-separat- discussed in great detail in ed in order to minimize the need for Chapter 5-Managing Transportation Demand. A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY traffic signals. Super streets take full the same time significantly reduc- advantage of as many traffic opera- ing delays when at-grade intersec- tions improvements as possible, tions are replaced with grade separa- including: tions. In addition, accidents have been reduced by up to 20 percent. l traffic channeliiation The cost per mile is estimated to be l grade separations between $3 and $4 million, resulting street widening . in benefit/cost ratios between 2:l and reversible traffic lanes . 4:l (Urbanik et al 1990). . intersection widening . railroadgrade separations Implementation: The design, con- . leftlright turn lanes struction, and operation of a super . improved traffic control devices street arterial will be undertaken by l two-way turn lanes the agency having the administrative l removal of parking jurisdiction for the arterial in ques- l turn prohibitions tion. The design and construction of l lighting improvements such a facility will likely be expensive l one-way streets and time-consuming, as it is treated . bus turnout bays in the same way as any large highway construction project. It is thus not a These measures generally provide quick solution to recurring conges- spot or localized reductions in con- tion. There are several important gestion. constraints that must be addressed in implementation of super arterial Benefits/Costs: Implementation of considering this type of improve- streets is beneficial for those super arterial streets is similar in con- ment, including land acquisition, cept to the reconstruction and expan- opposition from abutting land own- suburban highway systems that sion of freeways to increase capacity ers, access to existing and future land are based upon arterial networks and to improve traffic flow. However, parcels, and environmental problems super arterial streets provide even (such as wetlands). Importantly, for that will not accommodate greater increases in capacity. This those areas not in compliance with freeway facilities. approach is beneficial for those subur- air quality standards, addition of ban highway systems that are based super arterial capacity will be subject upon arterial networks that will not to conformity review to show that accommodate freeway facilities. additional road capacity will not fur- Converting a typical suburban arteri- ther deteriorate the quality of the al with signalized intersections to a region’s air. super street could increase capacity by as much as 50 to 70 percent, while
REFERENCE Henk, R., C. Poe, and T Lomax. 1991. An Assessment of Strategies for alleviating Urban Congestion, Report 1252-lF, Texas Transportation Institute, Texas A&M University, College Station, TX, November. Urbanik, T., et al. 1990. Considerations in Developing a Strategic Arterial Street System, Research Report 1107s5F, Texas Transportation Institute, Texas A&h4 University, College Station, TX, November.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM Intersection Improvements Transportation Engineers (ITE) that Description:Intersections often can should be incorporated wherever be designed or redesigned to improve possible (Institute of Transportation the flow of vehicles and to assure the Engineers 1992; Neuman 1985) They safepassage of pedestrians and bicy- are: cles.Not only will such a design pro- 1. Reduce the number of conflict vide better geometries, but the use of points among vehicular move- traffic control devices such as stop ments. Intersections often can be and yield signs can provide signifi- 2. Control the relative speed of cant improvements in capacity and designed or redesigned to improve vehicles both entering/leaving an safety. As noted in the section on intersection. the flow of vehicles and to assure bicycle and pedestrian networks on page 104, however, not all intersec- 3. Coordinate the type of traffic the safe passage of pedestrians tion improvements might be made to control devices used (such as stop and bicycles. The use of traffic facilitate the movement of vehicles. signs or traffic signals) with the control devices such as stop and Traffic calming techniques that volume of traffic using an include intersection modifications are intersection. yield signs can provide significant designed to lower the speed of motor 4. Select the proper type of intersec- Improvements in capacity and vehicles and facilitate the movement tion to serve the volume of traffic of pedestrians and bicycles. safety being served. Low volumes can be Therefore, intersection improvements served with no controls, whereas must be considered from a broad per- high levels of traffic may require spective on what a community wants more expensive and sophisticated to achieve in enhancing mobility and treatments such as turning lanes or accessibility. even at grade separation structures. Benefits/Costs: The costs associated 5. When traffic volumes are high, with planning and implementing this separate right turn and/or left turn technique are modest, and vary lanes may be required. depending upon the complexity and the extent of the improvement. The 6. Avoid multiple and compound benefits, however, are possibly sub- merging and diverging maneuvers. stantial due to the reduction in traffic Multiple merging or diverging conflicts between different vehicle requires complex driver decisions flows and between pedestrians/bicy- and creates additional conflicts. cles and vehicles. There are no readi- 7. Separate conflict points. ly available data to define the specific Intersection hazards and delays are costs and benefits of intersection increased when intersection improvements, because there is such maneuver areas are too close a wide range of circumstances that together or when they overlap. are appropriate for this action. These conflicts may be separated Implementation: In designing and to provide drivers with sufficient improving arterial intersections that time (and distance) between are at-grade, 11 principles have been successive maneuvers. established by the Institute of
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY 8. Favor the heaviest and fastest where there are flows. The heaviest anapplicabled fastest volumes of traffic trav- flows should be given preference eling at different speeds. For exam- in intersection design to minimize ple, separate turning lanes should hazard and delay. be provided for turning vehicles. 9. Reduce area of conflict. Large . Design for access by pedestrians intersections cause driver confu- and bicyclists. For example, when sion and inefficient operations. there are pedestrians crossing wide When intersections have excessive streets, refuge islands should be areas of conflict, us channeliza- e provided so that a large number of tion. travel lanes have to be crossed at a time (see section on pedestrian l0. Segregate nonhomogeneous flows. and bicycle networks). Separate lanes should be provided . REFERENCES Institute of Transportation Engineers. 1992 Traffi Engineeringc Handbook, Fourth. Edition, Washington D.C. Neuman, T. 1985. Intersection Channelization: Design Guide, NCHRP Report 279, Transportation Research Board, Washington D.C., November.
One-Way Streets One-way streets are generally oper- Description:Although most streets ated in one of three ways: and highways are designed for use by . A street on which traffic moves in two-way traffic, high volumes of traf- one direction at all times. In major activity center, such as fic and vehicle conflicts often lead to l A street that is normally one-way, the central business districts of consideration of one-way traffic regu- but at certain times may be operat- lations. In major activity centers, cities with large traffic volumes ed in the reverse direction to such as the central business districts and closely spaced intersections, provide additional capacity in the of cities with large traffic volumes predominant direction of flow. one-way traffic regulations are and closely spaced intersections, one- way traffic regulations are frequently l A street that normally carries two- frequently used used because of traffic signal timing way traffic, but which during peak considerations and of limited avail- traffic hours may be operated as a ability of other options to improve one-way street usually in the heav- street capacity. In the development of ier direction of flow. Such a street new activity centers such as shopping may be operated in one direction centers, sports arenas, industrial during the morning peak hour and parks, and so on, one-way regulations in the opposite direction during are frequently incorporated into origi- the evening peak hour, with two- nal street and traffic plans. way traffic during all other hours.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM Benefits/Costs: One-way streets can The benefits of one-ways streetsy are s provid increasee capacitd oy r facili- mixed They. y could d result in t improved tate multimodale improvementsl as , safety as y they reducey vehicle-pedestri-e they (Institut: of Transportatione an and vehicle-vehicle conflicts at e s Engineer 1992)s intersection, prevent pedestrian, t entrapment betweent opposingn gtraffic l Reduce intersection delay causedn s streams, and, improve ae driver's field’ s by vehicle turning-movemente t con- of vision at n intersection approaches.n flicts ands pedestrian-vehicle con- e However, they, mayy also leado d to safety flicts. problems ass they mayy increase aver-e ) Allow w lane-width adjustmentsh that s age traffic speedsc ands lead tod wider One-Way Street increase thee capacitye ofy existing pedestrian roadwayn crossings One-. lanes, or , provide ane additional way streetss could d also resulto in n t more lane fore r motor traffic bicycles,, cost-effective operatione as , they pro-y buses os r parking. vide additional capacityl toy satisfy l Permit improvementst in publics traffic requirementsc for r a s substantial transit operationst such, h as routings period ofd time withoute larget capitale without turnbackt k loops (out ont expenditures. And they. couldy d also one street andt return onn the para-e meet othert communityr objectivesy s as llel streets).l they savey e sidewalks, trees , ands other valuable frontagee assetse thats couldt otherwise be loste becauset ofe the One-way streets could result /n improved safety as they reduce vehicle-pedestnan widening of existingg two-wayg streets.y and vehicle-vehicle conflrcts at intersections. However, they may also lead to safety However there, ise s a possible adversee problems as they may increase average traffic speeds and lead to wider pedestrian impact t on some businesses and com-s merce e in general whenl n one-way roadway crossings. streets are initiated.s l Permit turnst froms more than n one Implementation: The amount t of lane e and doing sog at more intersec- data a to be collected and d analyzed ind tions thans n would d be possible withe planning forg r one y traffic regula-c two-way operation.y tion wills dependl largelyd ony the sizee l Redistribute traffic e to relievec con-e and complexity of they one-waye sys-y gestiono on n adjacent streets.t tem m under donsideration.r As a gener-. al rule two-way, streetsy shoulds bed . Simplify trafficy signalc timingl by:g made one-way onlyy y when: l Permitting improvedg progressived . It t can be shown n that at specific movement oft traffic. traffic problemc will bel alleviated or d
l Reducing multiphaseg signale the overalle efficiencyl of the y trans-e requirements by makings minorg portation systemn willm bel improved. street one-ways awayy from l One-way operationy isn s more complex x areas s or intersections. desdirable ande cost-effective than e alternative solutions.e
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY .Parallel streets of suitable capacity, . Proper transit service can be main- preferably not more than a block tained. apart, are available or can be con- .The effect on businesses and access structed. to community centers is known . Such streets provide adequate and mitigation provided for. traffic service to the area traversed . The impact on nonmotorized and carry traffic through and transportation is minimal. beyond the congested area. One-way streets are sometimes l Safe transition to two-way opera- introduced as part of a major detour tion can be provided at the end scheme that is made permanent after points of the one-way sections. the project is constructed.
References Institute of Transportation Engineers. 1992. Traffic Engineering Handbook Fourth Edition, Washington D.C.
Reversible Traffice Lanesc a two-way street operate one-way Description Arterial: routes that are during that period. normally operated as two-way streets, Benefits/Costs A reversible-lane: particularly those in urban areas, can system is one of the most efficient experience much greater peak-hour methods of increasing rush-period With the reversible lane system, traffic volumes in one direction than capacity of existing streets (Institute in the other. With the reversible lane of Transportation Engineers 1992). one or more lanes are designated system, one or more lanes are desig With minimal capital costs, it takes for movement one-way during nated for movement one-way during advantage of unused capacity in the part of the day and in the opposite direction of lighter traffic flow by part of the day and In the opposite direction during another part of the making one or more of those lanes direction during another part of day. On a three-lane road, for exam- available to the heavier traffic flow. the day. ple, the center lane might normally The result is that all lanes are better operate as a two-way left-turn lane, used. The system is particularly but during the peak hour operate in effective on bridges and in tunnels, the direction of greater flow. One of where the cost to provide additional the outstanding examples of multiple capacity would be high and perhaps reversible lanes is the eight-lane impossible. Some disadvantages are: Cuter Drive in Chicago, which oper- Capacity is reduced for minor ates a 6-2 lane split during peak traf- . flows during peak periods. fic periods. The purpose of the reversible lane system is to provide an . Reversible lanes frequently create extra lane or lanes for use by the operational problems at their dominant direction of flow. Two termini. increasingly used methods are to reverse the flow of an entire street during peak-hour periods or to make
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM . . Concentratedenforcementefforts between the normal and reversed- may be needed to prevent viola- lane conditions. Installation of a tions of the lane-use regulations. reversible-lane system with sufficient end-point capacity may simply Implementation Several: factors aggravate or relocate the congestion should be considered in determining problem. whether reversible lanes are justified: Once a reversible system is deemed Evidence of congestion. If the level necessary and feasible, the method of of service during certain periods designating lanes to be reversed and decreases to a point that it is evident that traffic demand is in excess of the direction of flow must be select- ed. Three general methods are used: A reversible-lane system is one of actual capacity, the possibility of 1) special traffic signals suspended using reversible lanes should be con- the most efficient methods of over each lane, 2) permanent signs sidered. increasing rush-period capacity of advising motorist of the changes in Time of congestion. The periods traffic regulations and the hours they existing streets. during which congestion occurs are in effect, and 3) physical barriers, should be periodic and predictable. such as traffic cones, signs on Traffic lanes can usually only be portable pedestals, and movable barri- reversed at a fixed time each day. ers (see discussion in HOV section). Ratio of directional traffic volumes. Although reversible-lane operation Lane reversal requires that the addi- is principally used on existing streets tional capacity for the heavier direc- and roadways, it can also be designed tion be taken from the traffic moving into new streets, freeways/express- in the opposite direction. Traffic ways, bridges, and tunnels. counts by lane will determine Applications to older limited-access whether the number of lanes in one facilities is difficult because most such direction can be reduced, how many roadways have fixed medians separat- lanes should be allocated to each ing the two directions of traffic. By direction, and when the reversal constructing special median crossing should begin and end. On major locations and by properly using traffic streets, there should be at least two control devices, however, even these lanes for traffic flowing in the minor facilities can be used in a reversible direction. manner. Obviously, extreme care Capacity at access points. There must be exercised to maintain safe must be adequate capacity at end operation. Another possible applica- points of the reversible-lane system, tion is the use of movable barriers with an easy transition of vehicles (see HOV discussion). .
Reference Institute of Transportation Engineers. 1992. Traffic Engineetirrg Handbook, Fourth Edition, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Arterial Access Management l Discourage additional commercial Description: In a general sense, sprawl and strip development access management is the control of l Assess the traffic impacts of all the spacing, location, and design of proposed developments driveways, medians/median openings, Minimize conflicts between local intersections, traffic signals, and free- . and through traffic by regulating way interchanges. Access manage- land uses, building setbacks, drive- ment elements often include one or way openings, and front or rear more of the following: service drives l physically restricting left turns l Provide efficient accessibility to . restricting curb cuts and direct retail uses to minimize traffic con- access driveways flicts . separating obvious conflict areas l Establish driveway location and l eliminating parking spacing standards such as distance from intersections, joint use of l locating intersections at no less driveways, spacing of driveways to than minimum intervals avoid conflicts, etc. . constructing frontage roads to col- l Incorporate access management lect local business traffic and fim- concepts into zoning and subdivi- Access management is the control neling it to nearby intersections sion regulations of the spacing, location, and The importance of access manage- Another example of access man design of driveways, medians/ ment is seen in the following statis- agement that includes a variety of median openings, intersections, tics. Fifty-two percent of all accidents recommended actions is found in in Colorado were access-related; 32 Penfield, a suburb of Rochester, New traffic signals, and freeway percent of all fatalities. In Oklahoma, York (New York State DOT 1996). interchanges. 57 percent of the accidents are The different types of actions found access-related; in Michigan 55 per- in this program are: cent. Better managing arterial access could thus provide significant safety Access Management Changes benefits to a community. l Driveway consolidation and sharing A good example of the role that l Driveway spacing and design corridor access management can have l Comer clearance spacing is found in a corridor plan for a major l Parking consolidation and access thoroughfare in suburban Detroit. l Alternative parking The access management plan for this requirements corridor was intended to meet the following goals: (Michigan DOT Land Use Modifications 1995) l Conditional land uses l Front setback reductions l Discourage commercial develop l Density and intensity incentives ment along the corridor where lot l Buffers and lot coverage depth is inadequate to provide turning truck movements
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM l Dimensional requirements closed. Without an access manage- l Landscaping ment program along arterial high- l Use limitations for corner ways, capital investment for roadway properties improvements and/or relocation is Transportation Improvements often required. This cycle relates to satisfying traffic demands that are l Raised medians often a result of increased business l Access roads The major benefit of access man- activity, which is influenced by l Right turn lanes agement occurs with the resulting improved traffic conditions, which l Signal location and timing leads to further traffic demands. The reduction in accidents. l Directional signage modifications number of conflict points among Capital improvements vehicles rises as a result of an increas- l Project betterments ing number of driveways, causing the l Developer agreements/ capacity at a specific level of service mitigation to diminish. Vehicle delay increases, l Mitigation fees within zone and safety and comfort are reduced. Benefits/Costs The major: benefit of One of the potential consequences access management occurs with the of closing medians or not allowing resulting reduction in accidents. multiple driveways is the negative Figure 2-12 shows the relationship impact on businesses that are adja- between accident rates and the num- cent to the arterial. Several studies ber of curb cuts per mile as deter- have shown that, depending on how mined in two studies (La11 et al 1995; access management is implemented, Gluck et al 1996). Figure 2-13 shows these losses can vary. In one Florida the results when median openings are DOT district, for example, 63 percent
Figure 2.12: Accident Rates and Number of Curb Cuts Per Mile
- Access per Mile
<------CltY ---> <------Parkway -----> Llmlts
ource. La// et al 1995
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY
References Federal Highway Administration. 1993. Proceedings of the First National Access Management Conference, Vail, CO, Report HEP-22/11-93( 350)) Washington D.C. Florida Department of Transportation (DOT). 1994. Model Land Development & Subdivision Regulations That Support Access Management, Tallahassee, FL, Jan. Florida Department of Transportation (DOT), Crush Comparisons, Median Treatments, Tallahassee, FL, undated. Gluck, J. et al. 1996. Impacts of Access Management Techniques, Interim Report, NCHRP, Transportation Research Board, Washington D.C., January. Koepke, EJ. and H.Levinson. 1992. Access Management Guidelines for Activity Centers, NCHRP Report 348, Transportation Research Board, Washington D.C. Lall,B.K., et al. 1995. Analysis of Traffic Accidents within the Functional Area of Intersections and driveways Technical Report TRANS l-95, Portland State University, Portland, OR Michigan Department of Transportation. 1995. M59 Corridor Plan, Lansing, MI, May. New York State Department of Transportation (NYSDOT).1996. Best Practices In Arterial Management, Corridor Management Group, Albany, NY, August. Williams, K. and J.R. Foster. 1996. Land Development Regulations that Promote Access Management, NCHRP Synthesis 233, Transportation Research Board, Washington D.C.
Traffic Calming and Street Space With lower speeds and vehicular vol- Management umes, the area’s living environment Description: Traffic calming is a con- becomes more hospitable to residents, cept that seeks a more harmonious pedestrians, and bicyclists. For exam- relationship between vehicular traffic ple, the traffic calming steps that are and people. The definition of traffic being considered in Albany, New calming according to the Institute of York include: (Capital District Traffic calming is a concept that Transportation Engineers is as fol- Transportation Commission 1995) seeks a more harmonious relation- lows: Traffic calming is the combination l high visibility crosswalks of mainly physical measures that reduce ship between vehicular traffic and l allowing on-street parking the negative effects of motor vehicle use, people. l providing bike lanes alter driver behavior and impose condi- l reducing curb radii at intersections tions for non-motorized street users l lower speed limits (Lockwood 1997). Comprehensive l limiting/prohibiting right turns traffic calming strategies consist of a on red variety of techniques designed to re- l sidewalk extensions (both allocate trips, either by mode or maintaining and reducing route, occurring within an urban or number of lanes) suburban street network. Within the l pavement narrowing (both United States, traffic calming mea- maintaining and reducing sures are more focused towards lower- number of lanes) ing vehicle speeds and reducing traf- speed bumps/tables fic volumes, most often with physical . l stop signs/all-way stops or operational changes to the streets diagonal diverters at intersections themselves (Institute of . (eliminates through movements) Transportation Engineers 1993). l street closures
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY In West Palm Beach, Florida, traffic calming actions have been classified into four major groups: (City of West Palm Beach 1996)
Actions Most Effective For Reducing Speeding
l Narrowing the street (choke points) l Angled slow points (chicanes) l Bulbouts at intersections l Roundabouts (or traffic circles) Traffic Circle or Roundabout with Curb Extem-tons l Yield points, midblock and The basic concepts inherent in intersection traffic calming and street space man- l Speed humps (or speed tables) agement have been discussed for Actions Most Effective In Reducing many years by planners and urban Issues that must be addressed in Cut-Through Traffic designers [see, for example, (Moudon
l Diagonal road closure 1987; Appleyard 1981; Buchanan the engineering of traffic calming (intersection diverters) 1963)]. Recently, traffic calming has include design speed, use of alleys, l Forced turn barriers received renewed attention in the intersection geometry street trees l Partial road closures context of environmental quality and l One-way streets the quality of life in a community and landscaping, street lighting, l Rebuild street with reduced (Johnson 1993; Carlson 1995). In sidewalk width and location, build- pavement width addition, traffic calming techniques l Gateways (perimeter treatments) in the context of neo-traditional ing setbacks, superelevation, con-
l Roundabouts (or traffic circles) neighborhood design have begun to struction centerline of roads, and receive serious attention by traffic Actions Providing the Best engineers (Lemer-Lam et al 1992). trip generation. Landscape Opportunities Issues that must be addressed in the l Roundabouts (or traffic circles) engineering of traffic calming include l Gateways (perimeter treatments) design speed, use of alleys, intersec- l Narrowing the street (choke tion geometry, street trees and land- points) scaping, street lighting, sidewalk l Angled slow points (chicanes) width and location, building setbacks, l Bulbouts at intersections superelevation, construction center- l Mid-block single lane points line of roads, and trip generation. Low-Cost, Immediate Actions Benefits/Costs: The benefits of traf- . STOP signs fic calming can vary by the level and l On-street parking scope of the types of techniques that l Turning movement restrictions are employed. At a broader level, the l Speed humps impact of such an action on trans- portation behavior is similar to that found for improved urban design (dis- cussed in Chapter 5)) auto restricted zones (discussed in Chapter 5), and
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM transit supportive development (dis- Columbia and the results are shown cussed in Chapter 4). Generally, tran- in Figure 2-15 (Zein et al 1997) sit ridership from such areas will be Implementation: Traffic calming higher and auto trips will be lower A study of traffic calming and street management techniques than comparable neighborhoods. can provide important benefits to techniques in Germany showed a Pedestrian/bicycle conflicts with local neighborhoods and shopping vehicles will also be reduced thus significant Increase In community areas. However, constraining the use likely decreasing the number of acci- of the automobile and trucks will interactions when automobile use dents that occur in the area. At the likely be opposed by those worried limited and when more site level, the application of these was a about the impact of such constraints types of techniques can have an friendly pedestrian environment on mobility and accessibility to spe- important impact on the community cific activity centers. A study of such was provided fabric and the interaction among techniques in Europe found the fol- neighbors. A study of traffic calming lowing lessons in successfully imple- techniques in Germany showed a sig- mented projects: (Pressman 1987). nificant increase in community inter- actions when automobile use was lim- . A high degree of public participa- ited and when a more friendly pedes- tion in planning is essential. trian environment was provided . Laws and regulations providing (Eubank-Ahrens 1987). Another enhanced rights for pedestrians study of German traffic calming and bicyclists were an important schemes showed a 20 percent reduc- foundation for the enforcement of tion in accidents, a 50 percent the automobile constraints. decline in serious accidents, through Public acceptance of the concept traffic was discouraged, and a . will occur over time when the “notable decline in the noise level benefits are clearly observable. and in the speed of motor traffic”(Hass-Klau 1990). A study of . Speed bumps and traffic control the impacts of traffic calming mea- devices are being used regularly as sures on accident frequency was con- a means of controlling vehicle ducted in Vancouver, British movement.
Figure 2.15: Accident Reductions for Traffic Calming Measures in British . Design of the street space (through Columbia bricks, paint, street furniture, and / \ fencing) is critical in emphasizing speed Limits quality and human scale. Refuges . Sophisticated visual guidance sys- Muiltiple stop signs tems/kiosks can be used to provide
Speed Humps information to visitors. Narrowlings . Strong political commitment from Chicanes community leaders is an essential Traffic Circles ingredient of success.
percent Reduction in Accidents
Source Zein et al 1997
72 A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY l A stable and continuing fund for l The ability to accommodate maintenance is an important ele- changes in use over time is central ment of a financing strategy. to the vitality of the area. l Traffic calming is integrated with The ingredients of a successful regional and local transit services. traffic calming plan for U.S. applica- tion includes not only these items, l Zoning should be used to reinforce but also a close relationship between the types of land uses that are land use plans, transportation plans compatible with the pedestrian and programs, and public involve- environment. ment (Jarvis 1993).
References Appleyard, D. 1981. Livable Streets, Berkeley: University of California Press. Buchanan, C. 1963. Traffic in Towns, London. Capital District Transportation Commission. 1995. Making the Capital District More Bicycle- and Pedestrian-Friendly: A Toolbox and Game Plan, Albany, NY, October. Carlson, D. 1995. At Road’s End, Transportation and Land Use Choices for Communities, Surface Transportation Policy Project, Washington D.C.. City of West Palm Beach. 1996. Traffic Calming for West Palm Beach: A Catalog of Options, West Palm Beach, FL, March. Eubank-Ahrens, B. 1987. “A Closer Look at the Users of Wonnerven,” in A. Moudon, Public Streets for Public Use, New York: Columbia University Press. Hass-Klau, C. 1990. The Pedestrian and City Traffic New York: Bellhaven Press. Institute of Transportation Engineers (ITE) 1993. Guidelines for the Design and Application of Speed Bumps: A Proposed Recommended Practice, Washington D.C. Jarvis, F. 1993. Site Planning and Community Design for Great Neighborhoods, Washington D.C.: Home Builder Press. Johnson, E. 1993. Avoiding the Collision of Cities and Cars, Urban Transportation Policy for the Twenty-first Century,American Academy of Arts and Sciences, Washington D.C. Lemer-Lam, E., et al, 1992.“Neo-‘Traditional Neighborhood Design and Its Implications for Traffic Engineering,” ITE Journal, January. Lockwood, I. 1997. ITE Traffic Calming Definition, ITE Journal, July. Moudon, A. 1987. Public Streets for Public Use, New York: Columbia University Press. Pressman, N. 1987. ‘The European Experience,” in A. Moudon, Public Streets for Public Use, New York: Columbia University Press. Zein, S., et al. 1997,“Safety Benefits of Traffic Calming ,” Paper presented at the 76th Annual Meeting, Transportation Research Board, Washington D.C.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM ARTERIALS AND LOCAL STREETS: Interconnected Signals-Specific OPERATIONS improvements could include one or Similar to the tools discussed under more of the following: interconnect- freeway operations, many of the tech- ed pre-timed signals, traffic actuated niques and technologies mentioned signals, interconnected actively in this section are components of managed timing plans, and master intelligent transportation systems controls. (ITS) strategies. Trends in urban traf- Traffic Signal Removal-Many traffic fic management suggest that one of signals are no longer justified in the most important tools in the con- urban areas due to changes in traffic gestion management toolbox will be patterns. Many of these intersections improving system operations. can be better controlled by two-way Traffic Signal improvements stop control. For those situations where peak traffic flows necessitate Description: Of the approximate continued signalized control, but off- 240,000 urban signalized intersections peak traffic does not, conversion of in the United States, about 148,000 control from full to flashing operation need upgrading of physical equipment can provide significant reductions in Traffic signal improvements and signal timing optimization, while delay and congestion during the off- generally provide the greatest another 30,000 are only in need of peak times. Removing traffic signals payoff for reducing congestion signal timing optimization (Federal can reduce vehicle delay and decrease on surface streets Traffic signal Highway Administration 1987). Improvements include: unwarranted stops. However, experi- Traffic signal improvements generally ence has shown that removing an l Equipment update provide the greatest payoff for reduc- existing traffic signal will likely be ing congestion on surface streets. l Timing Plan Improvements opposed by many groups, especially There are a number of relatively basic l Interconnected Signals nearby residents. improvements that can and should be l Traffic Signal Removal made to improve traffic flow on arte- Traffic Signal Maintenance-Traffic rials. They include: signals are often installed with little l Traffic Signal Maintenance attention given to the cost and Equipment update-In this case, an procedures required for maintenance. inventory of existing traffic control This is a problem that has become devices should be made to determine particularly critical in recent years if new, more modem equipment can as more sophisticated trafhc control replace them. This would allow for devices are installed. Several the planning of a more comprehen- categories of maintenance should be sive set of strategies to improve traffic considered: flow. Preventive maintenance, to be Timing Plan Improvements--This . performed at regular intervals in action would require a data collection order to avoid unnecessary prob- effort in order to update the traffic lems; signal timing to correspond to current traffic flows. Appropriate pre-timing of signals has been very successful in improving traffic flows.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY l Response maintenance, which program to improve traffic signals includes quick response to emer- resulted in reductions in average gency situations as well as trouble delay per signal cycle from between shooting; and 14 to 29 seconds (City of Tucson 1991). A similar effort for northern l Design modification, which deals Virginia resulted in benefit/cost ratios with the need to monitor new in the 2O:l range for signal improve- equipment as well as signals placed ments. The annual user benefits (in in new locations in order to ensure terms of travel time savings and fuel safe and effective operation. costs) were estimated to be just over Benefits/Costs: Improvements to $7 million (Virginia DOT 1991). An traffic signalization is one of the most aggressive program of signal timing Improvements to traffic signaliza- cost-effective tools in the Toolbox. optimization in California indicated a tron is one of the most cost- Appropriately designed and function- benefit-cost ratio of 58 to 1. Applied ing traffic signals provide for orderly to 3,172 signals in the state, the pro- effective tools in the Toolbox. traffic movement, interrupt heavy gram resulted in over a 15 percent traffic at intervals to allow pedestri- reduction in vehicular delays and a ans and connecting-street traffic to 16 percent reduction in stops over cross, increase the traffic-handling three years. Overall travel times capacity of an intersection, and through these systems dropped by 7.2 reduce the frequency of accidents. percent. The reduction in fuel expen- Sometimes traffic signals can have ditures (8.6 percent) alone produced the opposite effect of that intended. savings almost 18 times the total cost Experience has shown that although of implementing the signal retime signals can decrease the number and program. severity of right-angle collisions, they Typical costs associated with traffic might increase the number of rear- signalization improvements include: end collisions (Institute of (Environmental Protection Agency Transportation Engineers 1992). 1991) However, even given such a possibili- I ty, the cost effectiveness of improved \ Equipment or software updating...... $2,000-$3,000 per signal signal timing is significant primarily Timing plan improvements ...... , . $300-$400 per signal due to the reduced delay at intersec- Signal coordination tions. Several studies have indicated and inter-connection...... $5,000-$13,000 per signal the level of such benefits. Texas Signal removal . _ ...... $300-$400 per signal implemented a statewide signal syn- chronization program and concluded that after 26 projects, and $1.7 mil- lion in expenditure, there was a 19.4 percent reduction in delay, an 8.8 percent reduction in the number of stops, and a 13.3 percent reduction in fuel consumption (Fambro et al 1995). The overall benefit/cost ratio was 38:l. In Tucson, AZ a regional
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM Implementation: The first action local traffic engineering department.] required to improve the traffic signal Although the methods available to system in an urban area is to invento- upgrade traffic signals are relatively ry existing signals, the traffic flow straightforward, this action is often conditions being controlled, and the overlooked by public officials as an level of service being provided. effective way to improve traffic flow. Traffic and its relationship to the In fact, there are cases where public existing traffic signal system must be officials may react to public pressure analyzed to determine if the system is for installing new traffic signals faster current and still appropriate. Then, a than they will to improve existing comprehensive policy should be signals. Installing new signals could, developed to implement the actions in fact, further exacerbate the prob- described above. Traffic signal loca- lems of congestion in a particular tions and timing should be developed area. The strategy having the greatest in accordance with state and local potential for improving system opera- warrants established for that purpose tions is providing better connections (ITE 1992). [For more information or interconnectivity between signals. about these warrants, contact your
References City of Tucson. 1991. Tucson Transportation System Planning Study, Find Report, Transportation Planning Division, April. Environmental Protection Agency. 1991. Transportation Control Measure Information Documents, Washington DC. Fambro, D. et al. 1995. Benefits of the Texas Traffic Light Synchronization Grant Program, Texas Transportarion Institute, Report No. 0280-1F Texas A&M University. Federal Highway Administration. 1987. Urban and Suburban Highway Congestion, Working Paper No. 10, Washington, D.C., December. Institute of Transportation Engineers (ITE). 1992. Traffic Engineering Handbook, Washington D.C. Virginia Department of Transportation. 1991. VASTOP Final Project Report for the Northern Region, August.
Computerized/Interconnected settings of traffic actuated signals, Signal Systems and 3) incorporating advanced traffic Computerized traffic signal systems Description: Computerized traffic control functions by using master usually involve: signal systems usually involve three computers. This latter includes 1. Coordinating groups of signals elements: 1) coordinating groups of increased timing plan flexibility, 2. Optimizing the signal timing signals by using either inter-connec- dynamic traffic responsive control parameters of pre-timed signals tion or highly accurate timebased features, and on-line traffic petfor- coordinators, 2) systematically opti- mance monitoring and control system 3. Incorporating advanced traffic mizing the signal timing parameters components operation. control functions. of pretimed signals or the interval
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Benefits/Costs: Project experience Table 2.4 shows the results from a from around the United States indi- comprehensive signal interconnec- cates that: tion effort in Denver. As shown, travel time reduction on the Denver l Interconnecting previously un- arterial corridors ranged from 7 to 22 coordinated signals or pretimed percent (Denver Council of signals, and providing newly opti- Governments 1995). A similar pro- mized timing plans and a central gram in Richmond, Virginia saw a master control system can result in reduction in travel time ranging from a reduction in travel time ranging 9 percent on one corridor to 14 from 10 percent to 20 percent. percent on another; a 14 percent to . Installing advanced computer con- 30 percent reduction in total delay; trol has resulted in about a 20 per- and a 28 percent to 39 percent cent reduction in travel time when reduction in stops (Virginia DOT compared to interconnected pre- 1994). A national effort to improve timed signals operating with old coordinated traffic signalization timing plans. A national effort to improve coordinated signalization demonstrated that . Installing advanced computer con- trol has resulted in a 10 to 16 per- signal retiming projeas can be extremely cost-effective. cent reduction in travel time when compared to non-interconnected, demonstrated that signal retiming traffic actuated controls. projects can be extremely cost- effective, with benefit/cost ratios . Installing advanced computer con- conservatively estimated at 10: 1 trol, when compared to intercon- when considering fuel savings only. nected multi-dial pretimed control When the benefits of reduced delay with relatively active signal timing and stops are added, these ratios management, has resulted in an 8 double to 20:l (Federal Highway to 10 percent reduction in travel Administration 1987). time. l Optimizing traffic signal timing plans, when compared to previous- ly interconnected signals with var- ious master control forms and varying previous signal timing qualities, has resulted in a 10 to 15 percent reduction in travel time.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM
Additional analysisis l of signas improve-l ment s inn Houston include[see e table nn nexti t colum (Henk, & Poe and Isolated/uncoordinated Local coordinated 10% Lomax 1991). Isolated/Uncoordinated Monitored/coordinated 15%
Implementation: The implementa- Isolated/uncoordinated Central coordinated 25% tion ofn coordinated trafficd signalc Local coordinated Monitored/coordinated 5% systems shoulds bed based d on sound Local coordmated Central coordmated 15% analysis of thes appropriatee charater-e Monitored Central coordmated 10% istics of suchs h a system. Several. computer programsr are available to e instances, close , interjurisdictionale develop optimalp sisgnall timingl strate-g cooperation isn s necessary to assurey gies. One. e of the most-usede programsd that technologiest are beings appliedg ind is s called Transyt-7Fd and providesF a consistent manner.t Even. inn n the useful guidancel one optimal signall absence ofe ITS S programs, , such h coop coordination strategiesn Another. reation is s n critical for r l success. The. package TRAF-Netsim, can be, used Denver exampler describede previouslyd to assess thes benefitse of signals coordi-l shows s the importante rolet e that ant nation Increasingly. computerized, agency “y convener (in” thisn cases the, signal coordinationl hasn become an metropolitan planningn organizationg important elementt of regionalt trafficl can have e in getting differentg jurisdic-t management schemes.t In these. tions tos interconnect signalt systems.l ......
References Denver Regional Council of Governments. 1995. Signal Systems Improvements, Regional, Report, Denver, CO, August. Federal Highway Administration. 1987. Urban Traffirafic Congestionc - A Perspective to the Year 2020, San Francisco, CA, FHWA Region 9, San Francisco, September. Henk,& R.H., C.M. Poe, and T. Lomax 1991.. An Assessment o Strategies for Alleviatingf Urban Congestion, Research Report 1252-1F Texas, Transportation Institute, College Station, Texas. Schrank, D., and T Lomax. . 1996. the e Effect of t Operational Improvementsl in thes Houston Area," Transportation” Research Record 1564, Transportation Research Board, Washington D.C. Virginia Department of Transportation. 1994. CBD Traffic Signalc System in the City of Richmond, Richmond, VA, October.
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM Arterial Surveillance and lance data for a variety of traffic man- Management agement functions. Traffic surveil- Description: Arterial surveillance lance data is used in monitoring traf- and management is very similar in fic conditions with computer graphics concept to the freeway and integrated displays, critical intersection control, freeway/arterial management systems traffic responsive control, develop discussed earlier in this chapter. This ment of ad hoc timing plans for non- action could include the following recurring situations, transportation kinds of efforts: planning, and system performance evaluation. As a general policy, traffic Incident detection and follow-up . system detectors are placed in each action to remove incidents: marked approach lane at intersec- l Service patrols tions of arterial streets. Closed circuit l Roving tow vehicles at key sites television is used to monitor traffic l Motorist information system, flow, and changeable message signs including radio announcements, and highway advisory radios are used citizen-band radios and cellular to convey important traffic informa- phones tion to motorists. This system has l Incident teams Arterial surveillance and manage- given transportation officials the l Real time transit passenger ment could include: capability of responding more effec- information systems at bus stops, l tively to short- and long-term Incident detection kiosks, and via telephone changes in traffic demand, develop l intersection surveillance and l Intersection surveillance and monitoring ing new signal timing plans, evaluat- monitoring, using: ing current timing strategies, and l Parking control and l Loop detectors identifying equipment malfunctions. management l Interconnected signal systems Benefits/Costs: A major cost of l l Integration of freeway and Video monitoring of key planning and implementing an effec- arterial management programs intersections tive arterial surveillance and manage- . Traffic surveillance and . Parking control and management ment system is associated with inter- metering on key arterials, with greater section control devices and the oper- enforcement of parking regulations ational costs of monitoring road per- on designated through arterials formance [described earlier in this l Integration of freeway and arterial chapter]. The benefits to be derived management programs (as from such a program are significant. described earlier in this chapter) The following Boston case study illus- trates the possible magnitude of such Traffic surveillance and metering benefits (Dimino, Bezkorovainy, and The City of Anaheim, California Campbell 1987). In August, 1986, has implemented an integrated traffic Boston initiated Phase I of a Traffic management system that is one of the Relief Program (TRP). The program best examples of this action (JHK & was an interagency effort of the Assocs. 1992). One of the most dis- Boston Transportation Department tinctive features of this system is the and the Boston Police Department to very extensive use of traffic surveil- provide increased enforcement of the
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY city’s traffic and parking regulations increase in speeds. As could have on congested roadways in downtown been expected, because average speeds Boston (see enforcement section at increased, travel times decreased in the end of this Chapter). The TRP the range of 28 to 30 percent for three was a reaffirmation of the city’s phi- of the routes surveyed, and an 18 per- losophy that major arterials primary cent decrease was noted on another. function is the movement of traffic This resulted in a time savings to during periods of heavy traffic flow. A motorists of over 1,200 hours per day. 30.day trial period concentrated on An air quality analysis for carbon three corridors. The following actions monoxide showed an overall improve- A major cost of planning and were taken in the corridors: ment of 15 percent to 18 percent as implementing an effective arterial measured by eight-hour concentration l No-stopping zones were estab- surveillance and management standards and a 13-33 percent lished along most portions of improvement in one-hour concentra- system is associated with the three arterials from 7 a.m. to tions. The program was well received 7 p.m. intersection control devices both by the public and the press. The l Over 180 parking meters were number of parking violations was and the operational costs of removed. reduced by nearly 60 percent. monitoring road performance. . Cab stands, tour bus stops, and Although not sophisticated by City of handicapped parking spaces were Anaheim standards, this effort in relocated to alternate locations. Boston illustrates what can be achieved when arterial operations are Particular problem areas, such as . viewed from a systems perspective. queuing at large garages, received remedial treatment. Implementation: The planning and implementation of an arterial surveil- Enforcement activities featured a . lance and management system can be close working relationship between a major undertaking. The develop- the police department (12 motor- ment of such a system must be coor- cycle officers) and the enforce- dinated with a number of areawide ment division of the Transpor- programs. They must be developed in tation Department (20 meter cooperation with all relevant local maids). They were instructed to jurisdictions, property abutters who keep traffic moving and not to will be affected, business interests, hand out tickets, unless necessary. local elected officials, and citizen The effectiveness of the program groups. was evaluated by collecting travel time data and traffic counts, The following keys to successful recording parking violations, and implementation were associated with analyzing the collected data. the Anaheim project: (JHK & Assocs 1992) The most significant increase in travel speeds occurred in the after- l Incremental implementation noon showing approximately a 28 which allowed the city to move percent increase. At 7 a.m., these forward at a reasonable pace efforts resulted in only a 6 percent
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM .City officials and officials from all .Risk was recognized as part of the concerned agencies participated effort to move forward; some directly in all aspects of project degree of risk was needed in implementation exchange for significant opportuni- ties to improve the system . Flexibility in adjusting to new technologies, funding availability, l The lead agency must seek out and actions of other agencies was funding sources and pursue funding critical directly, and importantly leverage these funds against contributions .Successful interagency cooperation was the most impressive and from other sources important lesson
References JHK & Assocs.1992. City of Anaheim lntegrared Traffic Management System Demonstration Project, FHWA Report DOT-T-93-13, Federal Highway Administration, April. Dimino, R., G. Bezkorovainy, and B. Campbell. 1987. “A Successful Traffic Relief Program,” ITE Journal, Institute of Transportation Engineers, Washington D.C., Aug.
Turn Prohibitions slow vehicles should be removed Description: Conflicts between turn- from high-speed flows ing vehicles and pedestrians and . Safe refuge should be provided for between turning vehicles from oppos- pedestrians and other nonmotor- ing directions can cause congestion ized travelers. delay and safety problems at intersec- It is not always necessary to pro- tions and driveways. Prohibiting turns hibit turning movements at all times is a means of eliminating such con- in order to alleviate a congestion or The most cited reasons for pro- flicts and reducing congestion and accident problem caused by turning hibiting turning movements are: accidents. The treatment of turns at vehicles. Turning movements should l reduction in accidents an intersection is undertaken with be prohibited-only during those hours consideration for many concerns, l increased intersection efficiency when data indicate that a congestion including the following that relate l or accident problem exists and when reduced delay most to turning movements: (Pline a suitable alternative route is avail- l reduced conflicts 1996) able. When part-time restrictions are l improved traffic flow . Undesirable movements should be used, signs used to notify motorists of discouraged or prohibited the restrictions must be designed and .Desirable vehicular paths should placed so that the time of the restric- be clearly defined, safe speeds tion is clearly visible to approaching encouraged, and points of conflict motorists. separated At intersections controlled by traf- l High priority traffic movements fic signals, turns can be restricted to and desired traffic control schemes certain phases of the signal operation should be facilitated; stopped or by use of separate signal displays and
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY appropriate signs. This type of turn represented more than 60 percent of restriction is generally most effective the total accidents on the street sec- when a separate lane is provided for tion affected by the construction, the turning vehicles. The signal phasing median construction resulted in a net techniques can be used to eliminate accident reduction ranging from 12 the conflict between turning vehicles percent to 38 percent (see section on and pedestrians or between turning Arterial Access Management). vehicles and opposing traffic. An alternative to turn restrictions Benefits/Costs: The most cited is the designation of a separate lane reasons for prohibiting turning move- for storage of vehicles waiting to ments are: reduction in accidents, make left turns. This traffic control increased intersection efficiency, technique can take the form of “con- reduced delay, reduced conflicts, and tinuous two-way left-turn lanes” improved traffic flow (Pline 1996). which can be used by motorists in Because turn restrictions cause a either direction. Left-turn storage change in travel path, reliable data lanes can also be established with relative to the total impact of turn pavement markings for one direction restrictions on accidents are difficult to obtain. Data compiled in San An alternative to turn restrictions is the designation of a separate lane for storage Francisco indicated that accidents at of vehicles waiting to make left turns. This traffic control technique can take the form four intersections with turn restric- tions were reduced between 38 per- of “continuous two-way left-turn lanes” which can be used by motorists in either
cent to 52 percent. All of the inter- direction. sections were high-volume intersec- tions used by 30,000 to 50,000 of traffic only on approaches to inter- motorists on an average day (Institute sections where left-turning vehicles of Transportation Engineers, 1992). create accident or congestion prob- The prohibition of turning move- lems. Such designation, however, ments at driveways between intersec- might require that parking be prohib- tions is frequently accomplished by ited which could create a need for a construction of a median divider. A study of curb parking supply and study in Wichita, Kansas, reported demand. The advantages of the turn that prohibition of turns between lane must be compared to the impact of possible parking restrictions. intersections by use of a median reduced accidents between intersec- One of the critical issues associat- tions by amounts ranging from 43 ed with restricting turns is the eco- percent to 69 percent during the first nomic impact on businesses that are three years after the median was now not as accessible as before. The installed. During the same period, following results came from a study accidents at intersections where turns which looked at the economic were not prohibited increased by impacts of restricting left turns: amounts ranging from 12 percent to (Cambridge Systematics and JHK & 38 percent. However, because acci- Assocs 1995) dents between intersections originally
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM .Gas stations had statistically studies should consider: significant loss of sales l The amount of congestion and .Retailers of non-durable goods had delay caused by turning move- statistically significant loss of sales ments. . Service businesses showed patterns l The number of collisions involving of loss of sales although the result vehicles making the turning move- was not statistically significant ment. . Durable goods retailers and hotels .The availability of suitable altema- showed weak evidence of loss of tive travel paths if turns are sales restricted. . Grocery stores and restaurants l The possible impact of traffic showed statistically significant diversion on congestion and acci- evidence of increased sales dents at intersections that would be required to accommodate the The costs associated with different traffic diverted by the turning operational strategies are estimated as restriction. follows: (Environmental Protection Agency 1991) l Possible adverse environmental impacts caused by re-routed traffic. Converting two-way streets to one-way ...... $500-$2,000 per block Two-way street left turn restrictions ...... $400 per intenection . The feasibility of alternative solu- Continuous median strip for left turns ...... $2,000 per block tions, such as provision of separate Channelized roadway and Intersections ...... $200-$500 per block storage lanes for the turning move- Roadway and intersection reconstruction ...... Varies widely ments and, at signalized intersec- tions, the use of special turn-move- ment phasing. Implementation: A modest plan- ning effort is required to identify the .The exclusion of buses, taxis, and locations for possible application of bicycles from the turn prohibition, turning prohibitions. A routine depending on circumstances. design and construction process is then implemented, using appropriate design standards. Turn prohibition
References Cambridge Systematics and JHK &. Assocs. 1995. Economic Impacts of Restricting List Turns, Final Report, NCHRP, Transportation Research Board, February. Environmental Protection Agency. 1991. Transportation Control Measure Information Documents, Washington D.C Institute of Transportation Engineers. 1992. Traffic Engineering Handbook, Fourth Edition, Washington D.C. Pline, J. 1996. Left-Turn Treatments at Intersections, NCHRP Synthesis of Highway Practice 225, Transportation Research Board, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY Improved Traffic Control Devices Description: Traffic control devices which include traffic signs and mark- ings are the primary means of regulat- ing, warning, or guiding traffic on streets and highways. Traffic signs fall into three broad functional classifica- tions:( Institute of Transportation Engineers 1992)
l Regulatory signs: used to impose legal restrictions applicable to particular locations and unenforce- able without such signs. Street signs with large, bold letters can improve . Warning signs: used to call traffic flow attention to hazardous conditions, manually, by remote control, or by actual or potential, that would automatic controls that can “sense” otherwise not be readily apparent. the conditions that require special Guide or informational signs: . messages, have applications for all improvements in any type of road used to provide directions to types of roads. motorists, including route designa signing, the intent of which is to Improvements in any type of road tions, destinations, available ser- signing, the intent of which is to pro- provide better information to the vices, points of interest, and other vide better information to the driver, geographic, recreational or cultural driver, will be beneficial in address- will be beneficial in addressing conges- sites. Street signs with large, bold ing congestion issues. tion issues. Improved directional signs, letters, both in advance of and at route markers, large street signs, signs intersections, are extremely helpful on mast arms, etc., are all means of to motorists and can improve reducing the level of uncertainty (and traffic flow. People looking for a thus potential indecision) of drivers. particular street tend to slow down. The provision of easily read Traffic markings include all traffic cross street signs is relatively cheap lane markings (both longitudinal and and can have great benefit to transverse), symbols, words, object traffic flow, as well as improve markers, delineators, cones or other customer satisfaction. devices except signs, that are applied upon or attached to the pavement or Variable message signs can be used mounted at the side of the road to to inform drivers of regulations or guide traffic or warn of an obstruc- instructions that are applicable only tion. Traffic markings have certain during certain periods of the day or definite functions to perform in the under certain traffic conditions. The proper control of vehicular and need for, and use of, variable message pedestrian traffic. They serve to regu- signs has increased considerably over late, guide, and channel traffic into the past several years. These variable message signs, which can be changed
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM the proper position on the street or of traffic and the enhancement of the highway, and to supplement the regu safety of operation. lations or warnings of other traffic Implementation A modest planning control devices. They also serve as a effort is required to identify locations psychological barrier for opposing for implementation. A routine design streams of traffic, as a warning device and construction process is imple- for restricted sight and passing dis- mented, using appropriate design tances, and provide information for standards. There are five basic factors turning movements. As an aid to Five basic factors must be that must be employed in designing pedestrians, they channelize move- employed in designing and main- and maintaining traffic control ment into locations of safest crossing taining traffic control devices: devices: (U.S. DOT 1988) and, in effect, provide for an exten- 1. Design sion of the sidewalk across the road- Design-the combination of physical 2. Placement way. Traffic markings aid the vehicle features such as size, colors, and shape driver in many respects without needed to command attention and 3. Operation diverting attention from the roadway. convey a message. 4. Maintenance Transverse marking lines are used Placement-the installation of 5. Uniformity for crosswalks, stop lines, railroad devices so that they are within the crossings, parking space markings, lines of vision of the users, and thus word and symbol markings and curb able to command attention and allow markings. time for response. Miscellaneous traffic control Operation-the application of devices are used to guide traffic in devices so that they meet traffic and around work areas, to alert traffic requirements in a uniform and consis- to hazards that are ahead, and to tent manner, fulfill a need, command provide a means of identifying specif- respect, and allow time for response. ic locations on streets and highways. Maintenance-the upkeep of devices They include barricades, vertical pan- to retain legibility and visibility, or els, drums, barricade warning lights, the removal of devices if not needed. rumble strips and milepost markers. Uniformity-the uniform application Benefits/Costs: The costs associated of similar devices for similar situations. with planning and implementing this In addition, the effectiveness of technique are modest, and vary traffic control devices is greatly depending upon complexity and the enhanced when visible and active number installed. The benefits are enforcement of the related law substantial, because of the separation occurs.
References: Institute of Transportation Engineers. 1992., Traffic Engineering Handbook, Fourth Edition, Washington D.C. U. S. Department of Transportation. 1988 Manual on Unifm Traffic Control Detices, Federal Highway Administration, Washington D.C.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY RIALS AND LOCAL STREETS: town area. Because a contraflow lane EM MANAGEMENT is taken from the off-peak direction High Occupancy Vehicle (HOV) flow, there are usually no major phys- Facilities on Arterials ical changes required of the roadway; however, good signing is a critical Description: Similar to HOV feature. To date, all contraflow lanes priority treatments on freeways, HOV in downtown areas have been limited preferential treatment on arterials to buses due to the typically high bus provides for more effective manage- volumes and safety concerns arising ment of scarce highway space during from the contraflow movements. peak periods by moving more people in fewer vehicles. High occupancy Other Downtown HOV Treatment- vehicles include buses, vanpools and Apart from the concurrent flow and Carpools. Although a variety of HOV contraflow lanes, several other sup facilities have been used in the portive HOV treatments can be United States, there are usually one found in downtown areas, including:
or two types currently being used in l Exclusive transit streets
urban areas on major arterials: l Priority signals
(Levinson et al 1975) l Priority parking spaces HOV facilities currently being used
l Priority parking rates in urban areas on major arterials Concurrent Flow-Concurrent flow l Priority ramp access Include. HOV lanes on surface streets are the most widely applied HOV priority Benefits/Costs: If properly imple- l Concurrent Flow HOV Lanes
project, found in at least 30 mented, HOV facilities can accom- l Contraflow HOV lanes American cities. Most applications plish the following: l Other downtown HOV have occurred along curb lanes of l Induce commuters to shift to high- treatments downtown streets using a minimum er occupancy travel modes to of signing and marking. Most concur- - exclusive transit streets reduce vehicular demand in peak rent flow HOV lanes in downtown periods and consequently reduce - prionty signals areas are implemented either by traffic congestion in the short - priority parking spaces and rates taking an existing lane, moving an term, and over the long term on-street parking lane, or by narrow- - priority ramp access reduce energy consumption and air ing existing lanes to achieve an extra pollution emissions. lane. Restricted right-of-way usually prohibits the construction of an l Increase the person-carrying added lane. capacity of critically congested highway corridors to provide Contraflow Lanes-Most contraflow increased accessibility to important applications have occurred on one- major activity centers, particularly way streets, although a few projects CBDs. have applied the contraflow concept to two-way surface streets, either on . Reduce total person travel time for the opposite side of a median, or as a given levels of vehicular traffic reversible center lane. These latter demand served, i.e., optimize applications are most prevalent on transportation for people. arterial routes outside of the down-
HIGHWAYS: GETTING THE MOST OUT OF THE EXISTING SYSTEM Reduce or defer the need to con- Pittsburgh, Pennsylvania: A con- struct additional highway capacity traflow right curb bus lane was imple- for general purpose traffic thereby mented in June, 1981 along a 0.4 gaining the maximum productivity mile length of a downtown arterial. from financial resources. The lane was installed in order to carry buses diverted from a parallel Improve the efficiency and . street, which was being reconstruct- economy of public transit opera- ed. The bus lane was implemented by tions and enhance transit service removing curb parking from the arte- schedule reliability. rial, which initially had two west- Several case studies illustrate the bound lanes plus parking. After the costs and benefits that have been bus lane was implemented, there experienced in metropolitan areas. were still two remaining westbound New York City: In an effort to lanes, one of which is used for short- improve user travel times and bus term parking and loading during off reliability in Manhattan, a compre- peak hours. The bus lane was so suc- hensive HOV program for buses only cessful that it was made permanent. was developed by the New York City The bus lane carries approximately DOT Ten concurrent flow bus lanes 50 to 70 buses in the peak hour. The operating under special regulations lane is marked with overhead signs, were designated between June 1982 double yellow line delineation, and and November 1982 for a total of 11 the diamond symbol. miles. Two of the 10 bus lanes were Chicago, Illinois: Four contraflow bus entirely new. Success has been lanes were implemented during the achieved through emphasis upon a early 1980’s on streets crossing the three part approach of engineering State Street transit mall. These right treatments, enforcement strategies, curb lanes operate for seven blocks and public education programs. (0.7 mile). The bus lanes were imple- “Before and after” results revealed mented in response to severe con- that the average bus saved two to flicts between buses and right turning four minutes, representing a 15 to 25 vehicles which had occurred at virtu- percent increase in speed. Non-bus ally every bus stop in the previous traffic speeds also increased by 10 to mixed mode operation. The con- 20 percent due to the separation of traflow lanes resulted in a consolida- buses and autos. Over 3,100 buses tion of bus routes along these four and 140,000 riders utilized the lanes streets. As a result, the lanes are on 20 local and 68 express bus routes. heavily used, each averaging 120 These high volumes and time savings buses per peak period (three hours), translated into large savings in total and 50 buses per peak hour. These person-minutes for bus passengers. buses accommodate over 3,800 pas- sengers per peak period and 1,700 per peak hour on each street. Buses save from one to four minutes ( 1.4-5.7 min/mi) during peak periods with an
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY increase bus speeds of 15 to 40 per- times also improved by 0.2-0.6 min- cent. A related benefit has been utes due to the elimination of turns improved reliability of bus service and an overall decrease in volume. and greater frequency of service The specific travel time impacts of across the Loop due to the consolida- the bus lane versus those of the turn tion of bus routes. The reliability restrictions could not be isolated. improvements in the Loop also San Francisco, California - The expe- resulted in improved service along rience in San Francisco with HOV the bus routes outside of the down- lanes on downtown arterials has been town area. The combination of mixed. In particular, transit times on decreased travel time and improved city streets after conversion to HOV reliability allowed the transit operator lane have not significantly declined, to eliminate five buses without especially on those streets where decreasing service, thereby yielding traffic volumes before the conversion an annual operating cost savings of were not large. Only in those cases about $400,000. where traffic was continuously con- Houston, Texas: A concurrent right gested were there any clear benefits. curb HOV lane operates on both The Department of Parking and sides of Houston’s Main Street, a six Traffic for the City and County of lane, two-way arterial. The HOV San Francisco has demonstrated, lanes are reserved for buses only on however, that the distance between weekdays from 7a.m. to 6p.m. The bus stops, the placement of bus stops project was the first HOV treatment in relation to traffic signals and stop implemented in 1971 as a part of a signs, and improved parking and traf- Transit Action Program in Houston. fic enforcement can have direct The key feature of the downtown impacts on transit speeds (City and HOV treatment is the prohibition of County of San Francisco 1989). A all turns along the street for 11 blocks recent implementation of an HOV (0.7 mile). This restriction was lane on Market Street in the down- imposed at the same time that the town showed other types of benefits bus lanes were implemented. As a to transit operations. Of particular result, once a vehicle enters Main concern in this case was the delay Street within a restricted zone it can- caused by traffic signals to transit not turn off until it reaches the end vehicles waiting to enter boarding of the project. There are virtually no islands. By reducing the number of access points on Main Street to park- non-transit vehicles in the nearside ing lots, alleys or hotels. In addition, lane, it was hoped that all transit most off-peak truck loading is per- vehicles would be able to reach the formed on cross streets, thus eliminat- islands without significant signal ing the obstruction of the bus lanes delay. The travel time impact of during the day. Travel time savings reserving this lane for transit vehicles were evidenced for both buses and was limited, a 2 percent reduction in general traffic. Buses saved from 0.4- travel time (12 seconds). However, 2.0 minutes; general traffic travel preferential treatment did have a very
HIGHWAYS. GETTING THE MOST OUT OF THE EXISTING SYSTEM positive impact on transit vehicle . Public education (i.e., marketing) delay. Before such treatment, typical- must begin before the project is ly 12 of the 50 buses on Market implemented. The high auto, n-an Street were caught in the signal sit, and pedestrian volumes in the queue. After the treatment, none of downtown can create volatile and the buses had such delay (City and potentially confusing travel move- County of San Francisco 1997). ments which must be understood by the public. Implementation: Although every HOV treatment is unique in its l The HOV project must be clearly setting, there are several guidelines signed and marked to promote that have been common to most of understanding of and compliance the projects implemented to date. with the restrictions. These features should be explained as HOV project planning must . part of the public education. include various agencies and inter- est groups such as: l Improved travel time reliability l Traffic and efficient movement of persons l Business groups should be the primary goals in a l Enforcement downtown area. Many projects l Transit do not show a large actual travel l Political leaders time savings due to the large l Ridesharing number of buses, frequent bus l Citizen groups stops, and other traffic friction; l Taxi operators however, improved reliability has l Motorist groups been linked to ridership increases l Employers and employer and operating cost savings. associations l An HOV project should be l Environmental groups planned and implemented in the . The project must be flexible to context of other HOV treatments. meet changing conditions in the In a tightly defined downtown downtown area, including different area, a combination of HOV treat- pedestrian flows, construction ments (e.g., a network of bus lanes, activities, and transit operations. bus lane plus signal priority) can greatly enhance the effectiveness Enforcement is the key to an effec- . and visibility of the HOV concept. tive HOV treatment. Adequate Coordination with transit and enforcement must be in place ridesharing incentives should also immediately to establish the be provided. credibility of the project. l The effects of an HOV project on non-users as well as users must be analyzed. The implementation of HOV treatments on high volume
A TOOLBOX FOR ALLEVIATING TRAFFlCCONGESTION AND ENHANCING MOBILITY downtown streets can result in . HOV treatment can significantly adverse effects on non-HOV traffic alter the flow of traffic and pedes- if the project is not well-designed. trian movement on the arterial As a general rule, the traffic flow (and adjacent) streets. Therefore, a for non-users should not be study should be done that degraded more than one level- evaluates the effect on businesses of-service category (e.g., level of of such a treatment. service “C” to “W). In addition to these points, . Projects with unsolvable safety advances in intelligent transportation and/or operational problems system technology (ITS) have should be avoided. provided opportunities for improving arterial bus operations. For example, Most downtown HOV treatments . providing preemption of traffic (exclusive of transit malls) can be signals for buses in the HOV lanes implemented at a low to moderate can be done by linking the oncoming cost relative to other highway or bus to the traffic signal controller. transit changes. Concurrent flow Automated passenger information and contraflow lanes can often be systems can provide riders with real initially implemented at a low time information concerning bus cost, with additional funds for final arrivals. These innovations can great- signs and markings expended later, ly enhance the attractiveness of tran- once the project has been estab- sit service (Transportation Research lished. Thus, major initial capital Board 1995). costs can be avoided.
References: City and County of SanFran&co.1989. Transit Preferential Streets Program, May. City and County of San Francisco. 1997. “Before-and-After Study of Market Street Transit Only Lane,” Department of Parkmg and Traffic, March 27. Levinson, H., et al. 1975. Bus Use of Highways, NCHRP Report 155, Transportation Research Board, Washington D.C. Transportation Research Board. 1995. HOV Systems in a New Light, Proceedings of a National Conference on High-Occupancy Vehicle Systems, June 5-8, 1994, Transportation Research Circular 442, Washington D.C., July.
HIGHWAYS GETTING THE MOST OUT OF THE EXISTING SYSTEM Parking Management l Cities often require developers to Description: Parking management is provide too much parking. a jurisdictional approach toward the l Parking standards are usually not provision, control, regulation, or tailored to the specific use charac- restriction of parking space. Parking teristics of office buildings. management can consist of actions l Parking policy is rarely an issue of that fall into six major categories: on- political importance in suburban street parking, off-street parking, cities. fringe and corridor parking, pricing, enforcement and adjudication, and l Transit operators face a daunting marketing. The major types of action task serving low density, over- in each category are shown in Table parked employment centers. 2.5. Although discussed here, parking l Some suburban areas have pricing receives a more detailed dis- matured to the point where they cussion in Chapter 5. resemble central business districts, Parking management can be and can use urban parking man- undertaken for many reasons. In agement strategies. many cases, communities want to Parking management is a l Suburban parking policy is unlike- have a comprehensive parking pro- jurisdictional approach toward ly to change unless most of the gram that provides a sufficient stakeholders involved in parking the provision, control, regulation, amount of parking space to serve resi- supply and management are con- dential, commercial, and retail activi- or restriction of parking space. vinced that change is desirable. ties. In other situations, communities use parking policies to achieve differ- Benefits/Costs: The benefits and ent objectives, such as to improve costs of parking management actions environmental quality, encourage a depend upon the specific strategy or shift to different modes of transporta- strategies to be implemented, as well tion, or to preserve sufficient access as the objectives to be achieved [see for local residents. Importantly, park- Chapter 5 for site-specific parking ing policies are one of the most effec- strategies]. Table 2.6 shows the esti- tive actions that can be taken to mated impact of parking manage- reduce single occupant vehicle use. A ment strategies if applied to Portland, study on suburban parking, however, Oregon (Portland State University illustrates the challenges facing public 1995). Not surprisingly, parking officials who wish to use parking poli- pricing strategies have the greatest cies to meet some of these objectives. impact on single occupant vehicle This study concluded: (Willson 1992) use and transit ridership. This Table also shows an implementation Parking is substantially oversup . feasibility analysis which indicates plied at suburban office worksites. the short- and long-term conse- . Employers and/or commuters quences of these types of actions. rarely receive appropriate price signals about the cost of providing parking.
A TOOLBOX FOR ALLEVIATING TRAFFIC CONGESTION AND ENHANCING MOBILITY