Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA/TX-05/0-4740-1 4. Title and Subtitle 5. Report Date QUANTIFICATION OF INCIDENT AND NON-INCIDENT TRAVEL TIME March 2005 SAVINGS FOR BARRIER-SEPARATED HIGH-OCCUPANCY VEHICLE (HOV) LANES IN HOUSTON, TEXAS 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. David W. Fenno, Robert J. Benz, Michael J. Vickich, and LuAnn Theiss Report 0-4740-1 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Texas Transportation Institute The Texas A&M University System 11. Contract or Grant No. College Station, Texas 77843-3135 Project 0-4740 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Texas Department of Transportation Technical Report: Research and Technology Implementation Office September 2003-August 2004 P. O. Box 5080 14. Sponsoring Agency Code Austin, Texas 78763-5080 15. Supplementary Notes Project performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration. Project Title: Improved Quantification of High-Occupancy Vehicle (HOV) Lane Delay Savings URL: http//tti.tamu.edu/documents/0-4740-1.pdf 16. Abstract This project examined barrier-separated high-occupancy vehicle lane (HOV) travel time savings during incident conditions in Houston, Texas. Travel time studies, due to cost and manpower, are typically conducted infrequently and under non-incident conditions. Due to the high occurrence of incidents in large urban areas, travel time studies conducted under non-incident conditions underestimate the benefit of HOV lanes. During 2003, only an average of 17 percent of AM peak and 10 percent of PM peak periods were found to be incident free in the four HOV corridors studied: I-10 Katy, I-45 North, I-45 Gulf, and US-59 Southwest Freeways. Characteristics of the 9506 incidents reviewed from the incident database are detailed by corridor and direction, cross-section location, severity, number of vehicles, time of day, day of week, month of year, and weather conditions. A total of 341 incidents in these corridors were identified for further analysis and stratified into an incident matrix for each corridor with the extent of lane blockage versus duration of incident. Historical Automatic Vehicle Identification (AVI) data for these incident peak periods were analyzed using a Travel Time Generator software program developed in this project. This software used the AVI data to calculate segment and corridor mainlane and HOV lane travel times for 5-minute periods during the AM peak (6:00 – 9:00 AM) and PM peak periods (3:30 – 6:30 PM). Travel time savings during incident conditions were compared to non-incident conditions for the range of incidents in the matrix. The additional benefit of HOV lane travel time savings during incident conditions over non-incident travel time savings was estimated at 74 percent combining all corridors and peak periods. An important benefit of HOV lanes is shown in the travel time graphs detailing mainlane and HOV lane travel time comparisons for the range of incidents in the matrices. In comparison to average travel time savings over the entire 3-hour peak period, maximum travel time savings during incident conditions ranged up to 64 minutes in the AM peak and 49.5 minutes in the PM peak. An analysis of the entire year of 2003 AVI data (incident and non-incident conditions) estimated the benefit of HOV lanes in these four corridors during the combined AM and PM peak periods at approximately $146,000 per day or approximately $38 million per year. The Katy Freeway HOV lane showed the greatest incident and non-incident savings at nearly $80,000 per day or $20.5 million per year. 17. Key Words 18. Distribution Statement High-Occupancy Vehicle Lanes, HOV Lanes, Delay No restrictions. This document is available to the public Savings, Travel Time Savings, Incidents through NTIS: National Technical Information Service Springfield, Virginia 22161 http://www.ntis.gov 19. Security Classif.(of this report) 20. Security Classif.(of this page) 21. No. of Pages 22. Price Unclassified Unclassified 342 Form DOT F 1700.7 (8-72) Reproduction of completed page authorize QUANTIFICATION OF INCIDENT AND NON-INCIDENT TRAVEL TIME SAVINGS FOR BARRIER-SEPARATED HIGH-OCCUPANCY VEHICLE (HOV) LANES IN HOUSTON, TEXAS by David W. Fenno, P.E. Associate Research Engineer Texas Transportation Institute Robert J. Benz, P.E. Associate Research Engineer Texas Transportation Institute Michael J. Vickich Systems Analyst II Texas Transportation Institute and LuAnn Theiss Assistant Transportation Researcher Texas Transportation Institute Report 0-4740-1 Project 0-4740 Project Title: Improved Quantification of High-Occupancy Vehicle (HOV) Lane Delay Savings Performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration March 2005 TEXAS TRANSPORTATION INSTITUTE The Texas A&M University System College Station, Texas 77843-3135 DISCLAIMER The contents of this report reflect the views of the authors, who are responsible for the opinions, findings, and conclusions presented herein. The contents do not necessarily reflect the views or policies of the Federal Highway Administration (FHWA) or the Texas Department of Transportation (TxDOT). This report does not constitute a standard, specification, or regulation. This report is not intended for construction, bidding, or permit purposes. The engineer in charge of this project was David W. Fenno, P.E. #84643. v ACKNOWLEDGMENTS This project was conducted in cooperation with the Texas Department of Transportation (TxDOT). The authors wish to acknowledge the following individuals without whose insight and assistance contributed to the successful completion of this research project. • David Fink, P.E. – TxDOT Houston District, Project Director. • Terry Sams, P.E. – TxDOT Dallas District, Project Coordinator. • Clint Jumper, P.E. – TxDOT Traffic Division, Austin, member of Project Monitoring Committee. • Rajesh Gurnani, P.E. – TxDOT Dallas District, member of Project Monitoring Committee. • Lt. Vera Bumpers – Harris County Metropolitan Transit Authority, member of Project Monitoring Committee. The authors also wish to acknowledge Mike Vickich and Kathy Tran for their assistance with the development of the Travel Time Generator Software and Adam Perdue, Hanh Nguyen, Laura Sandt, and Brenda Manak from the Texas Transportation Institute (TTI) for their contributions to the report, assistance with running the Travel Time Generator, data reduction, and formatting. vi TABLE OF CONTENTS LIST OF FIGURES ....................................................................................................................... ix LIST OF TABLES.......................................................................................................................... x I. INTRODUCTION .............................................................................................................. 1 OVERVIEW AND BACKGROUND .......................................................................... 1 LITERATURE REVIEW ............................................................................................. 2 STUDY GOALS AND METHODOLOGY ................................................................. 7 II. HOUSTON FREEWAY CORRIDOR CHARACTERISTICS.......................................... 9 FREEWAY CHARACTERISTICS.............................................................................. 9 SUMMARY................................................................................................................ 13 III. CHARACTERISTICS OF HOUSTON FREEWAY INCIDENTS – 2003 ..................... 15 RIMS USAGE ............................................................................................................ 15 INCIDENTS BY CORRIDOR AND DIRECTION................................................... 16 INCIDENTS BY LOCATION ................................................................................... 18 INCIDENTS BY SEVERITY..................................................................................... 20 INCIDENTS BY NUMBER OF VEHICLES ............................................................ 20 INCIDENTS BY TIME OF DAY .............................................................................. 22 INCIDENTS BY DAY OF WEEK............................................................................. 22 INCIDENTS BY MONTH OF YEAR ....................................................................... 23 INCIDENTS BY WEATHER CONDITION ............................................................. 24 IV. HOUSTON AVI SYSTEM AND TRAVEL TIME GENERATOR SOFTWARE ANALYSIS .......................................................................................... 27 OPERATIONS ISSUES ............................................................................................. 27 MISSING DATA........................................................................................................ 28 DATA ARCHIVAL AND ANALYSIS ..................................................................... 29 TRAVEL TIME GENERATOR SOFTWARE .......................................................... 30 DEVELOPMENT OF AVI SEGMENT FACTORS.................................................. 34 V. DEVELOPMENT OF INCIDENT MATRIX .................................................................. 37 VI. SELECTON OF CANDIDATE INCIDENTS.................................................................