Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. FHWA/TX-11/0-6135-1 4. Title and Subtitle 5. Report Date OPERATIONS AND SAFETY OF SUPER 2 CORRIDORS WITH February 2011 HIGHER VOLUMES Published: June 2011 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Marcus A. Brewer, Steven P. Venglar, Liang Ding, Kay Fitzpatrick, Report 0-6135-1 Byung-Jung Park 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 0-6135 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 2008–February 2011 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: Super 2 Design for Higher Traffic Volumes URL: http://tti.tamu.edu/documents/0-6135-1.pdf 16. Abstract As traffic volumes increase, in both urban and rural areas, the demand on the highway network also increases. Specifically, as rural traffic volumes rise in Texas, the pressure on the state’s network of two-lane highways rises accordingly. Previous research in Texas demonstrated that periodic passing lanes can improve operations on two-lane highways with average daily traffic (ADT) lower than 5000; these “Super 2” highways can provide many of the benefits of a four-lane alignment at a lower cost. This project expands on that research to develop design guidelines for passing lanes on two-lane highways with higher volumes, investigating the effects of volume, terrain, and heavy vehicles on traffic flow and safety. This report discusses findings from field observations and crash analysis of existing Super 2 highway corridors in Texas and computer modeling of traffic conditions on a simulated Super 2 corridor. Results indicate that passing lanes provide added benefit at higher traffic volumes, reducing crashes, delay, and percent time spent following. Empirical Bayes analysis of crash data reveals a 35 percent reduction in expected non- intersection injury crashes. Simulation results indicate that most passing activity takes place within the first mile of the passing lane, so providing additional passing lanes can offer greater benefit than providing longer passing lanes. Whether adding new passing lanes or adding length to existing lanes, the incremental benefit diminishes as additional length is provided and the highway more closely resembles a four-lane alignment. The simulation study also showed that the effects of ADT on operations were more substantial than the effects of terrain or truck percentage for the study corridor. 17. Key Words 18. Distribution Statement Super 2, Two-Lane Rural Highway, Passing Lane, No restrictions. This document is available to the Safety, Empirical Bayes, Simulation, TWOPAS, public through NTIS: IHSDM 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 208 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized OPERATIONS AND SAFETY OF SUPER 2 CORRIDORS WITH HIGHER VOLUMES by Marcus A. Brewer, P.E. Assistant Research Engineer Texas Transportation Institute Steven P. Venglar, P.E. Research Engineer Texas Transportation Institute Liang Ding, P.E. Assistant Research Engineer Texas Transportation Institute Kay Fitzpatrick, Ph.D., P.E. Senior Research Engineer Texas Transportation Institute and Byung-Jung Park, Ph.D. Former Graduate Research Assistant Texas Transportation Institute Report 0-6135-1 Project 0-6135 Project Title: Super 2 Design for Higher Traffic Volumes Performed in cooperation with the Texas Department of Transportation and the Federal Highway Administration February 2011 Published: June 2011 TEXAS TRANSPORTATION INSTITUTE The Texas A&M University System College Station, Texas 77843-3135 DISCLAIMER This research was performed by the Texas Transportation Institute (TTI) in cooperation with the Texas Department of Transportation (TxDOT) and the Federal Highway Administration (FHWA). The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official view or policies of the FHWA or 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 the project was Marcus A. Brewer, P.E. #92997. The United States Government and the State of Texas do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of this report. v ACKNOWLEDGMENTS This research was conducted in cooperation with the Texas Department of Transportation and the Federal Highway Administration. The research team gratefully acknowledges the contributions of the TxDOT Project Monitoring Committee: • Mark Wooldridge, P.E., Wharton Area Engineer and Project Director. • David Harper, P.E., Lubbock District. • Russel Lenz, P.E., Corpus Christi District/Construction Division. • Rory Meza, P.E., Design Division. • Chris Reed, P.E., Childress District. • Roy Wright, P.E., Abilene District. • Wade Odell, P.E., Research and Technology Implementation Office. • Loretta Brown, Research and Technology Implementation Office. • Frank Espinosa, Research and Technology Implementation Office. The authors also thank the following TTI staff members for their contributions to the project: • Gary Barricklow, Research Technician. • Srinivas Geedipally, Engineering Research Associate. • James Campbell, Student Worker IV. vi TABLE OF CONTENTS Page List of Figures ................................................................................................................................ x List of Tables ............................................................................................................................... xii Chapter 1 Introduction................................................................................................................. 1 Background ................................................................................................................................. 1 Purpose of the Project ................................................................................................................. 1 Organization of This Report ....................................................................................................... 2 Chapter 2 Review of Recent Literature ...................................................................................... 3 Existing Criteria .......................................................................................................................... 3 Current Practice in Texas ............................................................................................................ 5 Previous Research in Texas ........................................................................................................ 6 Traffic Volumes .......................................................................................................................... 8 Passing Lane Configuration ........................................................................................................ 9 Passing Lane Length ................................................................................................................. 12 Evaluation of Effectiveness ...................................................................................................... 13 Existing Guidance on Evaluating Super 2 Performance ....................................................... 13 Measures of Effectiveness .................................................................................................... 13 Chapter 3 Practices in Other States ......................................................................................... 17 Summary ................................................................................................................................... 17 Arizona ...................................................................................................................................... 19 California .................................................................................................................................. 20 Colorado .................................................................................................................................... 20 Connecticut ............................................................................................................................... 21 Florida ....................................................................................................................................... 22 Idaho ......................................................................................................................................... 22 Illinois ....................................................................................................................................... 27 Kansas ......................................................................................................................................