Median Intersection Design for Rural High-Speed Divided Highways (2010)

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TRANSPORTAT ION RESEARCH BOARD WASHINGTON, D.C. 2010 www.TRB.org N A T I O N A L C O O P E R A T I V E H I G H W A Y R E S E A R C H P R O G R A M NCHRP REPORT 650 Subscriber Categories Highways • Design • Safety and Human Factors Median Intersection Design for Rural High-Speed Divided Highways T.H. Maze Joshua L. Hochstein Reginald R. Souleyrette INSTITUTE FOR TRANSPORTATION AT IOWA STATE UNIVERSITY CENTER FOR TRANSPORTATION RESEARCH & EDUCATION Ames, IA A N D Howard Preston Richard Storm CH2M HILL Mendota Heights, MN Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. 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CRP STAFF FOR NCHRP REPORT 650 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs B. Ray Derr, Senior Program Officer Emily R. Greenwood, Senior Program Assistant Eileen P. Delaney, Director of Publications Andréa Briere, Editor NCHRP PROJECT 15-30 PANEL Field of Design—Area of General Design Thomas M. Welch, Iowa DOT, Ames, IA (Chair) Don T. Arkle, Alabama DOT, Montgomery, AL Drew Boyce, Delaware DOT, Dover, DE Rene Garcia, Texas DOT, Austin, TX James L. Gattis, II, University of Arkansas - Fayetteville, Fayetteville, AR Michael D. Hurtt, Clough Harbour & Associates LLP, Albany, NY Rodney D. Lacy, Kansas DOT, Topeka, KS Richard D. “Dick” Powers, Herndon, VA James D. Young, Ohio DOT, Columbus, OH Karl H. Zimmerman, Valparaiso University, Valparaiso, IN Martin W. “Marty” Hargrave, FHWA Liaison Richard A. Cunard, TRB Liaison C O O P E R A T I V E R E S E A R C H P R O G R A M S AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 15-30 by the Center for Trans- portation Research and Education (CTRE) at Iowa State University (ISU) and CH2M HILL. CTRE was the contractor for this study, with CH2M HILL serving as a subcontractor. Dr. Tom H. Maze, Professor of Civil Engineering at ISU, was the Principal Investigator of this research. The other authors of this report include Joshua L. Hochstein, Graduate Research Assistant and Ph.D. Candidate at ISU; Howard Preston, Senior Transportation Engineer at CH2M HILL; Richard Storm, Transportation Engineer at CH2M HILL; and Dr. Reginald R. Souleyrette, Gerald and Audrey Olson Pro- fessor of Civil Engineering at ISU. The authors would like to thank the following individuals for providing crash data and other relevant information related to the case studies presented in Chapter 4: Michael Pawlovich, Iowa DOT, Traffic Safety/Crash Data Engineer; David Little, Iowa DOT District 2, Assistant District Engineer; Peter Tollenaere, Iowa DOT District 5, Assistant District Engineer; Eldon Rossow, City of Fort Dodge, Iowa, City Engineer; Robert Kiel, Maryland SHA, Assistant District Engineer–Traffic; Larry Gredlein, Maryland SHA, Trans- portation Engineer–District 2; Ray Starr, Minnesota DOT, Assistant State Traffic Engineer; Mike Weiss, Minnesota DOT, State Signing Engineer; Max Donath, University of Minnesota, ITS Institute Director; Brian Chandler, Missouri DOT, Traffic Safety Engineer; Dave Peterson, Nebraska Department of Roads, Traffic Engineer; Shawn Troy, North Carolina DOT, Safety Evaluation Engineer; Carrie Simpson, North Carolina DOT, Traffic Safety Project Engineer; and Edward Fischer, Oregon DOT, State Traffic Engineer.

This report describes common safety issues at median intersections on rural divided highways and presents innovative geometric and operational treatments for addressing those issues. Ten case studies illustrate how they have been applied in the field. The report includes recommendations for modifications to the AASHTO A Policy on Geometric Design of Highways and Streets (Green Book) and the Manual on Uniform Traffic Control Devices (MUTCD). Rural high-speed divided highways are a blend of design elements from two-lane high- ways and controlled-access freeways. This allows them to perform better than two-lane highways while costing less than a freeway. This blend does, however, make it difficult to find specific guidance for their design and operation. On a divided highway, crashes cluster at the intersections and several transportation agencies have tried innovative treatments to reduce the crash frequency and severity. Many of these treatments are relatively new and have only been installed at a few sites. This makes it difficult to develop solid statistics on their effectiveness in improving safety. In NCHRP Project 15-30, Iowa State University and CH2M Hill summarized the Green Book and MUTCD material relevant to designing and operating rural divided highways. They then analyzed causal factors for common types of crashes at divided highway intersec- tions and identified effective treatments for improving safety at the intersections by review- ing the literature and contacting transportation agencies. A workshop was held to build upon these efforts. In preparing this report, they documented 10 case studies to illustrate how these treatments can be applied in the field. This report will be useful to designers and safety engineers responsible for rural high- speed divided highways. Those readers are sure to find new ideas that could be beneficially applied to their highways. The report recommends that the performance of new deployments be documented so that future efforts can better quantify the effects of these treatments. F O R E W O R D By B. Ray Derr Staff Officer Transportation Research Board

C O N T E N T S 1 Summary 4 Chapter 1 Introduction and Research Approach 4 Background 5 Problem Statement 13 Research Objectives 14 Research Approach and Report Organization 16 Chapter 2 Current Design Guidance Review, Limitations, and Recommendations 16 Overview 16 Green Book Review 25 MUTCD Review 42 Green Book and MUTCD Recommended Revisions Summary 44 Chapter 3 Rural Expressway Intersection Safety Literature Review 44 Overview 44 Safety Effects of Expressway Intersection Features 44 Rural Expressway Intersection Safety Treatments 64 Chapter 4 Case Studies of Selected Rural Expressway Intersection Safety Treatments 64 Overview 64 J-Turn Intersection Case Study 84 Offset T-Intersection Case Study 91 Jughandle Intersection Case Study 98 Intersection Decision Support Technology Case Study 103 Static Roadside Markers Case Study 106 Left-Turn Median Acceleration Lanes Case Study 112 Offset Right-Turn Lanes Case Study 123 Offset Left-Turn Lanes Case Study 135 Freeway-Style Advance Intersection Guide Signing Case Study 140 Dynamic Advance Intersection Warning System Case Study 147 Chapter 5 Conclusions, Recommendations, and Future Research Needs 147 Conclusions 147 Recommendations 150 Future Research Needs 152 References 156 Abbreviations and Acronyms 158 Appendices