Access Management in the Vicinity of Interchanges, Volume 2: Research Overview (2022)

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2022 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 RESEARCH REPORT 977 Access Management in the Vicinity of Interchanges Volume 2: Research Overview Karen K. Dixon Eun Sug Park Maryam Shirinzad Lacy Brown Matthew Blaschke Texas A&M Transportation Institute (TTI) College Station, TX Jim L. Gattis University of Arkansas Fayetteville, AR Robert Layton Oregon State University Corvallis, OR Vergil Stover Consultant College Station, TX Phil Demosthenes Phillip B. Demosthenes, LLC Denver, CO Larry Sutherland WSP Consulting Engineers Columbus, OH Herbert Levinson Consultant New Haven, CT Subscriber Categories Highways • Design • Transportation, General 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, and implementable research is the most effective way to solve many problems facing state departments of transportation (DOTs) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transporta- tion results in increasingly complex problems of wide interest to high- way authorities. These problems are best studied through a coordinated program of cooperative research. Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 ini- tiated an objective national highway research program using modern scientific techniques—the National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation, under Agree- ment No. 693JJ31950003. The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRB’s recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive com- mittee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, univer- sities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of special- ists in highway transportation matters to bring the findings of research directly to those in a position to use them. The program is developed on the basis of research needs iden- tified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&I’s recommendations are proposed to the AASHTO Board of Direc- tors and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Academies and TRB. The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs. Published research reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet by going to https://www.mytrb.org/MyTRB/Store/default.aspx Printed in the United States of America NCHRP RESEARCH REPORT 977, VOLUME 2 Project 07-23 ISSN 2572-3766 (Print) ISSN 2572-3774 (Online) ISBN 978-0-309-67424-9 Library of Congress Control Number 2021943948 © 2022 National Academy of Sciences. All rights reserved. COPYRIGHT INFORMATION Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein. Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, FTA, GHSA, NHTSA, or TDC endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP. NOTICE The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine. The opinions and conclusions expressed or implied in this report are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors. The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names or logos appear herein solely because they are considered essential to the object of the report.

The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, non- governmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president. The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president. The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president. The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine. Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org. The Transportation Research Board is one of seven major programs of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to provide leadership in transportation improvements and innovation through trusted, timely, impartial, and evidence-based information exchange, research, and advice regarding all modes of transportation. The Board’s varied activities annually engage about 8,000 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state transportation departments, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation. Learn more about the Transportation Research Board at www.TRB.org.

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 CRP STAFF FOR NCHRP RESEARCH REPORT 977, VOLUME 2 Christopher J. Hedges, Director, Cooperative Research Programs Lori L. Sundstrom, Deputy Director, Cooperative Research Programs Waseem Dekelbab, Associate Program Manager, National Cooperative Highway Research Program Camille Crichton-Sumners, Senior Program Officer Tyler Smith, Senior Program Assistant Natalie Barnes, Director of Publications Heather DiAngelis, Associate Director of Publications NCHRP PROJECT 07-23 PANEL Field of Traffic—Area of Traffic Planning Brian K. Gage, Minnesota Department of Transportation, St. Paul, MN (Chair) Anthony J. Buczek, Oregon Metro, Portland, OR Cynthia Landez, KCI Technologies, Inc., San Antonio, TX Howard R. Ressel, New York State Department of Transportation, Rochester, NY Xiaoduan Sun, University of Louisiana, Lafayette, Lafayette, LA Brian David Toombs, Burgess and Niple, Inc., Columbus, OH Jessica Faye Upchurch, Kansas Department of Transportation, Topeka, KS Richard C. Worssam, Virginia Department of Transportation, Richmond, VA Wei Zhang, FHWA Liaison Richard A. Cunard, TRB Liaison

This report provides assistance for transportation practitioners who make decisions regarding access management in the vicinity of interchanges. It complements existing guidance but also provides additional resources, including case studies, a guide, a spread- sheet tool, and a final report. These deliverables should be of immediate use to practitioners responsible for access management and geometric design decisions. When driveways and intersections on crossroads are located too close to interchanges, operational and safety problems may occur. Access management techniques are used to balance the mobility and accessibility of through traffic with traffic entering and exiting the roadway. NCHRP Synthesis 332: Access Management on Crossroads in the Vicinity of Interchanges, published in 2004, documented and compiled the best available information on practices at the time. Since then, there have been advances in the geometric design of intersections and interchanges, and there are new resources for estimating the safety and operational impacts of access management decisions. NCHRP Synthesis 332 also identified research needed to improve interchange access management practices. Under NCHRP Project 07-23, “Access Management in the Vicinity of Interchanges,” the Texas A&M Transportation Institute was asked to review recent scholarly literature and current practices, address the research needs described in NCHRP Synthesis 332, and develop decision-making tools for practitioners’ use. Field observations and micro- simulation were used to analyze various access management features in the vicinity of interchanges. Both operational and safety performance findings are detailed in the final deliverables, which are available for immediate use by transportation agency staff who are responsible for access management decisions. In addition to this report, NCHRP Research Report 977: Access Management in the Vicinity of Interchanges, Volume 2: Research Overview, the research produced NCHRP Research Report 977: Access Management in the Vicinity of Interchanges, Volume 1: Practitioner’s Guide, the Access Management Interchange Decision Tool, and a suite of PowerPoint modules. All are available on the TRB website at trb.org by searching for “NCHRP Research Report 977.” F O R E W O R D By Camille Crichton-Sumners Staff Officer Transportation Research Board

1 Chapter 1 Background 1 Problem Statement and Research Objective 2 Research Goal 3 Report Organization 4 Chapter 2 State of Practice and Literature Review 5 Spacing Criteria 5 Spacing Scenarios for Ramp Terminal Intersections 5 Spacing Scenarios for Free-Flow, Exit Ramp Terminals 7 Spacing Criteria (Downstream) 15 Spacing Criteria (Upstream) 15 Key Influential Factors Affecting Access Spacing 16 Surrounding Land Use and Environment 16 Roadway Classification 16 Interchange Form 18 Public and Private Accesses 18 Type of Downstream Access Point 18 Downstream Storage Requirements 19 Cross Section 19 Design Speed (or Posted Speed) 19 Stopping Sight Distance 19 Decision Sight Distance 19 Volume 20 Signal Cycle Length 20 Cost and Economic Impacts 20 Level of Interchange Importance 20 Crossroad Jurisdiction 21 Safety of Access Spacing 22 Chapter 3 Data Collection 22 Site Selection 24 Site Characteristics 31 Chapter 4 Operational Analysis 31 Field Operational Study 31 Micro-Simulation Model 32 Model Development 32 Model Validation 33 Scenario Development 42 Operational Analysis Findings 42 Signalized Diamond Interchanges 46 STOP-Controlled Diamond Interchanges 47 Partial Cloverleaf Interchanges 56 Single-Point Urban Interchanges C O N T E N T S

56 Statistical Analysis of VISSIM Speed Data 60 Diamond Interchange: Signalized Intersection Without Channelized Right Turns 66 Diamond Interchange: Signalized Intersection with Channelized Right Turns 73 Diamond Interchange: STOP-Controlled Intersection 76 Partial Cloverleaf Interchange 79 Single-Point Urban Interchange 79 Summary of Results for Statistical Analysis for Speed 84 Chapter 5 Safety Analysis 84 Overview of Crash Data 88 Crash Overview Schematics and Collision Diagrams 90 Conflict Studies 90 General Observations 91 Vehicle Conflicts with Pedestrians and Bicycles 93 Distance to Adjacent (Non-Interchange) Major Intersection 94 First Access Point Downstream of the Interchange Terminal 96 First Access Point Upstream of the Interchange Terminal 99 Closely Spaced, Opposite-Side Upstream and Downstream Access Points (on Same Leg) 101 Chapter 6 Conclusions 101 Operational Performance Findings 102 Safety Performance Findings 103 Sample Guideline Language 103 Suggested Language for the AASHTO Green Book 104 Suggested Language for the TRB AMM 104 Future Research Recommendations 104 Final Comments 105 References 108 Abbreviations A-1 Appendix A Arizona (AZ) Interchanges—Site Characteristics B-1 Appendix B Arkansas (AR) Interchanges—Site Characteristics C-1 Appendix C Kansas (KS) Interchanges—Site Characteristics D-1 Appendix D Louisiana (LA) Interchanges—Site Characteristics E-1 Appendix E Minnesota (MN) Interchanges—Site Characteristics F-1 Appendix F Missouri (MO) Interchange—Site Characteristics G-1 Appendix G Texas (TX) Interchanges—Site Characteristics H-1 Appendix H Virginia (VA) Interchanges—Site Characteristics I-1 Appendix I Miscellaneous Supplemental Content J-1 Appendix J Supplemental Safety Study Using HSIS Data