Guide for the Geometric Design of Driveways (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 659 Subscriber Categories Highways • Design • Operations and Traffic Management • Pedestrians and Bicyclists Guide for the Geometric Design of Driveways J. L. Gattis UNIVERSITY OF ARKANSAS Fayetteville, AR Jerome S. Gluck AECOM New York, NY Janet M. Barlow ACCESSIBLE DESIGN FOR THE BLIND Asheville, NC Ronald W. Eck WEST VIRGINIA UNIVERSITY Morgantown, WV William F. Hecker HECKER DESIGN, LLC Birmingham, AL Herbert S. Levinson Wallingford, CT 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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Published 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 at: http://www.national-academies.org/trb/bookstore Printed in the United States of America NCHRP REPORT 659 Project 15-35 ISSN 0077-5614 ISBN 978-0-309-15473-4 Library of Congress Control Number 2010928290 © 2010 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. 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The 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 Governing Board of the National Research Council. 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 Research Council, or the program sponsors. The Transportation Research Board of the National Academies, the National Research Council, and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the object of the report.

CRP STAFF FOR NCHRP REPORT 659 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs David B. Beal, Senior Program Officer, Retired David A. Reynaud, Senior Program Officer Megan A. Chamberlain, Senior Program Assistant Eileen P. Delaney, Director of Publications Hilary Freer, Senior Editor NCHRP PROJECT 15-35 PANEL Field of Design—Area of General Design Philip B. Demosthenes, Consultant, Denver, CO (Chair) Tom Dodds, South Carolina DOT, Columbia, SC John C. Jones, Georgetown, ME Cynthia Landez, Texas DOT, Austin, TX Rick Laughlin, HDR Engineering, Inc., Sioux Falls, SD Howard R. Ressel, New York State DOT, Rochester, NY Gary Sokolow, Florida DOT, Tallahassee, FL Richard E. Sommer, Urbana, OH Vergil G. Stover, College Station, TX Scott Windley, US Access Board, Washington, DC Joe Bared, FHWA Liaison Richard A. Cunard, TRB Liaison AUTHOR ACKNOWLEDGMENTS This guide was developed under NCHRP Project 15-35 by the Department of Civil Engineering at the University of Arkansas (UA), prime contractor, and by AECOM, subcontractor. Subcontractors to AECOM include Accessible Design for the Blind; West Virginia University; Hecker Design, LLC; and Her- bert S. Levinson. Dr. James L. Gattis, Professor of Civil Engineering at UA, was the Principal Investigator. Jerome S. Gluck of AECOM was the Co-Principal Investigator. Janet M. Barlow (Accessible Design for the Blind), Ronald W. Eck (West Virginia University), William F. Hecker (Hecker Design, LLC), and Herbert S. Levinson were special consultants for the project. 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

This report presents guidelines that will be of use to state departments of transportation, local governments, and consultants for the geometric design of driveways. It contains driveway-related terms and definitions, basic geometric controls, a summary of access spacing principles, and detailed discussions of various geometric design elements. Material related to and supporting the contents of this publication, including an extensive review of literature, can be found in NCHRP Web-Only Document 151: Geometric Design of Driveways. (This supporting document is available on the TRB website (www.trb.org), search for “NCHRP Web-Only Document 151”.) The design of driveways has benefited from little comprehensive research and no national design guidance since the American Association of State Highway Officials (AASHO) pub- lication, An Informational Guide for Preparing Private Driveway Regulations for Major High- ways, was published in 1959. Since then, roadway design, function, and volumes have changed as have vehicle design and many other aspects of the roadway environment. Driveways, especially busy commercial drives, can have a significant impact on the adja- cent roadway. Good driveway design should facilitate smooth vehicle egress and ingress to and from the roadway and should also provide for pedestrians and bicyclists. Driveway design needs to consider the roadway functional class and driveway usage to better accom- modate varying roadway environments, community needs, and existing conditions. There is currently little guidance on this issue. The Draft Guidelines for Accessible Public Rights-of-Way, disseminated by the U.S. Access Board for public comment in 2001, provides specific guidelines for such elements as mini- mum width, cross slope, grade, and edge conditions at the intersection of sidewalks and driveways to comply with the Americans with Disabilities Act. These guidelines are based on pedestrian needs and do not comprehensively address safe and efficient vehicle move- ments at driveways. Recommendations are needed to accommodate accessibility concerns as well as safe and efficient vehicle use of the driveway. This research addressed the design of driveways in the form that roadway designers use— the area where the driveway intersects the public road. The objective of this research was to develop recommendations for the geometric design of driveways that consider standard engineering practice and accessibility needs and provide for safe and efficient travel by motorists, pedestrians, and bicyclists on the affected roadway. The importance of these issues is reflected in studies that show that up to 19 percent of reported urban traffic colli- By David A. Reynaud Staff Officer Transportation Research Board F O R E W O R D

sions involve driveway traffic. This design guide was prepared by James Gattis of the Uni- versity of Arkansas and other consultants as a by-product of the research for NCHRP Proj- ect 15-35, “Geometric Design of Driveways.” This research included a literature review, a survey of street and highway departments, and field studies leading to an improved under- standing of the state of the practice. This guide presents changes to that state of practice based on the evolving requirements for driveways.

1 Chapter 1 Introduction 1 Purpose and Scope of the Guide 1 Need for This Guide 2 Organization and Structure of the Guide 3 References 4 Chapter 2 Terms and Definitions 6 References 7 Chapter 3 Design Controls 7 The Driveway Setting 8 User Mix Considerations 10 Attributes of Bicyclists, Drivers, and Pedestrians 10 Motor Vehicle Traffic Attributes 17 References 18 Chapter 4 Driveway Location and Spacing 18 General Guidelines 20 Driveway Location and Spacing 23 References 24 Chapter 5 Geometric Design Elements 26 Sight Distance and Conspicuity 29 Bicyclists 29 Pedestrians and Pedestrians with Disabilities 32 Public Transit Facilities 33 Driveway Plan and Cross-Section Elements 55 Driveway Length 65 Driveway Vertical Alignment Elements 75 Other Elements 83 References C O N T E N T S