1、 Guidelines for Geometric Design of Very LOW-VO1um-e Local Roads (ADT S 400) American Association of State Highway and Tra ns po r ta t i o n Off i ci als 444 North Capitol St., N.W., Suite 249 Washington, DC 20001 (202) 624-5800 www.transportation.org Copyright 2001. by the American Association of
2、State Highway and Transportation Officials. All Rights Reserved. This book. or parts thereof, may not be reproduced in any form without written permission of the publisher. Printed in the United States of America. ISBN: 1-56051-166-4 ii American Association of State Highway and Transportation Offici
3、als Executive Committee 2001 -2002 President: E. Dean Carlson, Kansas Vice President: Brad Mallory, Pennsylvania Secretatyflreasurer: Larry King, Pennsylvania AASHTO Executive Director: John C. Hursley, Washington, D.C. Regional Representatives Region I: William Ankner, Rhode Island Joseph Boardman,
4、 New York Region II: W. Lyndo Tippett, North Carolina Bruce Saltsman. Tennessee Region III: J. Bryan Nicol, Indiana Kirk Brown, Illinois Region IV: Pete Rahn. New Mexico Joseph Perkins, Alaska . 111 Task Force on Geometric Design 2001 Terry L. Abbott Reza Amini Don T. Arkie Ray Ballentine Harold E.
5、Bastin Paul Bercich James O. Brewer Jerry Champa Philip J. Clark Susan Davis Alan Glenn Charles A. Goessel Dennis A. Grylicki Irving Harris David Hutchison Jeff Jones Wayne Kinder John LaPlante Ken Lazar Donald A. Lyford Mark A. Marek Terry H. Otterness Steven R. Oxoby Robert P. Parisi Randy Peters
6、John Pickering William A. Prosser Norman H. Roush Joe Ruffer John Sacksteder Larry Sutherland Karla Sutliff Charlie V. Trujillo Robert L. Waiters Ted Watson Members California Oklahoma Alabama Mississippi National League of Cities Wyoming Kansas California New York Oklahoma California New Jersey Nat
7、ional Association of County Engineers Mississippi National League of Cities Tennessee Nevada American Public Works Association Illinois New Hampshire Texas Arizona Nevada Port Authority of New York and New Jersey Nebras ka Mississippi FHWA, Secretary West Virginia National League of Cities Kentucky
8、Ohio California New Mexico Arkansas, Chairman Nebraska 1999 - 2000 2001 - Present 1991 -Present 1997 - 1999 1993 - 1999 1995 - Present 1986 - Present 1992 - Present 1997 - 1999 1994 - 1995 1992 - 1997 1986 - Present 1992 - 1999 1992 - 1997 1999 - Present 2001 - Present 2001 - Present 1989 - Present
9、1992 - Present 1986 - Present 1990 - 2000 1997 - 2001 1993 - 2001 1992 - 2001 1993 - 1998 1999 - Present 1995 - Present 1979 - Present 1999 - Present 1991 -Present 2001 - Present 1998 - Present 1982 - Present 1998 - Present 1991 - 2000 iv AASHTO Highway Subcommittee on Design 2001-2002 Dr. Kam K. Mo
10、vassaghi, LOUISIANA, Chair Susan Martinovich, NEVADA, Vice-Chair Dwight A. Horne, FHWA, Secretary Ken Kobetsky, P.E. and Jim McDonnell, P.E., AASHTO, Staff Liaisons - ALABAMA- Arkle, Don T. CMef, Design Bureau Alabama Department of Transportation 1409 Coliseum Boulevard Montgomery, AL 36130-3050 Ass
11、istant Chief Design Engineer Alabama Department of Transportation 1409 Coliseum Boulevard Montgomery, AL 36130-3050 Chief of Design A Policy on Arterial Highways in Urban Areas, 1957; A Policy on Design of Urban Highways and Arterial Streets, 1973; Geometric Design Standards for Highways Other Than
12、Freeways, 1969; A Policy on Geometric Design of Highways and Streets, 1984, 1990, 1994, and 2001; A Policy on Design Standards-Interstate System, 1956, 1967, and 1991; and a number of other AASHO and AASHTO policy and “guide” publications. An AASHTO publication is typically developed through the fol
13、lowing steps: (1) The Committee selects subjects and broad outlines of material to be covered. (2) The appropriate subcommittee and its task forces, in this case, the Subcommittee on Design and its Task Force on Geometric Design, assemble and analyze relevant data and prepare a tentative draft. Work
14、ing meetings are held and revised drafts are prepared, as necessary, and reviewed by the Subcommittee, until agreement is reached. (3) The manuscript is then submitted for approval by the Standing Committee on Highways. Standards and policies must be adopted by a two-thirds vote by the Member Depart
15、ments before publication. During the developmental process, comments are sought and considered from all the states, the Federal Highway Administration, and representatives of the American Public Works Association, the National Association of County Engineers, the National League of Cities, and other
16、 interested parties. xi Table of Contents Preface xi List of Exhibits . xix Foreword . xxi CHAPTER TITLES Chapter 1 Introduction 1 Chapter 2 Framework for Design Guidelines . 5 Chapter 3 Design Philosophy 11 Chapter 4 Design Guidelines 17 Chapter 5 Design Examples 53 Chapter 1 INTRODUCTION Page Defi
17、nition of Very Low-Volume Local Roads 1 Scope of Guidelines . 2 Relationship to Other AASHTO Policies 3 Organization of This Document 3 Chapter 2 FRAMEWORK FOR DESIGN GUIDELINES Area Type 5 Functional Classification . 5 Rural Major Access Roads 6 Rural Minor Access Roads . 6 Rural IndustriaVCommerci
18、al Access Roads . 7 Rural Agricultural Access Roads 7 Rural Recreational and Scenic Roads . 7 Rural Resource Recovery Roads 8 Urban Major Access Streets 8 Urban Residential Streets 8 Urban IndustriaKommercial Access Streets . 8 Other Urban Facilities . 9 Roads that Meet the Definition of More than O
19、ne Functional Subclass . 9 Traffic Volumes . 9 Design SpeedOperating Speed . 9 . XI11 Chapter 3 DESIGN PHILOSOPHY Unique Characteristics of Very Low-Volume Local Roads 11 Basis for Design Recommendations 11 Expected Systemwide Safety Effects 15 Guidelines for New Construction Versus Improvement of E
20、xisting Roads 15 Development of Design Guidelines through Risk Assessment . 13 Risk Assessment Approach . 13 Design Flexibility 16 Chapter 4 DESIGN GUIDELINES Cross Section . 17 New Construction . 17 Very Low-Volume Local Roads in Rural Areas 17 Existing Roads 20 New Construction . 20 Existing Bridg
21、es 21 Horizontal Alignment 21 New Construction . 24 Rural Major Access. Minor Access. and Recreational and Scenic Roads (250 Vehicles per Day or Less) 25 Rural Major Access. Minor Access. and Recreational and Scenic Roads (250 to 400 Vehicles per Day) 26 Rural IndustriaCommercial Access. Agricultura
22、l Access. and Resource Recovery Roads 27 Urban Major Access Streets (250 Vehicles per Day or Less) and Urban Residential Streets . 28 Urban Major Access Streets (250 to 400 Vehicles per Day) 29 Urban Industrial/Commercial Access Streets . 29 Superelevation and Superelevation Transitions 29 New Const
23、ruction . 32 Very Low-Volume Local Roads in Urban Areas . 19 Bridge Width . 20 Existing Roads 30 Stopping Sight Distance 30 Sight Distance on Horizontal Curves . 33 Sight Distance on Vertical Curves 33 Crest Vertical Curves 37 Sag Vertical Curves 38 Existing Roads 38 Intersection Sight Distance 40 G
24、eneral Considerations . 40 Clear Sight Triangles 41 xiv Approach Sight Triangles . 41 Departure Sight Triangles . 43 Identification of Sight Obstructions within Clear Sight Triangles . 43 New Construction . 44 Intersections with No Control (Case A) . 44 Intersections with Stop Control on the Minor R
25、oad (Case B) 46 Intersections with Yield Control on the Minor Road (Case C) 47 Existing Roads 47 Roadside Design 47 New Construction . 48 Clear Zone Width . 48 Traffic Barriers . 49 Existing Roads 49 Unpaved Roads 50 Two-way Single-Lane Roads . 52 Chapter 5 DESIGN EXAMPLES Example 1 53 Cross Section
26、 54 Maximum Friction Factor and Minimum Radius . 54 Horizon tal Alignment . 54 Superelevation 54 Superelevation Transition . 55 Stopping Sight Distance 55 Design Sight Distance 55 Crest Vertical Curves . 55 Sag Vertical Curves 55 Horizontal Curves . 55 Intersection Sight Distance . 55 Clear Zone Wid
27、th . 56 Traffic Barriers . 56 Roadside Design . 56 Other Design Features 56 Example 2 56 Stopping Sight Distance 57 Intersection Sight Distance . 58 Roadside Design . 58 Cross Section 58 Stopping Sight Distance 59 Cross Section 57 Horizontal Alignment . 57 Example 3 58 Horizontal Alignment . 59 Inte
28、rsection Sight Distance . 59 Roadside Design . 59 Example 4 59 Cross Section 60 Horizontal Alignment . 60 Maximum Friction Factor and Minimum Radius . 60 Superelevation 61 Superelevation Transition . 61 Stopping Sight Distance 61 Design Sight Distance 61 Crest Vertical Curves 61 Sag Vertical Curves
29、61 Horizontal Curves . 61 Intersection Sight Distance . 62 Approach Sight Triangles . 62 Departure Sight Triangle 62 Roadside Design . 62 Clear Zone Width . 62 Traffic Barriers . 62 Other Design Features . 62 Example 5 63 Cross Section 63 Horizontal Alignment . 63 Maximum Friction Factor and Minimum
30、 Radius . 63 Stopping Sight Distance 64 Intersection Sight Distance . 64 Roadside Design . 64 Example 6 64 Cross Section 65 Horizontal Alignment . 65 Stopping Sight Distance 65 Design Sight Distance 65 Crest Vertical Curves 65 Sag Vertical Curves 65 Horizontal Curves . 65 Intersection Sight Distance
31、 . 66 Roadside Design . 66 Clear Zone Width . 66 Traffic Barriers . 66 Other Design Features 66 Example 7 66 Cross Section 67 Horizontal Alignment . 67 Maximum Friction Factor and Minimum Radius . 67 Superelevation 68 Superelevation Transition . 68 Stopping Sight Distance 68 xvi Design Sight Distanc
32、e 68 Crest Vertical Curves . 68 Sag Vertical Curves 68 Horizontal Curves 69 Roadside Design . 69 Traffic Barriers . 69 Other Design Features 69 Example 8 69 . Intersection Sight Distance . 69 Clear Zone Width . 69 Cross Section 70 Horizontal Alignment . 70 Maximum Friction Factor and Minimum Radius
33、. 70 Stopping Sight Distance 71 Intersection Sight Distance . 71 Roadside Design . 71 References . 72 2 xvii xviii LIST OF EXHIBITS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. Guidelines for Total Roadway Width for New Construction of Very Low-Volume Local Roads in Rural Areas . 18 Gu
34、idelines for Total Roadway Width for New Construction of Urban Residential Streets . 20 Maximum Side Friction Factor and Minimum Radius for Horizontal Maximum Side Friction Factor and Minimum Radius for Horizontal Curves on Higher Volume Low-Speed Urban Streets . 24 Guidelines for Maximum Side Frict
35、ion Factor and Minimum Radius Guidelines for Maximum Side Friction Factor and Minimum Radius (New Construction, ADT from 250 to 400 veldday, Limited Heavy Vehicle Traffic) . 27 Guidelines for Maximum Side Friction Factor and Minimum Radius (New Construction, ADT I 400 veldday, Substantial Proportion
36、s of Heavy Vehicle Traffic) . 28 Design Sight Distance Guidelines for New Construction of Very Low-Volume Local Roads . 34 Horizontal Curve Showing Sight Distance Along the Curve and the Middle Ordinate that Defines the Maximum Unobstructed Width 35 Design Guidelines for Sight Distance on Horizontal
37、 Curves for New Construction of Very Low-Volume Local Roads . 36 Types of Vertical Curves . 37 Guidelines for Minimum Rate of Vertical Curvature to Provide Design Stopping Sight Distance on Crest Vertical Curves for New Construction of Very Low-Volume Local Roads . 39 Clear Sight Triangles for Inter
38、section Approaches 42 Recommended Sight Distance Guidelines for New Construction of Intersections with No Traffic Control (Case A) 45 Recommended Sight Distance Guidelines for New Construction of Intersections with No Traffic Control (Case A) 46 Guidelines for Minimum Radius of Curvature for New Con
39、struction of Unpaved Surfaces with No Superelevation . 5 1 Traction Coefficients Used in Design of Horizontal Alignment on Unpaved Roads . 5 1 Curve Design on Higher Volume Roadways . 23 (New Construction, ADT 250 vehday, Limited Heavy Vehicle Traffic) 26 xix Foreword As highway designers, highway e
40、ngineers strive to provide for the needs of highway users while maintaining the integrity of the environment. Unique combinations of design requirements that are often conflicting result in unique solutions to the design problems. The geometric design of very low-volume local roads presents a unique
41、 challenge because the very low traffic volumes and reduced frequency of crashes make designs normally applied on higher volume roads less cost effective. The guidance supplied by this text, Geometric Design Guidelines for Very Low-Volume Local Roads (ADTI400), addresses the unique needs of such roa
42、ds and the geometric designs appropriate to meet those needs. These guidelines may be used in lieu of the guidance in A Policy on Geometric Design of Highways and Streets, also known as the Green Book The guidance presented here will be incorporated in a future edition of that policy. The guidelines
43、 for geometric design of very low-volume local roads are the result of a research and development process initiated by AASHTO in 1996. These guidelines were initially developed through two projects of the National Cooperative Highway Research Program (NCHRP), which is jointly sponsored by AASHTO and
44、 MA. After completion of the NCHRP research, these guidelines went through the normal AASHTO review process. During the development process, representatives of other interested organizations such as the National Association of County Engineers, the American Society of Civil Engineers, the U.S. Fores
45、t Service, the American Public Works Association, and the National League of Cities have participated in review of the guidelines. Design values are presented in this document in both metric and U.S. customary units and were developed independently within each system. The relationship between the me
46、tric and U.S. customary values is neither an exact (soft) conversion nor a completely rationalized (hard) conversion. The metric values are those that would have been used had the policy been presented exclusively in metric units; the U.S. customary values are those that would have been used if the
47、policy had been presented exclusively in U.S. customary units. Therefore, the user is advised to work entirely in one system and not attempt to convert directly between the two. The fact that new design values are presented herein does not imply that existing streets and highways are unsafe, nor doe
48、s it mandate the initiation of improvement projects. A Policy on Geometric Design of Highways and Streets states that specific site investigations and crash history analysis often indicate that the existing design features are performing in a satisfactory manner. The cost of full reconstruction for
49、these facilities, particularly where major realignment is not needed, will often not be justified. This is especially true for very low-volume roads which experience substantially fewer crashes than higher volume roads. These guidelines recommend an approach to geometric design for very low-volume roads, including both new construction and projects on existing roads, that is based on research concerning the safety cost-effectiveness of geometric elements and on reviews of site-specific safety conditions. These guidelines address issues for which approp
