1、A Guide for Achieving in Highway DesignFlexibilityAmerican Association of State Highway and Transportation OfficialsMay 2004AGuideforAchievingFlexibilityinHighwayDesignApril2004ISBN: 1-56051-259-8 Publication Code: FHD-1American Association of State Highway and Transportation Officials444 North Capi
2、tol Street, NWSuite 249Washington, DC 20001www.transportation.orgA Guide for Achieving in Highway DesignFlexibilityMay 2004 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.ISBN: 1-56051-259-8 Publication
3、 Code: FHD-12004 American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law. 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.iiiV
4、oting MembersOfficers:President: John R. Njord, UtahVice President: J. Bryan Nicol, IndianaSecretary-Treasurer: Larry M. King, PennsylvaniaRegional Representatives:REGION I: James Byrnes, Connecticut, One-Year TermAllen Biehler, Pennsylvania, Two-Year TermREGION II: Whittington W. Clement, Virginia,
5、 One-Year TermFernando Fagundo, Puerto Rico, Two-Year TermREGION III: Mark F. Wandro, Iowa, One-Year TermGloria Jeff, Michigan, Two-Year TermREGION IV: Michael W. Behrens, Texas, One-Year TermTom Norton, Colorado, Two-Year TermNonvoting MembersImmediate Past President: Dan Flowers, ArkansasAASHTO Ex
6、ecutive Director: John Horsley, Washington, DCexecutive committee20032004 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.ivJames F. Byrnes Connecticut, ChairmanRichard B. Albin Washington James O. Brewe
7、r Kansas James Ben Buchan Georgia Philip J. Clark New York Lawrence A. Durant LouisianaBrelend C. Gowan CaliforniaVicky Johnson KansasKen Kobetsky AASHTODavid L. Little Iowa Sam Masters Missouri Jim McDonnell AASHTOSeppo Sillan FHWAJay Smith MissouriTimothy L. Stark WyomingWinston Stebbins Michigan
8、James S. Thiel Wisconsinjoint task force foraesthetic design2003 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.vcontentsAcknowledgments xiIntroduction xiii1. The Project Development Process 11.1 Overvi
9、ew of the Process 11.1.1 Concept Definition 21.1.2 Planning and Alternatives Development . 21.1.3 Preliminary Design 41.1.4 Final Design and Construction 51.2 Philosophy of Geometric Highway Design 51.3 Design Criteria and Guidelines 6 1.3.1 Historical Background . 7 1.3.2 Research Basis . 81.3.3 In
10、tended Use of AASHTO Green Book . 81.3.4 Background on Design Criteria . 91.3.5 Design ExceptionsIntroduction 101.4 Highway Design Controls 121.4.1 Functional Classification 121.4.2 Terrain . 131.4.3 Location 131.4.4 Traffic Volume 131.4.5 Level of Service 151.4.6 Design Driver and Vehicle 161.5 Spe
11、edA Fundamental Input to Design 171.5.1 Selecting a Design Speed 171.5.2 Design in the Lower Speed Environment 191.5.3 Design Speed and Traffic Calming . 191.6 Project Types 201.6.1 New Construction . 201.6.2 Reconstruction of Existing Highways 211.6.3 Resurfacing, Restoration, and Rehabilitation (3
12、R) Projects . 211.7 Design Constraints 221.8 Design Decision Making . 221.9 References . 232. Context-Sensitive Solutions through Community Involvement . 252.1 Introduction 252.1.1 Identify All Stakeholders 272.1.2 Maintain Timely and Coordinated Stakeholder Input 272.1.3 Commit to an Open, Creative
13、 Approach to Problem Solving 282.2 Establishing Purpose and Need . 282.3 Conducting Project Scoping 30 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.vi2.4 Building an Effective Public Involvement Progr
14、am 302.4.1 Develop a Public Involvement Plan 302.4.2 Tailor the Public Involvement Program to Meet Specific Project and Public Needs 322.4.3 Build Community Consent through Open Communications 332.4.4 Strive for Inclusiveness 332.4.5 Maintain Continuity in the Public Involvement Program 342.4.6 Prov
15、ide and Communicate Clear, Structured Decision-Making Processes . 34 2.4.7 References for Developing an Effective Public Involvement Program 352.5 Planning and Conducting Public Meetings 352.5.1 Effective Public Notification 362.5.1.1 Project Web Sites 362.5.1.2 Reaching Nonresident Stakeholders 372
16、.5.2 Public Meeting Content and Format 382.5.2.1 Open-House Format 392.5.2.2 Formal Meeting Format 402.5.2.3 Other Meeting Formats 412.5.2.4 Visualization as a Tool for Public Meeting Communications . 412.5.2.5 Communications at the Meetings 422.5.2.6 Discussing Real Estate Issues . 432.5.2.7 Follow
17、-Up Activities After Public Meetings . 442.6 Role of the Design Professional in the Environmental Process 442.6.1 Develop Safe, Effective, Creative Alternatives . 442.6.2 Communicate Stakeholder Concerns and Issues to Decision Makers 452.6.3 Participate in the Project Decision Process . 452.6.4 Inco
18、rporate Public Input with Environmental Documents 452.6.5 Document Project Decisions 462.6.6 Assure Community Issues Are Addressed through the Construction Phase . 462.7 Effective Public Involvement is Necessary to Produce Appropriate Outcomes 472.8 References 473. Highway Geometric ElementsDesign a
19、nd Safety Considerations For Context-Sensitive Project Solutions. 493.1 Introduction 493.2 Horizontal Alignment 503.2.1 Background on the AASHTO Design Model . 513.2.2 Risk Assessment Guidelines . 523.2.3 Flexibility in the AASHTO Guidelines. 533.2.4 Mitigating Tight Curvature 543.3 Vertical Alignme
20、nt (Grades) 543.3.1 Background on AASHTO Green Book Assumptions 553.3.2 Flexibility in AASHTO Guidelines 553.3.3 Mitigating Steep Grades 553.4 Coordination of Horizontal and Vertical Alignment 563.5 Sight Distance 563.5.1 AASHTO Stopping Sight Distance (SSD) Guidelines . 563.5.1.1 Background on the
21、AASHTO Stopping Sight Distance Model 583.5.1.2 Risk Assessment Guidelines 58 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.vii3.5.1.3 Flexibility in the AASHTO Guidelines . 603.5.1.4 Mitigating Limited
22、 Stopping Sight Distance . 603.5.2 AASHTO Intersection Sight Distance (ISD) Guidelines .603.5.2.1 Background on the AASHTO Intersection Sight Distance Model 603.5.2.2 Flexibility in the AASHTO Guidelines . 613.5.2.3 Mitigating Limited Intersection Sight Distance . 613.5.3 AASHTO Passing Sight Distan
23、ce (PSD) Policy . 613.5.3.1 Background on the AASHTO Passing Sight Distance Model . 623.5.3.2 Flexibility in the AASHTO Guidelines . 623.5.3.3 Mitigating Limited Passing Sight Distance . 623.5.4 AASHTO Decision Sight Distance (DSD) Guidelines . 623.5.4.1 Background on the AASHTO Decision Sight Dista
24、nce Values 623.5.4.2 Flexibility in the AASHTO Guidelines . 633.5.4.3 Mitigating Insufficient Decision Sight Distance 633.6 Cross Section Elements . 633.6.1 Lane Width 643.6.1.1 Background on the AASHTO Lane Width Guidelines . 643.6.1.2 Flexibility in the AASHTO Guidelines . 653.6.1.3 Mitigating Nar
25、row Lanes . 653.6.2 Shoulder Width 653.6.2.1 Flexibility in the AASHTO Guidelines . 663.6.2.2 Mitigating Narrow Shoulder Widths 663.6.3 The Roadside . 673.6.3.1 Clear Zone 683.6.3.2 Roadside Elements 703.6.3.3 Roadside Design for Existing Facilities 723.6.3.4 Roadside Design in the Urban Environment
26、 . 763.6.3.5 Flexibility in the AASHTO Guidelines . 773.6.4 Medians 783.6.4.1 Medians on Rural Highways 783.6.4.2 Medians on Urban Highways . 783.6.4.3 Flexibility in the AASHTO Guidelines . 793.6.4.4 Mitigating the Effects of Narrow Medians 803.7 Bridges 803.7.1 Flexibility in the AASHTO Guidelines
27、 . 813.8 Intersections . 813.8.1 Design Vehicles Control Intersection Features 823.8.2 Flexibility in the AASHTO Guidelines 833.8.3 Mitigating Nontraditional Intersection Design Treatments . 833.9 Access Control 833.9.1 Flexibility in the AASHTO Guidelines . 843.10 Pedestrian and Bicycle Facilities
28、853.10.1 Flexibility in the AASHTO Guidelines . 863.11 Traffic Calming 873.11.1 Overview of Traffic Calming . 873.11.2 Leading a Traffic-Calming Study 88 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.v
29、iii3.11.2.1 Establish Purpose 883.11.2.2 Offer Alternatives to Traffic Calming 883.11.3 Application of Traffic-Calming Techniques . 893.11.3.1 Consider Route Diversion Effects . 903.11.3.2 Address Overall Public Safety 913.11.3.3 Implementing Traffic-Calming Plans . 913.12 Developing and Documenting
30、 Safety Sensitive Solutions 923.12.1 Overall Guidance 923.12.1.1 Avoid Combinations of Geometry Outside Typical Ranges 923.12.1.2 Maintain a Reasonable Design Speed 923.12.1.3 Mitigate the Expected Operational Effects 933.12.2 Demonstrating a Commitment to Mitigate Safety Concerns 933.12.3 Documenti
31、ng Design Exceptions . 933.13 References . 954. Legal Liability and Highway Design . 97 4.1 Introduction. 974.2 Overview of Tort Liability 974.3 Basic Principles of Tort Liability 994.4 Sovereign and Public Employee Immunity . 1014.5 Discretionary Function Immunity 1014.6 Design Immunity . 1034.7 Ab
32、sence of Decision Making . 1044.8 Design Decisions, Negligence, and the Duty of Care 1054.9 Importance of Fully Evaluating and Documenting Design Decisions 1074.9.1 Responsibility for Decision Making 1084.9.2 Risk Management . 108 4.10 What Context-Sensitive Design Practices will Reduce an Agencys E
33、xposure to Successful Claims? . 1094.11 References . 110AppendixA U.S. Federal Regulations on Environmental Protection Affecting Highway Design . 115Tables1-1 Evolution of AASHTO (AASHO) Design Policies in the United States 71-2 Guide for Selection of Design Levels of Service . 161-3 AASHTO Recommen
34、ded Ranges in Design Speeds 182-1 Resource and Other Agencies Typically Involved in Project Scoping . 312-2 Public Meeting Formats 403-1 Controlling Geometric Design Criteria . 503-2 Acceptable Shoulder Width Values for Shoulder FunctionsValues in Feet (Meters) . 673-3 Alternative Safety Mitigation
35、Measures . 94Figures1-1 Typical Project Development Process . 11-2 Public Information Meeting at which Design Alternatives Are Being Shown and Discussed . 3 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable la
36、w.ix1-3 Alternative Design Hour Volume Curves 141-4 Transit Bus May Be Appropriate Design Vehicle for Urban Intersection Design . 162-1 Web Site Page for a Highway Corridor Study 372-2 Informal, Open House Public Information Meetings Generate Effective One-on-One Discussions . 392-3 Visualizations A
37、ssist Public Understanding of Alternative Design Proposals . 412-4 Visualizations Aid Understanding of Design Complexities 423-1 AASHTO Horizontal Curve Model 513-2 Models for Stopping Sight Distance (SSD) and Parameters for Vertical Curves. 573-3 Example Stopping Sight Distance Profile 583-4 Major
38、Elements of Rural Highway Cross Sections . 633-5 Placing Utilities Underground Improves Urban Clear Zones and Corridor Aesthetics . 723-6 Special Aesthetic Barrier and Guardrail Meeting NCHRP Report 350Test Requirements 753-7 The Urban Roadside Environment Includes Pedestrians, Utility Poles, and Ot
39、her Objects Close to the Edge of Pavement . 763-8 Relationship of Access Control to Functional Classification . 843-9 Conversion of Four-Lane Roadway to Two-Lane Roadway with Center Turn Lane and Directional Bike Paths . 863-10 Speed Table in Conjunction with Pedestrian Crossing on Local Street 90 2
40、004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law. 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.xiacknowle
41、dgmentsAASHTO is indebted to the many contributors to this guide, which has been overseen through itslong evolution by the AASHTO Joint Task Force for Aesthetic Design. This joint task force was madeup of representatives from various groups within the Highway Subcommittee on Design and theStanding C
42、ommittee on Administration, including:Task Force on Environmental Design (Design)Task Force on Geometric Design (Design)Task Force for Roadside Safety (Design)Subcommittee on Legal Affairs (Administration)In addition, AASHTO wishes to thank the National Cooperative Highway Research Program(NCHRP) fo
43、r funding and staffing two research projects through the NCHRP 20-7 Program (Tasks114 and 169). The output from these projects was instrumental in the development of this guide.Finally, AASHTO wishes to thank the many individuals who provided comments and feedback dur-ing the development of this gui
44、de. 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law. 2004 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.xiiii
45、ntroductionContext-sensitive solutions (CSS) are an emerging concept in highway project planning, design,construction, and maintenance in recent years. CSS reflects the need to consider highway proj-ects as more than transportation. CSS recognizes that a transportation facility, by the way it isinte
46、grated within the community, can have far-reaching impacts (positive and negative) beyond itstraffic or transportation function. The term CSS therefore refers to an approach or process asmuch as it does to an actual design or solution. The term Flexibility in Highway Design was adopted by the Federa
47、l Highway Administration (FHWA)in their groundbreaking publication (issued in 1997) that demonstrated how agencies couldaccomplish the objects of CSS within accepted design processes and criteria. The core theme ofthe FHWA publication was flexibilityin design approaches, use of criteria, execution o
48、f designsolutions, and incorporation of special or “unique” features:This Guide Flexibility in Highway Design encourages highway designers to expand their consideration in applying the Green Book criteria. It shows that having a pro-cess that is open, includes good public involvement, and fosters cr
49、eative thinking is an essential part of achieving good design.The terms context-sensitive solutions, context-sensitive design, and flexibility in highway design areused interchangeably by some. Other terms expressing the concepts include place-sensitive designand Thinking Beyond the Pavement. These terms all refer to the same process and result: a high-way or transportation project that reflects a community consensus regarding purpose and need,with the features of the project developed to produce an overall solution that balances safety,mobility, and preservation
