A Policy on Geometric Design of Highways and Streets, 5th Edition
This fifth edition of AASHTO's "Green Book" contains the latest design practices in universal use as the standard for highway geometric design and has been updated to reflect the latest research on superelevation and side friction factors as presented in NCHRP Report 439. New exhibits in Chapter 3 will help designers to quickly and accurately determine the side friction factor used for horizontal curve design, the superelevation rates for various curve radii, and the minimum radii with normal crown for each of the five maximum superelevation rates. The book features:
- 418 Exhibits, tables, and drawings;
- Dual units (metric and U.S. customary) throughout;
- Larger format to provide easy-to-read text and graphics;
- Compliance with the Americans with Disabilities Act;
- Discusses the new AASHTO Bicycle Guide and AASHTO Pedestrian Guide;
- Incorporates research from NCHRP Reports 375, 383, 400, 420, and 439.
Chapter 1: Highway Functions
Functional Classification, Functional System Characteristics, Functional Highway Systems in Urbanized Areas.
Chapter 2: Design and Controls Criteria
Design Vehicles, Driver Performance, Highway Capacity, Access Control and Management, The Pedestrian, Bicycle Facilities, Safety, Environment, Economic Analysis.
Chapter 3: Elements of Design
Sight Distance, Horizontal Alignment, Vertical Alignment.
Chapter 4: Cross Sections Elements
Pavement, Lane Widths, Shoulders, Horizontal Clearance to Obstructions, Curbs, Drainage Channels and Side Slopes, Illustrative Outer Cross Sections, Traffic Barriers, Medians, Frontage Roads, Outer Separations, Noise Control, Roadside Control, Tunnels, Pedestrian Facilities, Bus Turnouts, On-Street Parking.
Chapter 5: Local Roads and Streets
Local Rural Roads, Local Urban Streets, Special Purpose Roads.
Chapter 6: Collector Roads and Streets
Rural Collectors, Urban Collectors.
Chapter 7: Rural and Urban Arterials
Rural Arterials, Urban Arterials: General Design Characteristics, Access Management, Bikeways and Pedestrian Facilities Operation Control and Regulations, Provisions for Utilities, Public Transit Facilities.
Chapter 8: Freeways
General Design Considerations, Rural Freeways, Urban Freeways, Elevated Freeways, Ground Level Freeways.
Chapter 9: Intersections
General Design Considerations and Objections, Capacity Analysis, Alignment and Profile, Islands, Turning Roadways with Corner Islands, Free-Flowing Turning Roadways at Intersections, Superelevation for Turning Roadways at Intersections; Traffic Control Devices, Intersection Sight Distance.
Chapter 10: Grade Separations and Interchanges
Introduction and General Types of Interchanges, Warrants for Interchanges and Grade Separations, Adaptability of Highway Grade Separations and other Interchange Design Features.
From the Foreword
As highway designers, highway engineers 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 guidance supplied by this text, A Policy on Geometric Design of Highways and Streets, is based on established practices and is supplemented by recent research. The text is also intended to form a comprehensive reference manual for assistance in administrative, planning, and educational efforts pertaining to design formulation.
Design values are presented in this document in both metric and US customary units and were developed independently within each system. The relationship between metric and US 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 US customary values are those that would have been used if the policy had been presented exclusively in US customary units. Therefore, the user is advised to work entirely in one system and not attempt to convert directly between the two.
Emphasis has been placed on the joint use of transportation corridors by pedestrians, cyclists and public transit vehicles. Designers should recognize the implications of this sharing of the transportation corridors and are encouraged to consider not only vehicular movement, but also movement of people, distribution of goods, and provision of essential services. A more comprehensive transportation program is thereby emphasized.
Cost-effective design is also emphasized. The traditional procedure of comparing highway-user benefits with costs has been expanded to reflect the needs of nonusers and the environment. Although adding complexity to the analysis, this broader approach also takes into account both the need for a given project and the relative priorities among various projects. The results of this approach may need to be modified to meet the needs-versus-funds problems that highway administrators face. The goal of cost-effective design is not merely to give priority to the most beneficial individual projects but to provide the most benefits to the highway system of which each project is a part.
Most of the technical material that follows is detailed or descriptive design information. Design guidelines are included for freeways, arterials, collectors, and local roads, in both urban and rural locations, paralleling the functional classification used in highway planning. The book is organized into functional chapters to stress the relationship between highway design and highway function. An explanation of functional classification is included in Chapter 1. |
