New AASHTO Design Publications 2005

1. New AASHTO Design Publications2005

2. New AASHTO Design Publications • A Policy on Geometric Design of Highways and Streets (2004 Green Book) • A Policy on Design Standards – Interstate System • Guide for High-Occupancy Vehicle Facilities • Guide for Park-and-Ride Facilities • Guide for the Planning, Design, and Operation of Pedestrian Facilities

3. 2004 Green Book • Changes include: • Superelevation • M – Middle ordinate of horizontal curve • Technical Corrections Green Book + Interstate Standards constitute basic design standards for NHS adopted by FHWA

4. Superelevation revisions include: • Reworded and rearranged topics • Friction factors revised from three separate curves to one curve, minor changes to values for low speed • Reformatted superelevation tables, minor changes to values for low speed design • Length of superelevation runoff moved to separate table • New table for low speed urban streets (superelevation optional)

5. Friction factors for superelevation Design 2001 2004 Speed Green Book Green Book 15 0.175 0.32 20 0.170 0.27 25 0.165 0.23 30 0.160 0.20 35 0.155 0.18 40 0.150 0.16 45 0.145 0.15 > 50 Same

6. 2004 Green Book 2001 Green Book

7. Superelevation table from 2001 Green Book Exhibit 3-23. Values for Design Elements Related to Design Speed and Horizontal Curvature (emax = 8%)

8. Superelevation table from 2004 Green Book Exhibit 3-27. Minimum Radii for Design Superelevation Rates, Design Speeds, and emax = 8%

9. Middle Ordinate of Horizontal Curve -- 2001 Exhibit 3-58. Diagram Illustrating Components for Determining Horizontal Sight Distance.

10. Middle Ordinate of Horizontal Curve -- 2004 HSO = Horizontal Sightline Offset Exhibit 3-54. Diagram Illustrating Components for Determining Horizontal Sight Distance.

11. Technical Corrections • Page 145, Replaced 8 values in Exhibit 3-14 (Minimum radii for horizontal curves) • Page 589, Replaced 6 values in Exhibit 9-19 (Design for turns at intersections) • Page 838, Replaced Exhibit 10-60 (Typical gore details for exit terminals) • Page 843, Replaced column heading in Exhibit 10-67 (Design widths for turning roadways) • Corrected typos • Corrected incorrect exhibit references Errata listings for previous editions: http://downloads.transportation.org/Errata-GDHS-4.pdf

12. States are therefore allowed to use either the 2001 or 2004 Green Book as the design standard for projects on the NHS.

13. Replaces 1991 Policy • FHWA will formally adopt through Federal Register process • Added metric values • Design speed for rolling terrain eliminated, now same as level terrain • Revised shoulder width discussion for mountainous terrain • Sloping curbs, when allowed outside shoulder, limited to 4-inch height A Policy on Design Standards – Interstate System

14. HOV Guide • Replaces 1992 Guide • Rewritten and expanded guidance for HOV • Includes planning, design, operation and enforcement • Separate chapters for freeways and arterial streets • Can also be used for HOT lanes or managed lanes

15. Park-and-Ride Guide • Replaces 1992 Guide • Rewritten and expanded to cover all elements of the development process • Defining the type and purpose of the facility • Includes planning, operations, and design • Architecture, landscape, and art

16. Pedestrian Guide • New publication • Purpose is to provide guidance for accommodating pedestrian facilities • Scope includes planning, design, and operations • Includes information about accessibility laws and regulations