New AASHTO Design Publications

16 Pages·2011·1.37 MB·English

New AASHTO Design
Publications
2005
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
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
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)
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
2004 Green Book

2001 Green Book
Superelevation table from 2001 Green Book
Exhibit 3-23. Values for Design Elements Related to
Design Speed and Horizontal Curvature (e = 8%)
max
Superelevation table from 2004 Green Book
Exhibit 3-27. Minimum Radii for Design Superelevation Rates,
Design Speeds, and e = 8%
max
Middle Ordinate of Horizontal Curve -- 2001
Exhibit 3-58. Diagram Illustrating Components for
Determining Horizontal Sight Distance.
Middle Ordinate of Horizontal Curve -- 2004
HSO = Horizontal
Sightline Offset
Exhibit 3-54. Diagram Illustrating Components for
Determining Horizontal Sight Distance.