1. 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

2. 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)

3. Friction factors for superelevation 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 Design 2001 2004 SpeedGreen Book Green Book

4. 2001 Green Book 2004 Green Book

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

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

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

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

9. 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 http://downloads.transportation.org/Errata-GDHS-4.pdf

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