A Policy on Geometric Design of Highways and Streets

The "Green Book" contains design practices in universal use as the standard for highway geometric design. In addition to being the first metric edition, it includes the following changes: Identifies the National Highway System as a new Administrative System Classification; Incorporates information from the new Highway Capacity Manual; Increases emphasis on bicycles, older persons, and the Americans with Disabilities Act; Includes adjustments to low volume road lane width and shoulder width based upon NCHRP Report 362; and Provides retaining 6.6 m (22 ft) traveled way on reconstructed highways where alignment and safety records are satisfactory. This edition supersedes the 1990 "Green Book" and its addendum, Interim Selected Metric Values for Geometric Design.