States' Use of Geometric Design Standards
RCED-95-243: Published: Sep 19, 1995. Publicly Released: Sep 19, 1995.
- Full Report:
Pursuant to a congressional request, GAO reviewed: (1) the design standards states use or plan to use to improve and reconstruct roads in scenic areas; and (2) what national design standards or guidance is available to states for improving and reconstructing such roads.
GAO found that: (1) twenty-four of the 29 states surveyed use the American Association of State Highway and Transportation Officials' guidance (green book) as their standard for improving or reconstructing their scenic byways; (2) the green book affords enough flexibility to preserve scenic resources while meeting the states' needs for mobility; (3) states rely on the green book because they are concerned that they may be sued for a deficient design if an accident occurs on a road that has been designed using an alternative design standard; (4) the remaining five states have developed or are planning to develop their own standards to avoid having to take design exceptions; (5) there are other sources available to states concerning the national guidance standards on geometric design, including the National Park Service's (NPS) Park Road Standards and the Transportation Research Board's (TRB) criteria for resurfacing, restoring, and rehabilitating roadways, which is referred to as the 3R criteria; (6) NPS standards give higher priority to scenic preservation, while the 3R criteria emphasize preserving the existing roadway; and (7) the issues in selecting the appropriate design standard for a scenic byway depends on the primary purpose of the road.