Citation

Wright PH, Robertson LS. Transp. Res. Rec. 1976; 609: 1-8.

Copyright

(Copyright © 1976, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

This paper presents a survey of road curvature, superelevation, gradient, and number and distance from the roadway of roadside hazards conducted in Georgia at 300 sites of fatal crashes into fixed objects and at 300 comparison sites 1.6 km (1 mile) from the accident site. More than 26 percent of fatal crash sites and only 8 percent of comparison sites had road curvature greater than 6 deg combined with downhill gradient of -2 percent or less at or approaching the sites. Fifty percent of fatal crash sites and only 23 percent of comparison sites were at or near curves greater than 6 deg irrespective of gradient. A state study found that only 22 percent of roadways throughout the state had curvatures of more than 5.5 deg. Nonlocal roads accounted for 83 percent of the fatal crashes into fixed objects but comprised only 33 percent of the roads in the state. In 98 percent of the cases objects struck were within 15 m (50 ft) of the pavement edge. Top priority should be given to modification of roadside hazards on and near curves greater than 6 deg. particularly those on nonlocal roads where the downhill grades are -2 percent or less.