Investigations about driver behavior and accident experiences at curved sites (including black spots) of two- lane rural highways in the U.S.A.

Findings of an analysis to evaluate the impact of design parameters, posted recommended speed signs and traffic volume on operating free speeds (85th- percentile speeds) and accident rates on 322 curved roadway sections, of varying degrees of curve, of two- lane rural U.S. state highways, are presented. Regression analyses techniques revealed that the 85th- percentile speed and accident rate in a curve could be estimated by using the characteristics of the curve.