Citation

Haywood JC. Transp. Res. Rec. 1980; 757: 22-25.

Copyright

(Copyright © 1980, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Horizontal alignment and superelevation of curves have an impact on the traffic safety performance of highway sections. Research that relates traffic safety to roadway horizontal alignment has consistently shown that traffic accidents increase with increasingly sharper curves. Sharp curves in segments that otherwise have good alignment tend to surprise drivers and create even more hazardous situations. Consistency in design speeds along significant sections of highways has been advocated by some as a means of controlling the incidence of surprise curves in otherwise gentle alignments. However, design speeds for horizontal curves are a function of the maximum superelevation policies adopted by a design agency. Therefore, a single curve design may be regarded as having different design speeds by agencies that have different maximum superelevation policies. For this reason, the use of resign-speed criteria for identifying potentially hazardous horizontal alignments would not appear to be appropriate. This finding is discussed in relation to the resurfacing, restoration, and rehabilitation projects proposed by the American Association of State Highway and Transportation Officials.