Citation

Urbanik II T, Hinshaw W, Fambro DB. Transp. Res. Rec. 1989; 1208: 23-35.

Copyright

(Copyright © 1989, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The safety effects of limited sight distance at crest vertical curves on two-lane rural highways in Texas were examined. Two large data bases consisting of 222 study segments of approximately one-mile lengths representing nearly 1,500 accidents were assembled to evaluate the effects that stopping sight distance along crest vertical curves has on accident rates. It was found that the relationship between available sight distance on crest vertical curves on two-lane roadways and accidents is difficult to quantify, even when a large data base exists. The AASHTO stopping sight distance design model alone is not a good indicator of accident rates on two-lane roadways in Texas; thus, use of this model alone will not result in cost-effective project design. Where there are intersections within the limited sight distance sections of crest vertical curves, there is a statistically significant increase in accident rates. It can be inferred that other geometric conditions within limited sight distance sections of crest vertical curves could also cause a marked increase in accident rates. An example would be a sharp horizontal curve hidden by a crest vertical curve. The increase in accident rates because of intersections within limited sight distance sections of crest vertical curves was more pronounced on roadways with higher volumes, implying that a threshold volume level may be determined based on considerations of cost effectiveness.

Record URL:
http://onlinepubs.trb.org/Onlinepubs/trr/1989/1208/1208-004.pdf

Language: en

Keywords

Highway Engineering; Roads and Streets--Visibility; Highway Systems--Accidents