Citation

Barbaresso JC. Transp. Res. Rec. 1984; 956: 25-29.

Copyright

(Copyright © 1984, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

n this study the relative accident impacts of flashing signal operation and stop-and-go signal operation in Oakland County, Michigan, were evaluated. Analyses were conducted to determine (a) if an accident problem exists at intersections where signals are in a flashing mode during off-peak, nighttime hours; (b) what levels of accident experience can be expected under different conditions and signal operations; and (c) appropriate criteria for making signal-operation decisions for off-peak, nighttime hours. The results of the study indicated that right-angle accidents are significantly overrepresented at four-legged, arterial intersections when signals are in a flashing mode during nighttime hours. A before-and-after analysis demonstrated that the severity of up to 100 percent of late night right-angle accidents can be reduced by eliminating flashing signal operation, with no significant effect on the frequencies of other accident types. The elimination of flashing signal operation appears to be effective in reducing nighttime, right-angle accident frequency and road agency liability exposure both at individual locations and systemwide. Factors that were found to be related to the level of right-angle accidents at flashing signal locations include (a) intersection type (i.e., three-legged or four-legged); (b) the functional classification of the intersecting roadways; (c) the hourly volume ratio (i.e., main street traffic volume to minor street traffic volume); (d) driver impairment; and (e) time of night. When making decisions regarding signal operation during off-peak, nighttime hours, right-angle accident frequency and rate should be primary factors in the decision-making criteria. Other criteria for making signal-operation decisions are presented for use when conditions favor the occurrence of right-angle accidents but none occurred during the review period.

Language: en

Keywords

TRAFFIC SIGNS, SIGNALS AND MARKINGS; ROADS AND STREETS - Intersections; ACCIDENT PREVENTION - Efficiency