Citation

Greenshields BD. Highw. Res. Board bull. 1959; 208: 1-15.

Copyright

(Copyright © 1959, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

This is a report of an attempt to find if there is a correlation between the quality of traffic flow and the frequency of highway accidents. The term quality characterizes the traffic steam and indicates the manner in which vehicles move. In making the study three sections of highway with different accident frequencies per million vehicle-miles were selected for investigation. Two of the sections are two-lane and the third is three-lane. The accident frequencies and the corresponding quality indices are mentioned according to road, quality index, and accidents per million vehicle miles. The three-lane road with the highest quality index did not have the lowest accident rate. This indicates that there is no direct correlation between the index and accident frequency. On the other hand, it could reveal that a three-lane road should not be compared with a two-lane. Furthermore, it could be that single vehicle accidents are a better basis for a comparison of the types of roads. The fact that there were more accidents on the curving road than on the straighter one, points to the need for including change of vehicle direction as well as change of speed in the quality index. The results of this limited study show that improving the quality of traffic flow should reduce accidents. Apparently the inherent characteristics of flow in a traffic steam tend to make it safe or hazardous.