Citation

Blensly RC, Head JA. Highw. Res. Board bull. 1960; 266: 28-33.

Copyright

(Copyright © 1960, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Several studies have been made attempting to determine the relationship between the frequency of accidents and the width of shoulders on 2-lane rural highway sections. This report brings together the information available from these past studies and correlates them with oregon's concluding research on this phase. The studies of gravel shoulders on 2-lane rural highways have indicated a tendency for total accidents and property-damage accidents to decrease as the shoulder width increased for the intermediate traffic volume ranges. No relationship was indicated for the low and high traffic volume ranges, nor was any relationship found for personal-injury accidents. In contrast to the gravel shoulder studies, the studies of paved shoulders on 2-lane rural highways have indicated a tendency for total accidents and property-damage accidents to increase as the paved shoulder width increased. For personal-injury accidents the same relationship has been indicated in one study, but was not found in another study. In summary, it appears rather certain that higher average accident frequency occurs on sections having wide paved shoulders. The findings of the studies could be stated to the effect that it cannot be shown that increasing the width of paved shoulders is actually helpful in reducing accident frequency on 2-lane rural highways. Although there appears to be an adverse relationship between shoulder width and accidents, it must be kept in mind that this is only one element of many governing the selection of proper shoulder width.