IDENTIFICATION OF COUNTERMEASURES TO REDUCE SEVERITY OF RURAL HIGHWAY CRASHES

This report presents the details of an investigation aimed at finding potential countermeasures to enhance safety of rural highways by identifying critical factors contributing towards higher severity of crashes. Crash data was analyzed and crash severity was modeled using several statistical modeling approaches, including ordered choice models. A number of contributing factors, which could be categorized as driver related, environmental related, roadway related, vehicular and crash related were considered in the analysis process and critical ones were selected. Results indicated that many driver related factors such as alcohol involvement, lack of seat belt usage, excessive speed, and driver ejection or being trapped due to the crash are contributory towards increased severity of crashes on rural highways. It also showed that the severities of single vehicle crashes are higher as compared to two- vehicle and animal-vehicle crashes. However, when two vehicles collide, head-on, angle, rear-end, and sideswipe collisions have higher propensity of resulting in higher severities. Roadway geometry related parameters such as cured and graded roads are also contributory towards increased crash severity in rural areas. In contrast, under wet road surface conditions, the probability of having a more severe crash is low. Based on the identified critical factors that contribute towards increased severity, potential countermeasures have been suggested with the intention of improving highway safety in rural areas.