IDENTIFICATION OF FACTORS RELATED TO URBAN AND RURAL HIGHWAY CRASHES

This paper presents the details of an investigation aimed at identifying critical factors contributing towards higher crash severity in rural and urban highway crashes. Ordered probit models were used to analyze the crash data from KARS (Kansas Accident Reporting System) database. Both urban and rural crashes were considered separately in this analysis and five categories of contributory factors, driver, vehicular, roadway, environmental and crash related, were included in the models. The results of this study showed that most of the contributory factors, which contribute towards crashes resulting in higher severities, are common for urban and rural crashes. 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 more critical in resulting more severe crashes. It also showed that roadway geometry related parameters such as curbed and graded roads are more contributory towards higher crash severity. In two vehicle crashes, when the collision type is head-on, angle or rear-ended, the propensity of resulting in a more severe crash is high in both rural and urban highways. In rural areas, single vehicle crashes are significant towards higher severities compared to two vehicle crashes and animal vehicle crashes, but in urban areas both single and two vehicle crashes are significant. In contrast, under wet road surface conditions the probability of having a more severe crash is low in rural areas. The reason might be the reduced speeds due to driver cautiousness under such conditions.