Factors associated with crash severity on rural roadways in Wyoming

Abstract The ability to identify risk factors associated with crashes is critical to determine appropriate countermeasures for improving roadway safety. Many studies have identified risk factors for urban systems and intersections, but few have addressed crashes on rural roadways, and none have analyzed crashes on Indian Reservations. This study analyzes crash severity for rural highway systems in Wyoming. These rural systems include interstates, state highways, rural county local roads, and the roadway system on the Wind River Indian Reservation (WRIR). In alignment with the Wyoming strategic highway safety goal of reducing critical crashes (fatal and serious injury), crash severity was treated as a binary response in which crashes were classified as severe or not severe. Multiple logistic regression models were developed for each of the highway systems. Five effects were prevalent on all systems including animals, driver impairment, motorcycles, mean speed, and safety equipment use. With the exception of animal crashes, all of these effects increased the probability that a crash would be severe. Based upon these results, DOTs can pursue effective policies and targeted design decisions to reduce the severity of crashes on rural highways.