Understanding the Severity of Truck-Involved Crashes on Mountainous Expressways Considering Vehicle Types and Road Alignment Specifications

Truck-involved accidents are a concern for transportation sectors and can result in property loss as well as casualties. The influencing factors of the severity of truck-involved crashes are analyzed using crash data on a mountainous expressway in China as an example. An ordered logistics model is built considering the specification of vehicle types and classification of road alignment condition. Results show that vehicle types involved in a crash have a significant effect on the severity of truck-truck crashes. Moreover, the probability for truck-involved crashes with higher severity gradually decreases with the increase of the curve radius. Also, flat grade sections have a higher probability of severe crashes than upgrade sections. Conclusions obtained here could provide important implications for both road designer and transportation management agencies to further improve traffic safety for mountainous expressways with a high truck mix rate.