Analysis of Injury Severity of Drivers Involved in Single-Vehicle and Two-Vehicle Crashes on Ontario Highways Using Heteroscedastic Ordered Logit Models

摘要

The objective of this study is to analyze driver’s injury severity in single-vehicle and two-vehiclecrashes and compare the effects of explanatory variables between various types of crashes. Thestudy identified factors affecting injury severity and their effects on severity levels using 5-yearcrash records for provincial highways in Ontario, Canada. Considering non-uniform variations inunobserved effects of explanatory variables on injury severity among observations called“heteroscedasticity”, heteroscedastic ordered logit (HOL) models were developed for singlevehicleand two-vehicle crashes separately. The results show that there exists heteroscedasticityfor some variables in both single-vehicle and two-vehicle crash models. The results also showthat some factors have opposite effects between single-vehicle and two-vehicle crashes, andbetween car-car crashes and truck-truck crashes. The study demonstrates that HOL models usingseparate crash data sets classified by vehicle type can better capture the associations of variableswith driver’s injury severity.