Impacts of Work Zone Component Areas on Driver Injury Severity

The establishment of work zones along roadways is considered a necessity for the construction of new roadways, the maintenance of deteriorating structures, and to provide access for the installation and maintenance of utilities. This study attempts to investigate the risk factors contributing to driver's injury severity in the different areas that constitute the formation of roadway work zones. The injury severity outcomes of a crash have a natural and discrete ordering, and therefore this study has adopted the mixed generalized ordered response probit (MGORP) model. As compared to the standard ordered response probit model (ORP), which is widely utilized in the injury severity literature, the MGORP framework has the ability to recognize not only the ordering of the injury severity categories, but also allow for the investigation of unobserved effects of risk factors, known in the literature as unobserved heterogeneity. The empirical analysis was conducted using a database that consisted of 10 years of work zone crashes. This database was available through the Highway Safety Information System (HSIS). Elasticity analysis suggests that airbag deployment, alcohol involvement, ejection, seatbelt use, and partial control of access are key factors contributing to the likelihood of severe outcomes. Additionally, the effects of several covariates were found to vary across the different work zone component areas where crashes have occurred.