The Impact of Driver Alcohol Use on Crash Severity: A Crash Specific Analysis

This study uses a crash specific data set that is supplemented with location based socioeconomic data to estimate the impact of driver alcohol use on average crash severity. Logit estimates indicate that crashes in which the at-fault drivers had been drinking are more likely to result in a severe injury or death than are crashes caused by sober drivers. Ordered logit estimates indicate that at-fault driver alcohol use increases the expected highest degree of injury resulting from a crash, and Tobit estimates indicate that the number of injuries or deaths per crash increase an average of 0.71 when the at-fault driver has been drinking. Moreover, at-fault driver alcohol use worsens the severity of crashes relative to not-at-fault parties. Collectively, these results indicate that at-fault drinking drivers are involved in more violent crashes and produce more serious injuries to not-at-fault parties than at-fault sober drivers.