Identification of factors associated with various types of impaired driving

Despite significant progress in reducing impaired driving, impaired drivers are still a public threat to themselves and others. Studying all types of drivers’ impairment is especially important as impairment in the literature has been mainly looked at from an angle of the driving under the influence (DUI). In other words, there is a definitional ambiguity regarding the impaired driving in the literature review. Addressing that unclarity is especially important as while many considered impaired driving such as distraction and fatigued driving are similar to DUI, they account for a higher proportion of fatalities on roadway, compared with DUI. Thus, first we highlight links between DUI and other impaired driving based on the literature review, and then this study highlighted factors associated with various impaired driving so drivers’ actions and behaviors could be addressed more efficiently. Here, in addition to DUI, impaired drivers are defined as whether drivers were fatigued, distracted, or under some emotional conditions at the time of crashes. Multinomial logit model (MNL) was extended to a model excluding or equating some coefficients across categories, making parameters’ estimates more robust. The analysis results highlighted, for instance, types of vehicles that the drivers own, drivers’ gender, age, seatbelt use, and various drivers’ actions such as failure to keep the proper lane and following too close are associated with various impaired drivers’ actions. These associations are expected to be related to unseen drivers’ characteristics that were not recorded at the time of crashes. This is one of the earliest comprehensive studies, investigating the association of various factors and different types of impaired driving.