Measuring and understanding the association between license-related infractions and road crash severity

Abstract The relationship between license-related infractions (LRIs) and the severity of road crashes has been scarcely addressed in previous research. This study estimates the association between each LRI and the severity of driver injuries and the partial severity of the crash (i.e., crash severity after excluding the severity of the driver’s own injuries) in a cohort comprising 78,720 drivers who were considered responsible for crashes in the Spanish National Register for Road Traffic Accident Victims, from 2014 to 2017. Adjusted Relative Risk Ratios for each LRI and severity level were obtained through multinomial logistic regression models. Age- and sex-adjusted estimates revealed an increased severity for almost all LRIs. Additional adjustment for seat belt use showed a decrease in the magnitude of the associations, particularly regarding driver injury severity, suggesting that part of these associations was related to increased vulnerability of the driver. Adjustment for other vehicle- and environment-related variables showed a further decrease in the associations but remained significant for “never having obtained a license” and other specific LRIs. These results support the need for maintaining police surveillance and legal measures to identify these subgroups of drivers, remove them from the road and adopt strategies for their safe return to driving.