ABSTRACT
The results of science-based epidemiological research have demonstrated that alcohol has a causal role in many motor vehicle accidents (MVAs). This research has enabled the definition by legislation of a blood alcohol concentration (BAC) above which it is unlawful to drive a motor vehicle. The laws are known as the per se laws, because the legal infringement is related solely to the magnitude of the BAC. The implementation and the persistent policing of the blood alcohol laws have been remarkably successful in reducing the incidence of alcohol-related crashes.
