Policies to reduce alcohol-impaired driving : evaluating elements of deterrence.

This study assesses state policies toward alcohol-impaired driving, a major threat to traffic safety and a cause of highway casualties. State laws and policies seek to deter such behavior by improving the certainty, severity, and celerity of punishment. A pooled cross-sectional time series regression analysis of the 48 contiguous states is utilized to estimate the effects of the three components of deterrence in conjunction with a set of environmental control variables. Of the deterrence-based variables, per se laws and administrative licence suspension are found to have the greatest impact on single-vehicle nighttime fatalities. In contrast, laws which attempt to increase the severity of punishment have virtually no effect.