Previous causal analysis has failed to demonstrate the deterrent effectiveness of tough Scandinavian drinking-driving laws. In contrast to earlier research which examined legal threat as the sole determinant of control (simple deterrence), the present investigation was more broadly construed to include a range of other social and psychological influences (general deterrence). The findings tend to support Andenaes' theory of general prevention, and they raise fundamental questions about treating law as a simple intervention which is wholly amenable to causal analysis. Tables and approximately 50 references. (Author abstract)