The percentages of fatally injured drivers with blood alcohol levels exceeding .00, .07, .09, and .19 percent were used as indicators of drunk driving. Comparison focused on States that had introduced severe, mandatory penalties during the study period and seven States that had made no change in penalty. It was found that drunk driving declined in all 14 States between 1980 and 1985. The decline in drunk driving fatalities was greater at higher BAC levels than at lower ones. For BAC of 20 percent or more, the decline was nearly 20 percent. There was no indication that the decline was greater in States that had increased the severity of sanction than in States that had not. Although there is no indication that severe sanctions had a beneficial effect with respect to the measures used in this study, the possibility that they might have had more subtle effects cannot be ruled out. For instance, it is possible that some States had worse than average trends prior to the introductions of the severe sanctions and that these were reversed, or that States where severe sanctions were not mandatory did, in fact, apply severe sanctions extensively. 17 figures and 3 references. (Author abstract modified)