To determine if these amendments reduced the magnitude of the drinking and driving problem in Canada and whether the effect was more pronounced among certain population subgroups, data on drinking and driving behavior and its consequences were examined. Data analysis provided clear and conclusive evidence that substantial and dramatic reductions in drinking and driving occurred in Canada during the 1980's. Between 1980 and 1991, the percent of alcohol-related driver fatalities decreased from 60 to 46 percent, the percent of driver fatalities with blood alcohol concentrations in excess of 80 mg percent decreased from 49 to 39 percent, the percent of drivers involved in personal injury crashes who had been drinking decreased from 12 to 7 percent, and the number of persons charged with a drinking and driving offense decreased by 29 percent. In addition, the percent of night drivers who had been drinking decreased and the prevalence of self-reported driving after drinking at the end of the decade was about half that reported earlier in the decade. Despite substantial reductions in the magnitude of the drinking and driving problem, no evidence specifically attributed these reductions to the 1985 legislative amendments. Reductions that occurred after the amendments were consistent with pre-existing trends. It was also evident that observed changes in drinking and driving were not equivalent across all driver subgroups or crash types. In terms of alcohol-related driver fatalities, reductions were greatest among men, younger drivers, single vehicle crashes, motorcycle operators, and crashes occurring on the weekend compared to weekdays. Recommendations to enhance the impact of the 1985 legislative amendments are offered. 51 references and 47 figures