Effectiveness of a law to reduce alcohol-impaired driving in Japan.

OBJECTIVE To estimate the effect of a new road traffic law against alcohol-impaired driving in Japan. METHODS Japan passed a new road traffic law in June 2002 intended to reduce alcohol-impaired driving by decreasing the permissible blood alcohol level and by increasing penalties. Using data collected from police reports, the number of traffic fatalities and injuries were analyzed by time series. RESULTS Simple comparisons of the average of all severe traffic injuries, traffic fatalities, alcohol-impaired traffic injuries, alcohol-impaired severe traffic injuries, and alcohol-impaired traffic fatalities per billion kilometers driven showed reductions after enactment of the new road traffic law in June 2002. The rate of alcohol-related traffic fatalities per billion kilometers driven decreased by 38% in the post-law period. In segmented regression analyses with adjustment for baseline trends, seasonality, and autocorrelation, all traffic injuries, severe traffic injuries, alcohol-impaired traffic injuries, alcohol-impaired severe traffic injuries, and alcohol-impaired traffic fatalities per billion kilometers driven declined significantly from baseline after the new traffic law. CONCLUSION Large, immediate public health benefits resulted from the new road traffic law in Japan.