Motorcycle headlight-use laws and fatal motorcycle crashes in the US, 1975-83.

Fatal motorcycle crashes in the United States from 1975 to 1983 were analyzed. In the 14 states that had motorcycle headlight-use laws during the study period, about 600 daytime crashes of the type included in the study were prevented by these laws. This reduction corresponds to a 13 per cent reduction in fatal daytime crashes and to an average reduction of about five fatal crashes per year for each of the 14 states. About 30 states did not have motorcycle daytime headlight laws in effect during the study period. If all of these states had such laws, in an average year, approximately 140 additional fatal motorcycle crashes would have been prevented.