Wisconsin motorcycle accident data three years before and three years after repeal of a mandatory helmet law were collected and analysed in this study. Wisconsin enacted a mandatory helmet law for all motorcycle riders in 1968. The law remained in effect until it was repealed, on March 19, 1978. Prior to the repeal, in the years 1975, 1976, and 1977, virtually all riders wore helmets. During the three years after repeal (1978, 1979, 1980) helmet use was substantially reduced. The number of fatalities per 100 riders involved in accidents was used as the primary unit of measure. The "control" mechanism was the injury data for other parts of the body (arms, legs and trunk) unaffected by helmet use or nonuse. The study found that unhelmeted cyclists involved in accidents suffered head injuries at a rate of 40.64 per 100 riders, and 2.24 of every 100 unhelmeted riders died of head injuries. Of every 100 helmeted riders involved in an accident, 23.57 suffered head injuries and 1.25 died of head injuries. The rate of injury to arms, legs and trunk remained virtually constant from the three mandatory helmet years before repeal through the three years following repeal, for both helmeted and unhelmeted riders. The only increase noted was in head injuries to unhelmeted riders. Blood samples submitted by coroners showed that 47.9 percent of all fatally injured motorcycle drivers were legally intoxicated. A total of 73 percent of the intoxicated fatal drivers were involved in single vehicle accidents with blood alcohol levels averaging over .20 percent, which is twice the legal level of intoxication in Wisconsin.
Abstract