Motorcycle safety and the repeal of universal helmet laws.

Objectives: We assessed the implications for motorcyclist safety of recent repeals of universal helmet laws in 6 US states.

Methods: We examined cross-sectional time-series data from the 50 states and the District of Columbia for the period 1975 through 2004.

Results: On average, when compared to state experience with no helmet mandate, universal helmet laws were associated with an 11.1% reduction in motorcyclist fatality rates, whereas rates in states with partial coverage statutes were not statistically different from those with no helmet law. Furthermore, in the states in which recent repeals of universal coverage have been instituted, the motorcyclist fatality rate increased by an average of 12.2% over what would have been expected had universal coverage been maintained. Since 1997, an additional 615 motorcyclist fatalities have occurred in these states as a result of these changes in motorcycle helmet laws.

Conclusions: Motorcyclist safety has been compromised in the states that have repealed universal coverage and is likely to be compromised in other states that abandon these statutes.