Motorcycle helmet laws in the United States from 1990 to 2005: politics and public health.

The passage of universal helmet legislation requiring motorcycle riders of all ages to wear helmets is a timely and controversial issue with far-reaching public health implications, especially as the number of motorcycle fatalities continues to rise. In 2008, only 20 states had a universal helmet policy, an effective safety measure for reducing motorcycle fatalities and serious injuries. We used state-specific longitudinal data for the continental United States from 1990 through 2005 to determine which industry, political, economic, and demographic factors had a significant influence on the enactment of universal helmet policies. Our findings suggest that political climate and ideology are important predictors of helmet policies.