United States: Do Partial Coverage Laws Work?

In the United States, each State decides whether or not motorcycle operators and their passengers are required to wear helmets in their state. Until 1995, the federal government used grants as well as sanctions to get states to require that all motorcyclists of all ages to wear helmets ( “universal laws”). But lawmakers and motorcyclists raised concerns that these laws were infringing on personal rights, and in 1995, the federal government eliminated the sanctions and grants that encouraged passage of universal helmet laws. In response, several states modified their universal laws to partial coverage laws that require only riders younger than 18 or 21 years wear helmets. Those riders older than the minimum were not required to wear helmets. By the end of 2004, 20 states had universal laws, 24 states had partial coverage laws, and 4 (Colorado, Illinois, New Hampshire, and Iowa) had no laws at all.

David Houston and his colleague, Lilliard Richardson, two political scientists, examined the implications of changes in motorcycle helmet safety laws by conducting a cross-sectional time-series analysis of data from the 50 states during the period 1975 through 2004. Their results showed that, on the average, when states with universal laws were compared to states with no helmet mandates, there was an 11.1% reduction in motorcyclist fatality rates. States with partial coverage laws had fatality rates that were not statistically different from those states with no helmet laws. In those states where universal coverage laws had been repealed, the fatality rate increased by an average of 12.2% over what would have been expected had the laws not been changed. The study authors estimated that there were an additional 615 motorcycle fatalities in those states that changed from universal to partial helmet laws during the period 1997-2005.

The authors concluded that motorcycle safety had been compromised in those states that had repealed their universal coverage laws. This trend is likely to be seen in other states if they abandon their universal laws.

Houston DJ, Richardson LE. Motorcycle safety and the repeal of universal helmet laws. AJPH 2007:97;2063-2069.

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