Increased fatalities after motorcycle helmet law repeal: is it all because of lack of helmets?

Abstract

Background: During the last 10 years, the number of motorcycle riders in the United States has risen sharply. The corresponding increase in fatalities observed during this time may be because of the increase in riders, or because the number of states that mandate universal helmet use has decreased. We examined the effect of the repeal of Florida's helmet law in July 2000 to test the hypothesis that the increase in fatalities observed after repeal resulted from an increase in the number of motorcycle riders.

Methods: We identified all motorcycle fatalities (N = 197) in Miami-Dade county for a 3.5-year period before repeal (prelaw), and a similar period after repeal (postlaw), using police crash reports and medical examiner records. We compared the number of fatalities, frequency of helmet use in fatal crashes, and number of registered motorcycles in the two time periods.

Results: There was a decrease in helmet use from 80% to 33%, and an increase in motorcycle fatalities after repeal: 72 to 125. However, repeal was also associated with a rise in annual motorcycle registrations from 17,270 to 39,043. Fatality rates adjusted for numbers of registered motorcycles did not change significantly; 11.6 deaths per 10,000 motorcycles prelaw, and 12.5 deaths postlaw.

Conclusions: There was a significant rise in motorcycle fatalities after Florida's helmet law repeal, which appears to be associated with an increase in the number of motorcycle riders. Injury prevention efforts focusing on factors other than helmet use should be developed in light of continuing repeal of universal motorcycle helmet laws across the nation.