Effectiveness of a state law mandating use of bicycle helmets among children: an observational evaluation.

In spring 1999, the authors evaluated the effectiveness of a 1997 Florida law requiring helmet use by all bicyclists younger than age 16 years. Sixty-four counties in Florida had enacted the bicycle helmet-use law, while the other three counties had opted out. Using a cross-sectional study design, the authors conducted unobtrusive observations at bicycle racks at public elementary schools statewide. Florida children riding bicycles in counties where the state helmet-use law was in place were twice as likely to wear helmets as children in counties without the law. In counties where the state law was in place, 16,907 (79%) of 21,313 riders observed wore a helmet, compared with only 148 (33%) of 450 riders in counties where no such law was in place (crude prevalence ratio = 2.4, 95% confidence interval: 2.1, 2.8). Helmet use by children of all racial groups exceeded 60% under the law. No significant difference in use by gender was found. These data support the positive influence of a law on bicycle helmet use among children. The data reinforce the Healthy People 2010 objective that all 50 states adopt such a law for children in order to increase helmet use and consequently reduce brain injury.