Bicycle-related head injuries are an important cause of injury and death in the United States, especially among children. There is evidence that widespread use of protective bicycle helmets could markedly decrease the rate of serious head trauma among injured bicyclists, but most cyclists do not wear helmets. Efforts to increase the rate of helmet use have been undertaken in physicians' offices, schools, community-wide programs, and through legislative initiatives. Although some of these interventions have increased helmet use, none has been shown to result in helmet use by the majority of bicyclists.