Bicycle helmets are an effective way to prevent mortality and morbidity from bicycle crash-related head injuries. In spite of their documented effectiveness, only about 18% of bicyclists in the United States regularly wear helmets. Educational strategies including school education programs, subsidies, and community activities have been used in to increase helmet use. They have had moderate results. In 1990, Victoria, Australia implemented legislation to require that all bicyclists wear helmets. Helmet use among bicyclists immediately increased from 38% to 78%. We will compare the effectiveness of laws requiring helmets with other strategies designed to increase helmet use and examine the impact these laws have had on injuries and bicycle ridership.