How do helmet laws affect motorcyclist deaths and injuries?
In states that either reinstated or enacted universal motorcycle helmet laws, helmet use increased dramatically, and motorcyclist deaths and injuries decreased. In states that repealed or weakened their universal helmet laws, helmet use declined sharply, and motorcyclist deaths and injuries rose. In two studies published in 2007 and 2008, researchers modeled state motorcyclist fatality rates by helmet law type, after controlling for various factors such as per capita income, population density, and annual precipitation. Death rates were lowest in states with helmet laws that cover all riders. Rates in states with helmet laws that cover only some riders were lower than those in states with no helmet law, but not as low as rates in states with helmet laws that cover all riders. These results held for all three types of rates considered: deaths per 10,000 registered motorcycles, deaths per 100,000 population, and deaths per 10 billion vehicle miles traveled.12,13 Some examples of helmet l
