Abstract
Many rigorous studies have shown the effectiveness of helmet use in reducing severe injuries and fatalities to motorcyclists. NHTSA reports estimates of lives saved by U.S. motorcyclists wearing or potentially wearing helmets. This calculation uses a statistically derived estimate of helmet effectiveness in preventing deaths to motorcyclists involved in crashes. Two parts of the estimate of lives saved are (a) deaths prevented assuming crashes occurred that did not kill helmeted motorcyclists in proportion to those that did kill helmeted motorcyclists and (b) deaths that may have been prevented if unhelmeted motorcyclists killed in crashes had been helmeted. Similar estimates can be made for injuries. More readily available crash data enable analysts to investigate whether crashes in their jurisdictions support the inherent assumptions of these estimates. Moreover, the estimates can be stratified to include other crash characteristics such as crash type and rider gender and age. This study compared estimates of potential fatality and injury reductions based on NHTSA averages with estimates with the use of all reported crashes on Colorado state and federal roads in the years 2006 to 2014. Helmet effectiveness is found to depend on crash characteristics in Colorado and does vary from national averages.