Helmet characteristics and injury outcomes among collision-involved motorcyclists in California

Purpose: In this analysis we summarize patterns of helmet use among more than 8,000 collision-involved motorcyclists and examine how helmets of varying types protect against head injury and fatality. Methods: The California Highway Patrol used a one-page supplemental form to collect information on helmet characteristics, helmet certification, helmet retention, body region injured, and other motorcyclist behaviors. The form was used during all CHP motorcycle collision investigations from August 2012 through July 2013. Results: We analyzed preliminary data on 6,754 collision-involved motorcycles that were carrying 7,111 persons. Of these riders, 65% were wearing a full-face helmet, followed 13% with ½-helmets, 8% with ¼-helmets, 7% with bogus helmets, 5% with modular helmets, and 2% with no helmet. Bogus helmets were those that were determined by the officer to be non-DOT-compliant or that had no DOT or Snell label. Compared with riders wearing full-face helmets, those wearing bogus helmets were 2.5 times as likely to suffer head injury (RR 2.5; 95% CI 2.08-2.90) and twice as likely to suffer fatal injury (RR 2.01; 95% CI 1.29-3.14). No other helmet type differed significantly from full-face helmets in terms of the risk of fatality. Helmet type was not associated with the probability of neck injury (p=0.93). Conclusions: This is one of few studies to use detailed information on helmet characteristics collected independently of injury outcome. We demonstrate that bogus helmets offer inadequate