Researchers evaluated the association between motorcycle licensing and operation regulations and motorcycle mortality rates in the U.S between 1997 and 1999. MAIN FINDING(S): Mortality rates tended to be significantly lower in states with the following motorcycling requirements: skill test for a motorcycle permit, driver training, longer duration of learner's permits, and a full helmet law. RESEARCH CONCLUSIONS: "Specific motorcycle licensure policies appear to be associated with lower mortality rates