carrying motorcycles are not overrepresented in the accident data. The drivers of the other vehicle involved in collision with the motorcycle are not distinguished from other accident populations except that the ages of 20 to 29, and beyond 65 are overrepresented. Also, these drivers are generally unfamiliar with motorcycles. The large displacement motorcycles are underrepresented in accidents but they are associated with higher injury severity when involved in accidents. Any effect of motorcycle color on accident involvement is not determinable from these data, but is expected to be insignificant because the frontal surfaces are most often presented to the other vehicle involved in the collision. Motorcycles equipped with fairings and windshields are underrepresented in accidents, most likely because of the contribution to conspicuity and the association with more experienced and trained riders. Motorcycle riders in these accidents were significantly without motorcycle license, without any license, or with license revoked. Motorcycle modifications such as those associated with the Semi-Chopper or Cafe Racer are definitely overrepresented in accidents. The likelihood of injury is extremely high in these motorcycle accidents; 98% of the multiple vehicle collisions and 96% of the single vehicle accidents resulted in some kind of injury to the motorcycle rider; 45% resulted in more than a minor injury. Half of the injuries to the somatic regions were to the ankle-foot, lower leg, knee, and thigh-upper leg. Crash bars are not an effective injury countermeasure; the reduction of injury to the ankle-foot is balanced by increase of injury to the thigh-upper leg, knee, and lower leg. The use of heavy boots, jacket, gloves, etc., is effective in preventing or reducing abrasions and lacerations, which are frequent but rarely severe injuries. Groin injuries were sustained by the motorcyclist in at least 13% of the accidents, and typified by multiple vehicle collision in frontal impact at higher than average speed, Injury severity increases with speed, alcohol involvement and motorcycle size. Seventy-three percent of the accident-involved motorcycle riders used no eye protection, and it is likely that the wind on the unprotected eyes contributed an impairment of vision which delayed hazard detection. Approximately 50% of the motorcycle riders in traffic were using safety helmets but only 40% of the accident-involved motorcycle riders were wearing helmets at the time of the accident. Voluntary safety helmet use by those accident-involved motorcycle riders was lowest for untrained, uneducated, young motorcycle riders on hot days and short trips.