The purpose of this study was to examine time trends in motorcycle crash related deaths, to examine methodologic problems in the study of motor vehicle collision death rates and to evaluate the interrelationships between driver and vehicle factors which may contribute to the production of motorcycle injuries. Information on deaths, population sizes and number of registered motorcycles was obtained from the U.S. Census, the National Safety Council, and California Departments of Motor Vehicles, Finance, and Health. Data on injured motorcycle drivers in Sacramento County, California were obtained from hospital records, California Highway Patrol, Sacramento City and County police reports, self-administered questionnaires as well as driver records from the State Department of Motor Vehicles. With the exception of 1974, the average annual increase in the ratio of registered motorcycles per 100,000 population in the U.S. since 1963 corresponded to an increase in crude death rate. A similar pattern between use of motorcycles and crude death rates is found also in California. Stepwise discriminant analysis was used to identify interrelationships between factors associated with motorcycle collision injuries. The analysis indicated that for male drivers' age was the single most significant factor related to motorcycle collision injuries. Other factors included: number of prior motorcycle crashes, number of prior motorcycle driving violations, frequency of motorcycle use, motorcycle drivers' training, and height of the drivers. Among drivers more than 24 years of age, the discriminating factors included age, number of prior motorcycle crashes, and larger engine size of the motorcycle, use of eye protection, more frequent use of motorcycles, more experience driving an automobile and drivers' training. Prospective studies are clearly needed to show the precise levels of risk associated with the factors identified from this retrospective study of motorcycle crashes. The literature on motorcycle injuries is notable for the absence of specific data on the incidence of injuries. Recent estimates on the incidence of such injuries range from 350,000 for 1973 as reported by the National Safety Council to 450,000 in 1968 as reported by the National Center for Health Statistics. The paucity of specific information on factors contributing toward the incidence of motorcycle collision injuries, as well as our own experiences in Sacramento County, California, prompted us to initiate an intensive retrospective investigation of motorcycle-related injuries and deaths. Our findings on these studies in Sacramento County are reported earlier, and have documented, (1) patterns of injuries sustained in motorcycle collisions, (2) factors associated with the incidence of these collisions, and (3) factors contributing to the severity of injuries sustained.
Samenvatting