Trends in deaths due to motorcycle crashes and risk factors in injury collisions

In the past 25 years, the numbers of registered motorcycles in the United States and California have increased about 1000 and 1100%, respectively. In the same period, the motorcycle collision death rate per million population more than doubled. The purposes of the study were to examine time trends in deaths due to motorcycle collisions, examine a methodologic problem in the study of motor vehicle collision death rates, and to determine driver and vehicle factors which may discriminate in the production of motorcycle crash related injurites.

With the exception of 1974, the increase in the ratio of registered motorcycles per 100,000 population in the United States corresponded to an increase in the crude death rate per million population. A similar pattern was also found in California.

Stepwise discriminant analysis was used to determine an optimum set of factors associated with motorcycle collision injuries. The analysis indicated that for male drivers age was the single factor most significantly related to motorcycle collision injuries. Other factors, in addition to age, which added to the power of the discrimination included number of prior motorcycle driving violations, frequency of motorcycle use, number of prior motorcycle crashes, motorcycle drivers' training, and height of the drivers.