Tokoro, M., Kokushikan University, Japan
Japanese drivers of 75 years and older have been legally obligated since 1998 to undergo a special driving aptitude test upon renewal of their driving license. The purpose of the test is not to find fault with and then exclude elderly drivers, but to administer safety education and properly improve their driving behavior. It is found that people who are prone to cause accidents have a peculiar property in that their motor reaction is more dominant than their sensory reaction. The test is, however, chiefly designed to measure reaction time, and does not comprise estimations of either motor reaction or sensory reaction. In order to meet the purpose of the test it is necessary to measure these two reactions. The aim of the study is to illuminate the importance of the two elements previously excluded from the present test. We used the Discriminative Reaction Test of Multiple Performance Type to estimate both of the aforesaid elements. The subjects were 513 male professional drivers from a large transportation firm. Forty-six of them were age 55 and older, and the rest, 467, were under 55. The results showed that the older group achieved a lower score than the younger group concerning the dominance in their motor reaction. A low-risk-taking approach to driving is the important factor in compensating for the decline in psychomotor skills caused by aging. We believe that it is necessary to let older people realize these facts in the special driving aptitude test for the elderly.