The Japanese population is aging rapidly, raising the number of traffic accidents involving elderly drivers. In Japan, single-vehicle accidents are a serious problem because they often result in fatalities. We analyzed these accidents by vehicle type, age group, and driving area. To examine the risk of accidents of the elderly drivers, their driving frequency needs to be considered, which is less. Moreover, it is difficult to know the actual distance driven by them. Therefore, in this article, based on the assumption that the number of rear-end collisions is a proxy for the traffic volume, we used the number of such collisions as a control for the driving frequency. It was found that in single-vehicle accidents, elderly drivers were at higher risk than other age groups, especially when driving light motor vehicles (K-type vehicles) in non-urban areas. A possible explanation is the higher frequency with which the elderly drive K-type vehicles in areas where there are few other vehicles on the road.
