The role of exposure, experience and demerit point levels in the risk of collision

Abstract To study the relationships between exposure, collisions, and certain characteristics of drivers, a survey of approximately 3000 licensed drivers was carried out among residents of Toronto, Canada. Drivers were chosen randomly from the file of licensed drivers for both sexes at different levels of demerit points. Telephone interviews were used to collect data on the amounts and type of driving done in the previous week. These results and the collision experience of interviewed drivers were used to calculate annual collision rates per million driver-km. These rates were used to calculate the number of collisions expected to occur given the amounts of driving reported on certain types of road and times of day. Comparison of these figures with the number of collisions actually experienced in these circumstances indicated an increased hazard of city streets for all drivers and increased hazard of driving after dark for older drivers. The level of demerit points—indicator of the driver's recent conviction for traffic violations—was not associated with risk of collision if exposure was accounted for, except in drivers who typically drove small amounts. These results suggest that experience is an important benefit of high exposure for many drivers and may protect them from collisions in some circumstances. This has implications for the training and licensing of new drivers and for the need for continuing education of “high risk” drivers with low exposure.