Driver accident risk in relation to the penalty point system in British Columbia

Abstract

Driver adjudication systems that assign penalty points to various traffic law infractions, and establish a level of point accumulation at which action to suspend drivers' licenses is taken, are a feature of the activities of virtually all motor vehicle authorities. However, in many cases the number of penalty points assigned to each infraction type is simply a qualitative assessment without any empirical foundation. The ordering of infractions by “severity” is often a very subjective process that tends to result in a linear scale of relatively narrow range. The purpose of the research reported in this paper was to assess the relative impact on future crash-involvement risk of a number of different infractions and also of accident history. A total of 1,998,347 B.C. drivers' records was examined. Logistic regression analysis was employed to identify drivers who were most likely to have one or more at-fault accident involvements in a postperiod on the basis of their preperiod records of at-fault accident involvements and convictions. The results showed a consistent increase in postperiod accidents per driver with increasing preperiod numbers of both crashes and convictions. It was also found that prior at-fault accident involvements were a better predictor of future at-fault accident involvements than were prior convictions, and that up to 23% more high-risk drivers could be identified by making use of prior atfault accident involvements as opposed to convictions alone. Right-of-way infractions such as “failure-to-yield” and disobeying a traffic signal were found, after accidents, to be the type of preperiod incidents most strongly associated with postperiod crashes.