Characteristics and risk of drivers with low annual distance driven

It has been noted by several authors that risk (defined in terms of total expected numbers of crash involvements per total distance driven) paints a misleading picture of crash liability, particularly for the young and the old. They typically drive less than other age groups, and low km drivers are thought to drive under conditions that lead to higher crash rates per distance travelled. This has led to the coinage of the term "low mileage bias" to describe apparently higher risk estimates at either end of the driver age scale where these low mileage/kilometrage drivers are most common. This paper is the first to the authors' knowledge to analyse these driving patterns of low km drivers and to evaluate the risk of these patterns. It is found that older drivers who drive less tend to have higher risk per kilometre due to their mainly urban trips. Nevertheless, because those older drivers who are not low km drivers manage to minimise their risk, the overall risk of older drivers as a group is not overestimated in terms of overall crashes per total distance driven. Despite being quite different from one another, the low and high km driving patterns of younger drivers were found to impose identical risks.