Epidemiology of older driver crashes – Identifying older driver risk factors and exposure patterns

The crash involvement of any road user is a function of two sets of factors: risk, which covers aspects relating to the individual road user, to his or her vehicle and to the road environment through which he or she is travelling; and exposure, the amount of travel under the different combinations of risk aspects.The ever-growing body of research covering older drivers has shown that this road user group has distinct risk factors, relative to young and middle-aged drivers. For example: frailty and hence vulnerability to injury in the event of a crash; for many, a general slow-down in physical, sensory and cognitive functioning; and for some, the onset of specific conditions leading to significant functional impairments.Many older drivers, perhaps more so than other road user groups, are aware of their heightened crash risk and have accordingly adjusted their exposure at least in part as a protective measure. In other words, they have attempted to minimise any travel under conditions that are threatening and/or cause discomfort and conversely, have attempted to restrict their travel to conditions perceived as safe and/or comfortable. This self-regulation of driving has resulted in distinct driving exposure patterns, often reflected in crash circumstances.The national fatal crash data in Australia for the period 1996–1999, have been analysed: to identify indicators of older driver risk; to identify indicators of older driver exposure patterns; and to indicate the extent to which and how the risk/exposure-reduction strategies have proven ineffective, by identifying crashes for which older drivers may be deemed responsible. Further countermeasures suggested by these analyses, have been identified.