What determines the (un)safety of older road users?

Answer

The road safety of older road users is largely determined by two factors: physical vulnerability and functional limitations. Both factors result in a relatively high risk of dying in a road crash. In addition, older road users often drive fewer kilometres and the conditions in which they drive are relatively dangerous: they often drive lighter cars and drive on the most dangerous roads. 

Physical vulnerability 

Older road users are physically frailer than younger adults [8]: for the same collision impact, they sustain more serious injuries. For example, for the same impact force, the fatality rate is approximately three times higher for a 70-year-old motor vehicle occupant than for a 20-year-old  [9]. Physical vulnerability has the most serious consequences when the road user is unprotected, such as when walking and cycling. For car drivers, physical vulnerability plays a lesser role, but again it affects injury severity.

Functional limitations 

With ageing, perceptual and cognitive functional limitations and disorders occur more frequently, such as reduced visual or auditory abilities, increased reaction times, and difficulties with dividing attention. However, the deterioration of these functions as it occurs with normal ageing seems to have little or no road safety consequences. Indeed, a person can often compensate for a mild single functional limitation by driving more slowly, for example [10]. Only with severe sensory, perceptual and cognitive limitations [11] [12] and in complex often unpredictable traffic situations [13] do links between functional limitations and crash involvement become apparent. In the question​​​​​​ Which disorders of older people affect road user behaviour? we also elaborate on severe functional limitations that can affect fitness to drive. 

The decline of motor functions can also increase crash risk for older road users. Broadly speaking, this motor function decline consists of slower movement, a decrease in muscle strength, a reduction in fine coordination, and a particularly sharp decline in the ability to adapt to sudden changes in posture. The latter aspect is particularly important for cyclists when maintaining balance at lower speeds (such as when getting on and off a bicycle) [14], but also for pedestrians [15]  and public transport users when walking and standing in moving buses and trains (see SWOV fact sheet Public transport and level crossings).

Other causes 

On average, car drivers aged 30-59 drove more than twice as many kilometres per year as drivers aged 70 or older during 2018-2022 (source: Statistics Netherlands). This average low annual number of kilometres of older drivers may partly explain their increased crash rate. Indeed, in general, drivers who drive a lot have a lower crash rate than drivers who drive much less  [16]. Risk groups should therefore be determined not only by age, but also by their annual number of kilometres. 

In addition, the conditions in which older people drive are relatively dangerous. Older drivers, for example, cover a proportionately large number of kilometres on less safe roads. That is, they avoid highways and therefore mainly drive on the underlying road network, where crash risk is higher [11]. Older people do not drive older cars than younger drivers, but they do drive lighter cars more often [17]. A crash study also shows that older drivers are more likely to be in the lighter car in a collision with another passenger car​​​​​​​ [4]. Together with their increased physical vulnerability, this increases the fatality rate of older drivers [4]

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Part of fact sheet

Older road users

From the age of 70, road users have an increased fatality rate as a result of a road crash. The fatality rate for older car drivers (70 or older) is Meer

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