The road safety of elderly road users is to a large extent determined by two factors: functional limitations and physical vulnerability. Both factors contribute to the relatively high fatality rate among elderly road users in crashes. Taking the distances travelled into account, the fatality rate of the over-75s is about eleven times higher per kilometre travelled than the average fatality rate for all ages. The fatality rate of the 60-74 year olds is much lower (see Table 1). The fatality rate for cyclists is also considerably higher than average, even for the younger elderly. The main reason for this is their increased physical vulnerability combined with the lack of protection offered by the vehicle (see also the archived SWOV Fact sheet Senior cyclists).
According to some researchers their low annual mileage is part of the explanation for the high fatality rate for elderly car drivers. It may be argued that drivers wit a high annual mileage generally have a lower crash rate than drivers with a low annual mileage. These researchers therefore argue that if risk groups were not only determined based on age but also on annual mileage, the crash rate of elderly drivers with a low annual mileage would not be higher than that of younger drivers with an equally low annual mileage. Furthermore, the crash rate of elderly drivers may be overestimated because they travel a larger share of their kilometres on roads with a lower safety level. The elderly tend to avoid motorways and therefore mainly use the secondary road network which has a higher crash rate (Davidse, 2007; DaCoTa, 2012).
Table 1. Death rate by age group and transport mode: real number of road deaths per billion kilometres travelled, 2011-2014. (Sources: Statistics Netherlands, Ministry of Infrastructure and the Environment).
Functional limitations
As people age, functional limitations and disorders occur, such as reduced visual or auditory abilities, increased reaction times, difficulties with dividing attention, and dementia. The decline of motor functions in particular can increase the crash rate. In general terms, this decline consists of a slowing down of movements, a decline in muscle strength, a decline in the finely tuned coordination, and a particularly strong decline in the ability to adapt to sudden changes in bodily position. This last aspect is especially important for cyclists and pedestrians, but also for those who use public transport (walking and standing in moving buses and trains).
There are few indications that a decline in visual, auditory and cognitive functions, as part of normal ageing, also has road safety consequences. Only in the case of severe sensory, perceptual, and cognitive limitations does the relation between functional limitations and crash involvement become visible (Brouwer & Davidse, 2002; Davidse, 2007).
Physical vulnerability
The elderly are physically more vulnerable than younger adults: their injuries will be severer given an identical collision impact. To illustrate this: with the same impact force, the fatality rate is approximately three times higher for a 75 year-old motor vehicle occupant than for an 18 year-old. The physical vulnerability has the severest consequences during travel by 'unprotected' modes of transport such as walking and cycling. This physical vulnerability is a less important factor for drivers, but it still has an influence on injury severity. Protection devices such as helmets for cyclists and (light-)moped riders, and seat-belts and (side) airbags for drivers, can limit injury severity.
