Driving means manipulating a dangerous piece of machinery at speeds beyond anything for which evolution has prepared you, reacting to a multitude of visual signals and warnings, calibrating and recalibrating velocity, distance, direction and stability, all the time guessing the intentions and anticipating the possible actions of unnumbered others performing the same tasks in the same places at the same times. And this while talking, listening, daydreaming, trying to work out where you are and where you should be. Yet we know that as we get older we get worse at most things. Surely age affects this too?
It does, but the relationship is not as straightforward as it is in the golf performance of a friend of mine who makes himself miserable by measuring his age-related decline in terms of how far he can hit the ball. Driving, and most measurements of it, is more complicated (though not necessarily more demanding) than golf. We should keep pointing this out because every so often there are government mutterings about restricting older drivers — which means all of us, eventually.
Age-related accident statistics generally show a U-shaped pattern, with the under-25s at highest risk, a decrease through middle age, then an increase in old age — although even octogenarians have only a fraction of the number of accidents sustained by the young. But concealed within most studies are complicating factors and reporting bias. Frailty, for instance, means that the physical consequences of accidents are often more severe for the elderly, which in turn means that their accidents are more likely to be reported and so enter the statistics. Therefore, the old could be over- represented in accident figures. On the other hand, such figures usually do not take into account the numbers of drivers in each age category nor the mileage driven. Since older people tend to drive less, avoid busy periods, stay in familiar territory and drive mostly in daylight, it could mean that, proportionally, they’re under-represented.
But on yet another hand, while comparisons between low- and high-mileage drivers tend to show a greater accident rate among the former, it is also the case that most high-milers do their driving on motorways, which are safer than ordinary roads because everyone’s going in the same direction. So perhaps they’re not under-represented after all.
There is, however, a clearer distinction between kinds of accident. Younger drivers tend to have more accidents attributed to speed and loss of control, older drivers more often have accidents at junctions through misjudging the speeds of oncoming vehicles. Thus, you’re more likely to be hit by a younger driver and more likely to hit an older one. Overall, when all the variables are taken into account, age does not by itself seem to be a reliable predictor of accidents; nor, surprisingly, does visual impairment. (If you doubt this and feel statistically robust, read Graham Hole’s The Psychology of Driving, Lawrence Erlbaum Associates.)
But you don’t meet many 80-year-old fighter-pilots. Where motor skills are concerned, the young do everything better except, arguably, recognise their limitations. This is not just a question of reading the road ahead or not putting yourself in the way of trouble in the first place, but learning self-control, not reacting to stupid challenges, avoiding your weak areas, adapting and compensating.
Freedom of movement is an implicit threat to governments and they love reasons to inhibit it. Age is a convenient statistical category but the truth, where driving is concerned, is inconveniently mixed. The old are us — or will be, sooner than you think — and those with breath to do so should speak up for them now.