Reaction times correlate with lifespan and with intelligence. In evolutionary terms this makes sense: quick reactions allow you to spot dangers, avoid predators and live another day.
In contemporary life, which is now very safe, one of the few causes of premature death are traffic accidents. Motorbikes are the worst. Without a protective cage to absorb impact, riders cannot survive. Helmets don’t help much because necks break as easily as skulls. Pushbikes don’t mix well with motor traffic. All cyclist deaths are premature and preventable, if only by taking public transport, which is safe. Cars are now safe for their occupants. Car braking systems very rarely fail. Human drivers fail every so often. Young over-confident incompetents are the worst, as are drunks of all ages, but careless idiots still cause injury, and each of us will be a careless idiot at some time in our driving lives.
Here is a reaction time test which is a better measure of attention while driving. Unlike the “BBC poisoned arrow sheep” and the various traffic light tests it has face validity, because it lasts for 5 minutes, which simulates the real life requirement of sustained attention. Of course, 5 minutes is not very long, and half an hour would be more realistic. The simulation is also unrealistic in that the hazards happen frequently, whereas in real life they happen rarely, with long boring bits in between. Furthermore, in this test one can begin to anticipate when it is time for the next hazard to show up. The results give the average time of response, but merely record the number of crashes and “false starts” without any further comment. The site constructors have a particular emphasis on fatigue caused by lack of sleep, which is certainly a factor when lorry drivers are sleep deprived, but probably not such a big issue with ordinary car drivers.
My own results “need to be seen in context” (were bad). On the first trial I hadn’t properly understood the instructions. After each hazard the reaction time comes up, which is distracting, but is probably a good example of the many distractions while driving. My average reaction time was 0.31 with one accident and 4 false starts. In other words, death. After a brief pause I tried to redeem myself. Second trial: average reaction time 0.32 with o accidents, 0 false starts. Clear evidence of learning in a dead person.
Let me know how you get on.