“Even when race car drivers leave the mayhem of the track, their skill doesn’t outweigh their appetite for risk: a study from the 1970s found that racing drivers from the Sports Car Club of America had a higher crash rate on public roads than other drivers from the same state of the same age and sex.”
Compare that to this:
“At the opposite end of the spectrum are those who use cautious driving styles to make up for their weak skills. Some elderly drivers who score poorly on a driving test nevertheless manage to drive crash-free by actively compensating for their deteriorating abilities, according to a Belgian study from 2000. They drive more slowly and avoid tailgating, leaving long safety gaps behind vehicles they’re following; they also plan their trips to avoid complex traffic or other challenging situations.”
Of course, this has implications for self-driving technology:
“Some of the more dramatic estimates have imagined quintupling the volume of traffic flowing down a road. But a short “headway” — the gap between one vehicle and the one just ahead — brings a higher crash risk than a long headway.”
Supposedly the reason the Google Self-Driving Car Project kept its vehicles tooling around Mountain View at 25mph for years is that a collision at 25mph results in something like a 20% chance of a human fatality. At 45mph, the likelihood of fatality flips, and becomes something like 80%. A 2015 report hints at this, although it is more vague about the statistics.