I was trained to drive to P1 level in the Ambulance Service. I am fully aware of my shortcomings as a driver and try to avoid mistakes. I don't claim to be perfect, but am aware of of hazards and drive in a way that is defensive. I do drive quickly when it is safe, but when it is not, then I do not. I try not to break speed limits, even on a quiet motorway at night; it may be within your capabilities when everything is OK, but when something goes wrong at speed, it goes wrong very quickly and while you may escape a blowout at 70, your chances decrease significantly at 90 and when you do hit something, the results are more serious by a large margin.
The difference with someone not trained to this standard is that you often find, they claim to be better drivers than they actually are, those who are trained to this standard accept they are still developing their skills and are regularly sent for refresher training.