I think that there might be an argument that driving stress would correlate with the necessity of driving. That is, places where it is more stressful to drive have a higher frequency of available public transportation, like in a city, while places that are more relaxing to drive in tend to require having a vehicle for transportation, like rural areas.

Also, there is definitely an element of PTSD that can come with being in a car accident. It can make you jumpy when riding in cars with others or driving. I have heard that many race car drivers end up quitting the sport after a bad accident. No idea how true that is but if you start driving again the jumpiness will eventually turn into a higher level of alertness which can be a good thing when operating a motor vehicle.