In pre-med studies, areas of the brain are mapped to determine the location of certain skills and knowledge.
I submit (she said in her best Captain Kirk voice) that the location of driving knowledge is in the pigmentation of the hair.
Consider if you will that young people, with a full head of luxuriant hair, know everything there is to know about driving. They flit in and around traffic with impunity.
Yet eventually the gray creeps in, and the ability to drive properly creeps out. Salt-and-pepper drivers are sloppy and poorly coordinated. By the time the hair is all white, the Q-tips (my daughter’s euphemism for little old white-haired men) are cutting you off and wandering all over the lane.
Dyeing one’s hair is simply artificial intelligence – his/her inability to drive well belies him/her.
Recently President Obama was in a driving simulator. He commented that he’s rusty since he hasn’t driven in a while. I comment – notice that he is simultaneously turning gray, as all presidents in office do. This is probably why they continue to use limousine services after leaving office.
Rich old men are wise enough, once their flowing locks turn white, to depend on limousine drivers as well (whom, you will notice, have fully-pigmented hair).
The challenge is baldness. Unless the person has a skirt of hair around the nape of the neck or facial hair, it behooves other drivers to watch carefully to determine the extent of driving knowledge which has been retained or lost.