Why fuck about, how about compulsory re-testing every n years for everyone?
Whether that's a medical assessment (vision, conditions likely to result in sudden loss of attention/control/consciousness, side-effcts of medications, that sort of thing), or a test of driving skills left as an exercise for the reader.
I know that pilots and train drivers and so on get periodic medical checks, why shouldn't everyone who's licenced to operate dangerous machinery in a public place? Oh wait, roads are *special*.
"Okay, ECG looks fine." *tickybox* "Still diabetic?"
"Of course."
"Having any hypos?"
"Only at night when I've got the lurgy."
"Okay." *tickybox* "Right, let's check your vision..."