One easy way to start would be to give basic reflex and reaction tests. On one of my last trips to the supermarket early this year before the COVID lockdowns started, I was on line behind a very elderly old woman (who for some reason had chosen the self-checkout line). She had trouble merely attempting to lift her groceries out of her basket and scan them. She was entirely unable to feed her bills into the feeder without assistance. As I was leaving the supermarket I watched her struggle to open her car door before slowly getting into her car. I sat in my car for a few minutes watching as she struggled mightily to simply back her car out of her parking spot.

Here in New York, the roads are filled with elderly people like this. Mental acuity aside, they do not possess anywhere near the reflexes or dexterity to drive a car safely. Nonetheless, they are out there on the roads every day. It would be a trivial issue to implement basic physical and mental acuity tests that should be required in order to have a driver's license. Unfortunately this remains implausible because of the lack of an alternative means of transportation available to these elderly people (which could potentially be provided by self-driving vehicles).