I think that helping remind older folk about falling into Bad Habit driving is the best way to improve their skills as well as potentially assess their driving overall. IF and only IF their driving is so low standard further investigation is needed to assess if medical (eyesight) or old age (brain function) is the root cause.
It is useless if you force old folk into expensive assessments when it is totally un-necessary, and if I get old then I don't want to have to face a whole load of test and proving exams. I just want to have someone tell me the truth and try and improve and if still unsuitable then one has to face the end of one's driving career, which I would hate. Imagine if you are by yourself and this is your only way to travel, it deprives them of their freedom, so first we have to be obligated to understand what and why things are going wrong.
More skills, knowledge development earlier on may help to prevent the onset of bad behaviours later.
Then IF a car is suitable for the elderly drivers to enable them to have their freedom, and so OK they are in slower perhaps electric vehicles.
I would that they traveled at 40mph comfortably (and told to pull over often) in a 60mph with an 'OAP' badge, (and I overtake them) (IF they are otherwise competent), than to run them off the road - as it were.
I hate tests and might perform badly, assessments over time are better and more realistic.
On another note I have found that placing lots of batteries in a Corsa does help it to vibrate less and be a little more stable !
I agree in general that tidy cars, may typically mean that someone cares about the car, and might also extend into their driving, but I am not totally convinced. I absolutely agree that secure luggage is best practice, and shows a level of driving concern.
However I have, as some of you know, had one heck of a lot to deal with, and my cars have fallen way below my normal 'standard' as a consequence, which I find very sad. I do find it hard to have animals and a clean car or at least a non hairy one, and try hard to keep things very organised ! The roof box is good for some long laden journeys.