Agree with Sh4rkybloke.
Told before here - had this problem years and years ago with my dad. His driving became appalling and he had completely lost accurate judgement of speed. It was getting to the point where he was frequently nearly losing it on corners by taking them too fast. The family convinced him to give up driving, but he and the family got serious grief from my mother (selfish b*t*h) who wailed and ranted long and loud about how no-one was thinking of her, how would she get her shopping done? How she'd be trapped in the house... even asking her how she would feel if Dad injured or killed himself or some innocent third party was nothing to her. Oh, and there was a bus stop with a bus the few miles into town every 30 minutes a couple of hundred yards from the front door of the house.. She made my Dad's life hell when he did give up. She never forgave him for that even though she found she didn't have to rely on his driving after all, and in a way, she got more freedom as she could go out without him having to drive. All sorts of things go on in folks' minds when it comes to the issue of giving up driving.
Living where I do now, in rural parts, where public transport is almost non-existant, the issue of the elderly being isolated in their homes is a very real one. Lots of people drive when they really shouldn't. IMO, down to the lack of a practical alternative being available.