I agree with much of grandad's post, particularly the first two paragraphs, the state of one's health is of course crucial and as we age there can be a huge disparity between those who are still physically fit and their reactions and awareness still up to scratch. It's fair to say that young, males particularly, can be a lot more reckless.
My late parents both gave up driving before they died, my father in his late 70s who had type 1 diabetes and increasingly suffered hypos, decided he wasn't as safe as he should be at that stage. My mother, never that keen on driving in the first place, took taxis on her short journeys or more often than not got a lift from friends after he died.
My father in law took my mother in law's car away when he rightly felt she was becoming a danger due to the onset of dementia, frequently getting lost. He drove into his early nineties but also gave up for the last couple of years of his life.
I'd like to think I'd do the right thing if I become really old and my reactions became impaired.
I read about the little boy, how awful, and to have that on your conscience in the last years of life 