My wife's grandfather was killed when he pulled out in front of someone. He passed instantly. Grandma had to be extracted out from under the dash. It was generally agreed that he should not have been driving anymore, sadly he was the family patriarch, an old school Mennonite preacher and didn't want anyone telling him what to do.
My wife has told me that she took a ride with him a few months before that and she was scared to get in the car with him behind the wheel.
I've read that the AARP campaigns against testing for senior citizens, claiming that it infringes on their rights.
One things for sure, when I see a gold Buick Lesabre with a grey head looking over the wheel I stay the hell away.