This has been a topic of discussion in one of my classes at school- whether the elderly (due to normal decline in vision and response times, as well as various pathological processes) should be allowed to continue to drive. The reason behind this is on of the public safety golf carts on campus was struck by an elderly driver (luckily no one was hurt in the low-speed collision), who claimed that he did not see the BRIGHT WHITE golf cart with the FLASHING AMBER LIGHT on top of it in the intersection which is marked with two large "PEDESTRIAN CROSSING" signs, each with a FLASHING CAUTION LIGHT. This happened in the middle of the day, but this elderly gentleman apparently didn't realize they were there until he heard the "THUD" of the collision.
I recall reading somewhere that while teenagers are more likely to kill themselves, or people in the same vehicle with them, that the elderly kill nearly as many people, most often pedestrians and persons in other vehicles. I'll try to find the article to back this up.
Should people have their licenses restricted or revoked upon reaching a certain age? Should more frequent health checkups (vision tests specifically) be required? Should special exemption to continue to drive past the age of 65 be required?
And, yes, I know this type of legislation would never get passed because of the legislative clout of organizations such as the AARP.