Old people drive too slow to be a problem . With all due respect, I live here and believe me, on the roads old people are not the ones that worry me. Granted in an ice or snow storm people are going to wreck, but it will effect all ages.
Saw a wreck a couple of years ago, I'm behind an old lady at a stop light, light turns green, she pulls out and gets T-boned by a young guy in a pickup truck. I get out to help, fortunately no one was injured, talked to the guy for a second, he didn't even realize his light was red. BTW one of the things defensive driving teaches you, when the light turns green, make a glance in both directions to make sure no one is running that red light.