What can you do with an elderly person who shouldn't be driving and will not give it up?

85 yrs old, still driving. Will NOT quit driving. She says all her friends and worse off than she is and they all tell her that she is a very good driver.
She has trouble seeing, drives over curbs, drives too fast and sees NOTHING but what is directly in front of her. She lives in Ohio, I can't seem to find anyone that can do anything about this. All family members have told her it's time to quit. She will not have anything to do with it. I'm almost at the point of calling the police and having them tail her. She has been lucky so far. No police stops. No accidents. Suggestions?