More older drivers are on the road, and an Associated Press review finds a hodgepodge of rules governing what they must do to stay behind the wheel.
Thirty states plus the District of Columbia have some sort of older-age requirements for driver's licenses. They range from more vision testing to making seniors renew their licenses more frequently than younger people.
The ages when they kick in are literally all over the map. Maryland starts eye exams with every renewal at 40. Illinois requires a road test starting at 75. At 85, Texans renew their licenses every two years instead of every six.
Healthy older drivers aren't necessarily less safe than younger ones. But an aging population raises the question: How to tell when it's time to give up the keys?