Age alone doesn't make someone an unsafe driver. Health and ability are needed for safe driving.
Abilities needed to drive safely include:
Vision, to see other vehicles, traffic signals, signs, lane markings, road conditions, bicyclists and pedestrians
Memory and judgment, to recognize locations, remember rules of the road, understand information and react appropriately
Strength and flexibility, to steer the vehicles, turn the head to check for traffic, use the seat belt and push down the pedals
With age, people might experience changes in their health or abilities. Many older drivers choose to change how they drive, for example by not driving at night.
Health conditions or medications can make driving more difficult. Medical causes of driving concerns can be treatable or correctable. Health professionals can help determine what's causing driving problems.
People with memory or judgment problems, including dementia, might not recognize if their driving has changed or become unsafe. Family, friends, health professionals or others might need to get involved.
A single incident doesn't make someone an unsafe driver. Multiple incidents, especially if they become more frequent or dangerous over time, can be warning signs of serious problems.