Actress Reese Witherspoon was struck by an 84-year-old woman driver while she was jogging across the street. The elderly driver claimed that her view of the intersection was obstructed by a large tree. Reese is said to have suffered minor injuries and is resting at home.

Los Angeles police cited the woman driver for failing to yield to a pedestrian in a crosswalk. Similar incidents can happen to any driver but when it involves an older driver, questions may spark about whether it is time to give up the car keys or at least begin a discussion about it.

A person younger than 22 tends to have more accidents, and that number increases again starting at ages 65 to 75, says David Melton, managing director of Global Transportation Safety at Liberty Mutual Insurance as reported by MSNBC.

"Everybody ages differently, and I include myself in this because I just celebrated my 65th birthday, and I've already had this conversation with my wife and son and told them if I start to show reluctance to drive at busy times, in bad weather, if I don't want to drive on freeways or if there are more dings in my car than there used to be, those are indicators."

University of Rochester in a study released last January said that older people have trouble driving because they have less focus on what is right in front of them. Their attention seems to be diverted to the people and cars moving around them.

National Highway Traffic Safety Administration also mentioned that crash risks when trying to navigate with more complex road situation appears to increase with drivers over 80 years old.

The American Automobile Association estimates 37 million drivers will be 65 and older by 2020, and 90 percent of them will be licensed. Drivers aged 85 and older has surpassed 3 million.

"There's no magic age when people become unsafe on the road. Older drivers are relatively safe. Usually, it's an underlying health issue that causes people to have accidents," according to veteran gerontologist Jodie Oshezki with the Hartford Insurance company.

In a country predominantly dependent on automobiles, a senior giving up car keys may mean relinquishing independence. Giving up driving may be synonymous to social isolation.

Kaarin Anstey, a psychologist at Australian National University and lead author of report using a novel method to gauge how people drive published in the journal Neuropsychology, mentioned that the most common mistake committed was not checking the car's blind spots, followed by problems in changing lanes or failure to use directional signals. Both sexes performed equally well or badly according to an article last May in the New Old Age blog in NY Times.

Despite these findings, Dr. Anstey doesn't endorse restricted driving privileges based on age alone.

"We believe driving should be based on actual functional capacity," she said. She further thinks that her findings could be used to develop programs that would retrain seniors to drive. "I don't see why we couldn't train people to check the blind spots," she said. Furthermore, additional safety measures could be implemented to address specific lapses, "We can also put in extra blind-spot mirrors to improve visibility."