GOTSU, Japan — Before Atsumu Yoshioka, 81, decided to give up driving, there were signs it might be time.

During a visit to a shrine in rural Shimane Prefecture in western Japan, Mr. Yoshioka, a retired furniture maker, forgot to set the parking brake, spooking his wife, Kazuko, when the car drifted backward.

Then one morning as he backed out of the driveway, he rammed into a large urn in front of their home. Haunted by television news reports of fatal accidents caused by older drivers, Mr. Yoshioka called it quits.

“Before I caused any serious accidents,” he said, “I decided to give up driving.”

As Japan’s population ages, so do its drivers. Japan has the oldest population in the world, with nearly 28 percent of its residents above 65 years old. One in seven people are over 75. In the United States, by comparison, that figure is closer to one in 16.