TORONTO - It's up to seniors and their doctors to decide when it's time to stop driving, not the government, Premier Dalton McGuinty said Wednesday.

"For some folks, it's sooner rather than later, but there does come a point in time when it is no longer safe for you to drive a car," he said.

"You have to be honest with yourself in that regard ... and so does your physician."

McGuinty's comments came a day after a Toronto mother was killed when she and her baby were hit by a car that ran a red light. The 12-week-old boy was unharmed despite being knocked out of his stroller.

The driver was a woman in her 80s, according to police.

McGuinty said he's willing to listen to any advice Transportation Minister Jim Bradley may offer, but he doesn't believe the accident is "something that calls for actions on the part of government."

"But it does call for, I think, careful consideration by our seniors and by their doctors," he added.

Ontario has the "toughest regime" in Canada for senior drivers, Bradley said.

When drivers turn 80, they must pass a written test and attend a class with other drivers. If the driver has any demerit points, they must pass a road test, he said.

Drivers over the age of 70 who cause an accident are required to undergo a re-test. Any medical problems must also be reported to the ministry by law, and the driver's licence is suspended until those problems are overcome, he added.

"We get most of our complaints from senior drivers who think it's very onerous," he said.