A chunk of concrete weighing about 10 pounds fell from the Gardiner Expressway onto Lake Shore Boulevard West Monday afternoon, temporarily closing two lanes of traffic just east of Bathurst Street.
No injuries were reported, and city officials said they don't believe any cars were hit by the falling concrete.
Mike Laidlaw, acting manager of structures and expressways for the City of Toronto, said city crews cleaned up the road and checked for more loose pieces of concrete before re-opening the lanes.
He said he doesn't think drivers need to worry about more falling concrete.
"I think our inspection program is fairly good," Mr. Laidlaw said, adding. "We're going to have to step it up to make sure this sort of thing doesn't happen again."
Toronto Councillor Denzil Minnan-Wong, chair of the public works committee, said the city spends about $10-million annually on maintenance for the expressway.
"We are always doing capital repair work and the Gardiner is a real priority because we can't afford to have accidents like this happen," he said.
Mr. Minnan-Wong said city crews will be out again Tuesday to ensure that there is no structural damage to the roadway.