Pieces of concrete fell off the Gardiner Expressway before rush hour Wednesday morning.
There have been no reports of injury or damage.
The pieces fell onto Bathurst Street, which resulted in a road closure between Lake Shore Boulevard and Fort York Boulevard.
There are also no 511 Bathurst streetcars between Queen Street and Exhibition Loop.
This is not the first time the elevated expressway has had reports of falling concrete.
On June 25 pieces fell onto a car while a man was driving to work. The driver was not injured, but after that incident, Toronto staff briefed a council committee on the state of the Gardiner, which they said is in need of significant rehabilitation in the next 10 years.