They say at least one vehicle was badly damaged as concrete broke through the roof and landed on the front passenger seat.
"When people are throwing not just bricks, but full cinder block pieces of cement off of an overpass onto traffic below the results can be deadly and also catastrophic", Schmidt said.
On Wednesday, another cement cinderblock was thrown onto the same highway from the Yonge Street overpass at around 11:15 a.m., according to Ontario Provincial Police Sgt. Kerry Schmidt.
The driver, although shaken up, was not physically injured.
Witnesses said the suspect from the Yonge Street incident was a man, but OPP says there is no information available on a suspect for the other two instances.
An hour later, a second incident was reported at the Warden overpass.
"My thanks to the public and to the media for bringing this matter to a very quick end", said Schmidt. A witness had seen suspicious activity on an overpass along the highway and took photos of the person and vehicle involved.
The man is due for a bail hearing Thursday morning at Toronto's Old City Hall.
The suspect, whose name has not been released, faces three counts of mischief endangering life.