A 36-year-old man was charged with careless driving after a cattle truck he was driving overturned, leaving cows roaming loose on one of Toronto’s busiest highways.

Travellers driving on Hwy. 401 near Mississauga, Ont. met some unexpected traffic after more than a dozen cows were released, following an accident involving a cattle carrier on Friday.

The crash happened at about 11:30 pm when the cattle truck driver hit a guard rail in the westbound lanes approaching Hurontario Street, Ontario Provincial Police Sergeant Kerry Schmidt said.

The collision split the side of the truck, allowing a number of cows to wander away from the crash site.

Twelve cows were found dead in the trailer as a result of the collision, police said.

Mount Forest, Ont. resident George Scott was charged with careless driving following the incident. Scott sustained minor injuries from the collision, according to police.

Both the express and collector’s lanes had to be closed for nearly two hours as the cows roamed the highway. The full highway didn’t reopen until 6 a.m. Saturday when OPP and Mississauga firefighters were able to corral the cattle.

Peel Paramedics said on Twitter they were on scene to treat and transport a patient with moderate injuries from the collision.