There are major back-ups Tuesday morning on Highway 401 and Highway 3, due to a tractor-trailer collision.

Emergency crews are on the scene where a tractor-trailer jackknifed on Highway 3, east of Howard Avenue. Police expect Highway 3 eastbound and westbound lanes to remain closed for two hours.

Traffic from Highway 401 is being diverted onto Walker Road.

OPP is asking motorists to find alternative routes and avoid the area if possible.