A collision on Highway 404 at Stouffville Road has killed three people and sent one person to hospital.
Ontario Provincial Police were called to the scene during rush hour Tuesday evening to respond to the scene of a crash.
Reports from York Regional Police indicate a vehicle was travelling south when it crossed the grass median and struck another car in the northbound lanes.
There was debris scattered throughout the roads, causing police to divert northbound traffic to the Elgin Mills Road exit.
All northbound ramps for Stouffville and Elgin Mills roads remained closed after the crash for officials to investigate.
OPP said on Twitter all lanes were reopened shortly after 7 p.m.