One westbound lane of the 401 is now open between Marysville Road and Deseronto Road, after a crash involving two transport trucks this morning.
Police are asking motorists to continue to be patient, as alternate routes are still being used to assist with traffic movement through the area as vehicles are still being removed from the scene.
It happened around 10:00 a.m., with at least one person being airlifted to hospital by an Ornge air ambulance.
No other information on injuries has been released.
