UPDATE: Both lanes have now re-opened to traffic
Police say one person is believed to have suffered life-threatening injuries after an S-U-V was hit by a flying truck tire on Highway 400.
It happened between King Road and Aurora Road.
O-P-P Sergeant Kerry Schmidt says the tire flew off of a tractor trailer travelling on the southbound lanes of Highway 400 this morning and bounced into the northbound lanes hitting the vehicle.
A male driver is listed as critical after being airlifted to a Toronto trauma centre.
A police collision reconstruction team is on scene for the investigation.