A female driver was airlifted to hospital with critical injuries after a wheel flew off a moving vehicle on Highway 400 near Innisfil and smashed through her windshield.

Ontario Provincial Police say that a passenger vehicle was headed northbound on Highway 400 near Highway 89 at around 8:30 a.m. when its front wheel came off its axle, bounced over a concrete median and went straight through the windshield of the woman’s southbound vehicle.

“It went right into the occupant compartment, right at the driver’s position,” Ontario Provincial Police Sgt. Kerry Schmidt told CTV News Barrie at the scene. “When an object comes flying towards you unexpectedly like that there is nothing you can really do to react. It happens in a fraction of a second and by the time you realize it is on a collision course with you there is really no place you can go.”

Schmidt said that the crews are still searching the side of the highway for the wheel that hit the woman’s vehicle and believe that it will be located somewhere north of the scene on the west side of Highway 400.

A Toronto police spokesperson says the vehicle that the wheel came off of was driven by a Toronto police officer returning to his home outside Toronto after work.

The spokesperson said the officer is a member of the Emergency Task Force and he was driving his personal vehicle at the time of the incident.

The officer’s supervisor went to the scene to check on him.

Schmidt said that the wheel could have conceivably travelled a significant distance, given the speed that the northbound vehicle would have been travelling at.

“Why this wheel came off its certainly part of the mystery,” he said. “Was it installed recently? Was it installed improperly? Was it done by professionals or done by the owner of the vehicle? That is all information we are relying to ascertain.”

Schmidt said that the driver of the northbound vehicle could face charges if it is determined that it was not kept in working order.

Several lanes of Highway 400 were initially blocked north of Highway 89, however all lanes of the highway reopened both ways at around noon.