A 27-year-old man is dead after a two-vehicle crash on Highway 401 near Ajax.

According to Ontario Provincial Police, a tractor-trailer was travelling westbound on the highway at around 1:20 a.m. when it struck the rear of a vehicle near Lakeridge Road.

The driver of that vehicle was taken to hospital with unknown injuries and the 27-year-old passenger was pronounced dead at the scene.

The driver of the tractor-trailer was unharmed.

The province’s Special Investigations Unit has been called in as Ontario Provincial Police were slowing traffic in the area at the time of the accident.

The SIU is an arm’s length agency called in whenever police are involved in an incident that results in a death or serious injury.

All westbound lanes were closed between Brock Street and Salem Road, but the highway reopened at around 8:30 a.m.

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