A fatal crash has killed a 27-year-old man and closed the westbound lanes of Highway 401 near the Whitby-Ajax border for much of the morning commute.

The crash happened just before 1:20 a.m. Thursday at Lake Ridge Road. Police say a tractor-trailer rear-ended a car.

The man killed was a passenger in the car. The driver was taken to hospital with minor injuries. The driver of the tractor-trailer was not injured.

All westbound lanes of Highway 401 were closed between Brock and Salem Roads for much of the morning commuting, causing long traffic backups as drivers tried to use alternate routes.

Police re-opened Highway 401 to traffic just after 8:30 a.m.

The province's Special Investigations Unit is investigating because police were in the area at the time of the crash assisting with a road closure.

The SIU is called in any time someone is killed or seriously injured in the presence of police.

There is no word yet on any charges.

The crash in Ajax was one of a handful of traffic problems on what was a difficult morning for GTA commuters.

Winston Churchill Boulevard ramp re-opens after collision

The Winston Churchill Boulevard ramp to Highway 403 has re-opened after a six-vehicle collision on Thursday morning.

One person was sent to hospital after the multiple vehicle crash, which happened after 8 a.m. The left three eastbound lanes were blocked causing traffic congestion. Police, fire and ambulance tended to the scene.

The highway re-opened to traffic after 9:30 a.m.

Truck's bucket gets stuck

Crashes caused problems in other parts of the city on Thursday.

Just after 5:30 a.m. on Highway 403 and Mavis Road an asphalt truck left a construction side with its bucket in the raised position.

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A dump truck's bucket got stuck under the Mavis Road overpass. (Tony Smyth/CBC)

The bucket of the truck became lodged under the Mavis Road overpass and separated from the truck. The driver appeared to have minor injuries. The incident caused traffic delays in the area, closing the two right lanes of Highway 403 at Mavis Road. The Mavis Road southbound ramp to Highway 403 was also closed.

Truck crashes into bank

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A truck crashed into a TD Bank location in Brampton early Thursday. The driver is facing impaired charges. (Tony Smyth/CBC)

In a separate incident, the driver of a work truck is facing impaired charges after hitting a car on Main and Queen Street in Brampton. The truck also took out a planter and smashed through the window of a TD Bank. There were no major injuries.