Five separate collisions on Highway 401 created major congestion for commuters Thursday.

The crashes, all involving tractor-trailers, stretched from Milton to Port hope along Canada’s busiest highway. No serious injuries were reported in the collisions.

In Toronto, Police closed the eastbound express lanes for almost two hours near Leslie St. due to a three-tractor trailer crash.

Further east, Highway 401’s eastbound lanes were blocked for several hours just west of Port Hope.

In that incident, which happened just after 6:30 a.m., a trucker who police say was blinded by the rising morning sun rear-ended a truck that was towing carnival equipment. Another truck tried to avoid the collision and lost its load in the south ditch.

Police say another tractor-trailer plowed through the scene, causing another collision down the road. That incident involved a pick-up truck towing a trailer.

Later, a tractor-trailer trying to take a detour under a bridge jackknifed on Lakeshore Road, creating even more traffic congestion west of Port Hope, OPP said.

West of the GTA, a crash involving a tractor-trailer on Highway 401 near Guelph Line also slowed traffic around 8:30 a.m.

Just after the noon hour, a dump truck left the westbound 401 west of Brock St. in Whitby and plowed through a separating wall before coming to a stop in a field near a subdivision.

Local resident Reg Munro said the area where the truck stopped is a popular area for people walking their dogs.

Luckily, no one was there at the time.

“Imagine walking your dog and all of a sudden this truck comes barreling at you,” he said. “You’d never expect it with a wall like that.”

The driver was taken to hospital but is expected to be OK.

With a report from CTV Toronto’s Tamara Cherry and with files from CP24's Chris Kitching