VANCOUVER -- The truck driver in a crash that snarled traffic into North Vancouver for hours has been arrested for driving while impaired, local Mounties say.

In a statement, the North Vancouver RCMP detachment said the crash happened shortly after 4 a.m. on Highway 1.

The driver of a semi-truck was heading west, when the vehicle left the highway and struck a "support structure" of the Fern Street overpass.

The man, who has not been publicly identified, is 47 and lives in Surrey, the RCMP said.

He was taken to hospital, but was not seriously injured.

The driver has been arrested for driving while impaired and driving while prohibited, Mounties said. The investigation is ongoing.

The impacted section of highway has since reopened. Westbound lanes were closed for nearly six hours due to the crash at an area police called the "bottom of the cut."

A section from Fern Street toward the Second Narrows/Ironworkers Memorial Bridge was closed off as the crash was investigated and the scene was cleared.

During that time, DriveBC warned commuters to "expect major delays" in the area.

The bridge remained open, but drivers were forced off the Trans-Canada Highway at the exits for Dollarton Highway or Main Street.

The scene was cleared at around 9:30 a.m., but there was a further delay due to a diesel spill, which left a "significant length of highway very slick and dangerous."

The RCMP called in a salt truck, which they expected would take an hour to reach the scene due to traffic. But the truck was able to get there earlier than expected, and the lanes were reopened by 10 a. m.

Photos posted by the RCMP detachment showed a severely damaged vehicle.

Police said the structure of the overpass was damaged, but was inspected before the highway opened to ensure it was safe.