An unidentified woman, believed to be in her mid-thirties, is in critical condition with serious head injuries after being struck by a motorist on the Trans-Canada Highway in Coquitlam Tuesday night.

Coquitlam RCMP said the pedestrian and another woman are suspected of shoplifting at a store near the accident, which happened almost underneath the King Edward Street overpass.

Police said a private security guard was watching the two women, and reported the accident to authorities.

An unidentified woman, believed to be in her mid-thirties, is in critical condition after she was struck by a car on the Trans-Canada Highway near the King Edward Street overpass, Tuesday night. (Rafferty Baker/CBC)

Sgt. Tony Farahbakhchian with Coquitlam RCMP said the accident happened at about 9:40 p.m., when the two women were attempting to cross the 10-lane highway.

"These cars are travelling 100-110 [km/h], and she just got hit bang-on," said Farahbakhchian. "She's in pretty bad shape here."

Farahbakhchian said the woman was hit in the westbound fast lane, and the second woman wasn't found, and hasn't contacted police.

The car could be seen at the accident scene with its windshield smashed inward. The car's driver is cooperating with investigators.