Four people have been injured, one of them seriously, after a motorcycle forced their vehicle into a water-filled ditch in south Surrey, B.C.

Police say the vehicle, a Honda CRV, was travelling south on King George Boulevard near 48 Avenue around 1:30 p.m. when it was cut off by a motorcycle travelling in the same direction.

"The Honda attempted to take evasive action to prevent a collision, [but] it overcorrected and went into a water-filled ditch and rolled over, trapping the occupants inside," said Sgt. David MacDonald, with Surrey RCMP.

Children freed by passers-by

Steve Newman was one of several passers-by who stopped to help after seeing the vehicle upside down in the ditch.

"I knew something was up," Newman said. "People are freaking out. They're saying there's kids in the car and there's someone submerged, so I go down to the water."

"There's two guys that are right in the water and they're banging on the window. They're pulling, they're pulling and they're trying to get the people out."

Newman said the ad hoc rescue team was able to free two children from the car before fire and police crews arrived.

All four people were taken to hospital. MacDonald said a 42-year-old woman is in "very serious" condition with life-threatening injuries. The other occupants, an adult male and two preteen children, were treated for minor injuries.

Motorcyclist arrested

Nina Houngbo said the motorcyclist was driving dangerously and cut off several other people — including her — before forcing the CRV into the ditch.

"He cut us off, and then the next thing you know, he cut them off, and then they lost control of their car and [ended] up in the ditch," Houngbo said.

MacDonald said the driver of the motorcycle was later arrested by police, but was unable to provide any details about the driver or what charges they might potentially face.