Object that flew through driver's windshield on Hwy. 1 believed to be 'large rock'

Police investigating a single-vehicle collision that sent a driver to hospital in critical condition and trapped traffic on Highway 1 for hours Thursday say they've recovered an object in connection to the crash.

The incident happened at about 11:30 a.m., with police explaining at the time that an "unknown object" went through the windshield of a white sedan, seriously injuring a driver.

On Friday, investigators said they'd found "a large rock," approximately the size of a volleyball, in connection to the crash. While the collision happened near the Willingdon Avenue exit, investigators said there's no indication the rock came from an overpass.

"The rock would appear to have come from a passing vehicle and it is unknown at this time what kind of vehicle," Cpl. Melissa Jongema told CTV News Vancouver in an emailed statement.

As a result of the incident, westbound lanes on Highway 1 between Willingdon Avenue and Gilmore Avenue Diversion in Burnaby were temporarily closed on Thursday and drivers were warned to expect major delays.

A highway on-ramp was briefly used as an off-ramp for vehicles that were stuck on the highway and the route fully reopened shortly before 6 p.m.

Police said they're still investigating the crash, adding they're collecting witness information and dash-cam video.

As of Friday afternoon, the driver remained in critical condition.

With files from CTV News Vancouver's Spencer Harwood