The Malahat was shut down for three hours during the Monday morning commute after falling rocks struck a vehicle on the Vancouver Island highway.

Police say at least one vehicle was struck after the rocks fell near Tunnel Hill just before 8:30 a.m., but the driver is believed to be unhurt.

"He's a little bit rattled from when it happened, driving to work and a boulder comes shooting across from the southbound lane into the northbound lane," said Dave LeQuesne of Westshore Towing, who was among those responding to the incident. "This could have had a significant impact if it ended up differently."

Geotechnical engineers were dispatched to the highway to assess the rock wall boulders fell from. A photo of the scene tweeted by Transportation BC shows a large rock near a barrier, and another barrier with a large chunk missing.

Northbound lanes reopened just after 11 a.m., with southbound lanes opening at around 11:30 a.m. Delays were still expected after the highway reopened due to congestion that built up on either side of the Malahat Summit, according to Drive BC.

LeQuesne said though the slide was small, crews had to take necessary precations before the highway was reopened.

"It's not a large slide, it's two rocks. One rock actually split into two. But it's what's happened to cause this and the liability, it needs to be checked out," he said. "If the ministry was to just open up the highway and let people travel and something was to happen, it would be a huge liability case."

BC Ferries said it did not have a replacement crew for the Mill Bay-Brentwood Bay route that bypasses the Malahat. In previous crashes, the ferry quickly filled up with commuters trying to skirt closures.

The incident was the latest to shut down the major route, effectively cutting off the Greater Victoria area from the rest of the island. It's the second time in the last three weeks that the Malahat has been closed entirely.

A fatal crash involving a sewage truck on Aug. 22 shut down the route for about eight hours, prompting new calls for an alternative to the route.