A Santa Rosa man was killed Tuesday when a vehicle traveling on Shoreline Highway near the Marin County town of Marshall flipped over and partially submerged in water, the CHP said.

The man's identity was not available Tuesday night. He is believed to have been the driver of the vehicle, CHP Officer Andy Barclay said.

Barclay said two men, both residents of Santa Rosa, were driving north on Shoreline Highway at about 5:30 p.m. when for unknown reasons the vehicle crossed the oncoming lane and flipped over, coming to rest in water.

The highway skirts along Tomales Bay, but it was unclear Tuesday night whether that's where the vehicle ended up. Barclay said the area's remoteness was hindering communications.

He said officers also were working through a language barrier with the crash's surviving victim.

The passenger reportedly was able to get out of the vehicle on his own, while firefighters assisted in retrieving the driver. Both men were transported to Petaluma Valley Hospital.

Barclay said alcohol did not appear to be a factor in the crash.

The vehicle was removed from the water at about 8:20 p.m.