A man suffered major injuries Monday when his car flipped on southbound Highway 101 on the Cotati Grade, fire officials said.

Shortly after the 8:11 p.m. crash south of West Sierra Avenue, a woman and child showed up at Petaluma Valley Hospital with injuries apparently caused in the crash, dispatchers said.

Rancho Adobe Fire Capt. Michael Weihman said a passing motorist possibly took them to the hospital.

The driver was trapped and unconscious when Rohnert Park firefighters arrived at 8:20 p.m., Weihman said. The car was on its roof in the right-hand lane.

The four-door sedan was heavily damaged and lost a wheel in the crash. Firefighters cut off a door and through other parts of the car to free the man, Weihman said.

The man was taken with possibly life-threatening injuries to Santa Rosa Memorial Hospital.

The conditions of the woman and child were unavailable Monday night.