A man, who pulled over on the side of northbound U.S. Highway 101 to inspect the source of an odd sound in his car, was struck by a vehicle and killed, California Highway Patrol officials said Sunday.

The collision, which incolved a Mazda SUV and a Ford Ranger, was first reported at 4:14 p.m. just north of Alum Rock Avenue in San Jose, according to CHP spokesman Ross Lee.

The victim's family members, who were traveling with him at the time of the accident, said he thought something was wrong with his car. The Daly City man who is believed to be about 60 years old was hit immediately after stepping out of the vehicle, Lee said.

The driver of the Ford Ranger said he fell asleep at the wheel and sideswiped the stopped car, ramming into the victim, Lee said.

The coroner and two tow trucks have been called to the scene, Lee said.

A traffic alert has been issued for Highway 101 because one lane is blocked. CHP officials do not have an estimate of when the lane will reopen.