LIVERMORE — California Highway Patrol investigators are hoping witnesses will come forward after a Sacramento-area man was impaled by a metal pipe that came crashing through his car windshield as he drove on Interstate 580 Wednesday morning.

Officials say 33-year-old Michael Cox, of Rocklin, was driving westbound on the freeway near Livermore around 8 a.m. when the pipe — an inch or 2 in diameter and 2 or 3 feet long — apparently fell off a truck, went thought the windshield and penetrated his upper body area.

After the incident Cox's car crashed into an embankment. When emergency crews arrived, they pronounced him dead at the scene.

CHP investigators say since the pipe had no markings or company name, they don't think they'll be able to find the vehicle unless a witness comes forward.