The coroner has identified the victim as 82-year-old Louis Schaefer. The CHP believes a large brass bolt went flying through the windshield of his minivan.
"While searching the vehicle, officers found a brass, sort of like a plumbing material, like a nut, approximately the size of a baseball," said CHP Officer Art Montiel.
Schaefer was driving north on Highway 101 through Palo Alto around 1 p.m. when a large projectile slammed through his windshield and hit him in the neck.
His van went off the highway and careened along the center divider before coming to a stop. Other drivers pulled over and tried to help him, but it was too late. First responders pronounced him dead at the scene.
Investigators are asking witnesses to come forward in the hopes that they can shed more light on exactly what happened.
"To see if, you know, maybe this fell off another vehicle," said Montiel. "Or maybe it was kicked up, got kicked up by somebody else's tires as they were driving by."
It was an unusual and terrible accident that cost an innocent driver his life.
"That's very tragic, there was probably nothing he could have done to avoid that," said Montiel.
Two northbound lanes were closed for two hours while the CHP investigated and cleared the scene.
Coroner has ID'd the man killed by a projectile on NB101 as 82 year old Louis Schaefer of #MountainView.— Katie Marzullo (@KatieABC7) September 17, 2016
It's not yet confirmed. It appears this may have been the projectile that may have been kicked by passing traffic. pic.twitter.com/lyjGadKvr0— CHP RWC (@CHP_RedwoodCity) September 17, 2016
.@CHP_RedwoodCity says projectile that killed an elderly driver on NB101 was a large brass bolt.— Katie Marzullo (@KatieABC7) September 16, 2016