The California Highway Patrol says it happened around 6 am Sunday.
The victim was trying to cross Highway 99 in the southbound lanes near the Atwater-Merced Expressway when they were hit by one driver who was unable to avoid the collision.
The pedestrian was then run over by two other vehicles, including a big rig.
Authorities say the drivers were not under the influence and are cooperating with the investigation.
The identity of the pedestrian has not been released.