The two-vehicle collision was reported shortly before 2:30 a.m. near Mountain Avenue, according to the California Highway Patrol. The deceased individual was not immediately identified.
The closure of the westbound side of the freeway lasted for about three hours, until two lanes were reopened. Traffic remain snarled as the morning commute got underway.
All lanes were reopened shortly after 7 a.m., Caltrans said.
The cause of the crash is under investigation.