UPDATE (Jan. 5 -- 8:21 a.m.) According to Bryan Moore of California Highway Patrol, Fort Tejon, around 5 a.m. an unknown big rig dropped a metal object from his truck and kept driving. CHP thinks the driver may not have known the item fell off the vehicle.

Another big rig driving on southbound I-5, near Gorman School Road struck the metal item on the roadway and hit a pickup truck that was carrying a trailer. That trailer overturned in the roadway and was carrying two previously wrecked cars that spilled onto the road.

However, only two vehicles were involved in the initial crash.

The driver of the pickup truck suffered minor injuries and was transported to Henry Mayo Newhall Hospital. 

Traffic at the time of the accident was backed up past Frazier Mountain Park Road. All lanes opened up around 7 a.m.