A 14-year-old boy was killed by a pickup truck late Tuesday as he tried to flag down help in the middle of Interstate 5, officials said.
Authorities are still searching for the driver of the dark-colored truck, which was pulling a trailer.
The boy was riding with his uncle in a 1996 Dodge minivan when the vehicle broke down in a center lane of the Golden State Freeway south of California 14 near Sylmar.
Just after 10 p.m., the teenager jumped out of the vehicle to get assistance, Officer John Lutz of the California Highway Patrol said.
The boy's uncle, Alejandro E. Rios, 33, of Santa Paula, tried to order the boy back into the vehicle, Lutz said.