The incident happened near Slauson Avenue around 11:40 p.m. Thursday and only involved one car, according to the California Highway Patrol.
The CHP says the sedan was traveling on southbound lanes when, for reasons unknown, it went through the right shoulder embankment and toward the Slauson on-ramp before it crashed into the freeway sound barrier.
The vehicle caught on fire on impact. When CHP officers arrived on scene, they found four people inside the car that became fully engulfed in flames.
None of the victims have been identified.
Officials are still trying to determine what caused the crash or why the driver seemed to have lost control of the vehicle. They couldn't confirm if racing was involved, but did say speed was a factor.