The collision happened on Highway 180 at Blythe Avenue around 1 Monday afternoon.
A man driving a Volkswagen on the highway veered into oncoming traffic -- and slammed into the big rig.
The impact killed the car's driver and officers are now investigating what caused him to lose control.
Neither drugs nor alcohol appear to be factors in this crash.
The driver of the big rig didn't suffer any injuries and remained at the scene with investigators.