The collision happened just before 6 am Friday on Avenue 12 at Riverstone Boulevard.
Officers say a Chrysler was heading west on Avenue 12 when it stopped to make a left turn on Riverstone.
For unknown reasons, a big rig behind the vehicle failed to stop and rear-ended the Chrysler.
"The big rig entered the opposite lane and collided head-on with the driver of a white Nissan Altima," says Sergio Moreno with the CHP.
The woman driving the Nissan died at the scene.
The driver of the Chrysler was taken to Community Regional Medical Center for his injuries.
The big rig driver was not injured.