The SUV is believed to have been heading southbound in the northbound lanes of Interstate 5 just south of state Route 163 when it slammed into the pickup just before 2:30 a.m. Tuesday.
The force of the crash was so great that one person was trapped and had to be freed from the wreckage. Several other cars were hit with splintered debris.
All northbound lanes of I-5 were shut down after the crash, with one lane reopening around 3 a.m. The driver of the wrong-way SUV was arrested on suspicion of drunken driving, the CHP said.