15 migrants died after the SUV they were passengers in collided with a semi truck on Tuesday, around 6:15 AM local time near the California-Mexico border.
The highway patrol said the Ford Expedition, designed to carry six people, was packed with 27 migrants when it entered a busy intersection where it collided with a gravel-filled semitruck.
Fourteen people, including the Ford driver, were pronounced dead at the scene, and another passenger died at a hospital, officials said.
California Highway Patrol Border Division Chief Omar Watson said the SUV had no seats other than the driver's seat and front passenger's seat.
Watson did not indicate whether the migrants had just entered the country.
He said several of the passengers were ejected from the vehicle and died upon impact.
"Everyone in the vehicle was injured to some extent," Watson told reporters.
"Obviously, that vehicle is not meant for that many people," he added.
Watson said the SUV's driver may have ran the stop sign. "Subsequently the big rig collided with the left side of the Ford Expedition."
No charges have been filed in the crash.