OCEANSIDE, Calif. (KGTV) — Three people were killed on Thursday after an SUV careened off State Route 78 and crashed into a traffic signal pole.

A Mitsubishi Outlander was traveling on westbound SR-78 at about 2 p.m. when for unknown reasons it veered off the right side of the freeway near El Camino Real and went down an embankment. The SUV hit a fence and struck a pole at the intersection of Vista Way and Valley Glen Dr., before catching fire, according to CHP public-affairs Officer Mark Latulippe.

CHP officers arrived within minutes to find three people trapped inside the vehicle. Latulippe said officers put out the small fire, adding that it appeared all three died on impact and not because of the fire.

The driver was the only occupant wearing a seat belt during the collision.

The driver was identified as a 43-year-old male from Escondido, the front passenger was identified as a 56-year-old male from Escondido, and the passenger in the left rear of the SUV is a female that is yet to be identified, CHP said.

The San Diego Medical Examiner’s Office is working to determine if impairment was a factor in the crash.