A Camp Pendleton Marine died Friday night after slamming into a semi-truck north of the base, the California Highway Patrol confirmed.
CHP said at about 8:05 p.m., a 22-year-old Marine was driving his 2006 Chevy Silverado truck north on Interstate 5.
As he approached the commercial vehicle inspection area at San Onofre, he didn't seem to see a 2000 International Big Rig slowing down to enter the facility.
The Marine collided with the back of the semi-truck and became trapped underneath it, CHP officials say.
The man, who was from Kayenta, Arizona, was pronounced dead at the scene.
The 57-year-old driver of the semi-truck was not injured.
At this point, CHP officials do not know if alcohol or drugs were a factor in this crash. It is still under investigation. Officers shut down two lanes of I-5 following the crash.
As of Saturday morning, the Marine's name had not yet been released.