A Sacramento man died early Saturday morning following a single-car accident on Interstate 5 that left the vehicle fully engulfed in flames, police officials said.

The accident happened just after 4 a.m. Saturday morning on southbound I-5 near Airport Boulevard when the 21-year-old woman driving the car veered off the road and crashed. California Highway Patrol officials said there weren't any witnesses to the accident, but several passersby pulled over to help.

"Numerous people stopped to help," CHP officials told ABC10 News, "including one driver of a big rig, who ended up pulling the driver of this car away from the scene as it was becoming fully engulfed."

The 25-year-old passenger of the car was pronounced dead, and the driver suffered a broken leg.

CHP officials said they don't know what led to the crash, but "don't suspect drugs or alcohol played a role."