A motorcyclist was flung under a semi-truck after crashing into a car, prompting a major closure on the southbound Interstate 5 in Oceanside Saturday.
The incident started when the motorcyclist -- a man in his early 30s -- and a Toyota Corolla collided around 8 p.m. just south of Oceanside Boulevard, according to the California Highway Patrol.
The rider and his bike were then tossed under a semi-truck.
"He was trapped under the rear axle of the big rig," said CHP Officer Chris Parent. "He was dragged about a 150 feet and under the big rig the entire time."
The motorcyclist was taken to Scripps La Jolla Hospital with major injuries.
The crash blocked all southbound lanes of I-5, forcing the CHP to issue a Sig Alert.
Officers were able to open one lane of traffic about 20 minutes later. By 10 p.m., two more lanes were opened.
Investigators are still trying to determine whether the motorcyclist or the driver of the Toyota was at fault.