SAN DIEGO (CNS) - A school bus full of students caught fire on Interstate 15 in City Heights Monday, but no one was injured.

Smoke was seen coming from around the rear tire of the bus shortly after 8:30 a.m., prompting its driver to pull over on the side of the freeway south of University Avenue, according to the California Highway Patrol.

Firefighters were sent to the scene, but the blaze was out by the time they arrived, a San Diego Fire-Rescue Department dispatcher said.

The vehicle's occupants, about 40 people, were able to exit and were waiting on the roadside for another bus, the CHP said.

The disabled bus was blocking one northbound lane, according to the CHP.