RANCHO BERNARDO, Calif. -- Three people were hospitalized Sunday after a semi-trailer truck jackknifed and collided with at least two cars on Interstate 15 in Rancho Bernardo, authorities said.

The crash happened in the freeway's northbound lanes on the Rancho Bernardo Road overpass around 9:35 a.m., a dispatcher with the California Highway Patrol said.

Several people were initially trapped in the wreckage but they were able to extricate themselves before rescue crews arrived at the scene, according to the San Diego Fire-Rescue Department.

Two people were transported to Palomar Medical Center in Escondido and a third was taken to Children's Hospital, a SDFRD dispatcher said.

A hazardous materials crew was sent to the scene to clean a fuel spill.

The truck came to rest atop the center divider and blocked northbound 15's left lanes, causing a short backup in the area.