ANAHEIM (CBSLA.com) — A motorist was hospitalized Wednesday after being struck by a big rig on the 91 Freeway in Anaheim.

According to California Highway Patrol officers, the crash occurred just after 4 a.m. in the westbound lanes of the freeway near the 57 Freeway interchange.

A preliminary investigation revealed the driver of a Toyota Camry, which broke down on the freeway, was struck by the big rig.

Paramedics transported the driver to a hospital in serious condition.

CBS2's Mark Dunn reported CHP officers and Caltrans are treating the incident as a fatal crash.

Westbound lanes of the freeway remain closed until around 6:30 a.m., officials said.

The cause of the crash remains under investigation.