A driver was killed and two Caltrans workers were injured when a car crashed on the 405 Freeway in Huntington Beach Thursday night.

The crash occurred on the southbound side of the freeway near Beach Boulevard, California Highway Patrol Sgt. Michael Stoney said.

Caltrans workers were in the process of setting up a planned closure when the car, described as a Dodge Dart, crashed into the sign truck and trailer.

Two Caltrans workers struck by the vehicle were hospitalized with injuries that were not believed to be life threatening, Stoney said.

The unidentified driver of the Dodge was pronounced dead at the scene.

Traffic was being diverted off the southbound 405 Freeway at Beach Boulevard as crews responded to the collision.

The cause of the crash is under investigation.