The airplane was substantially damaged and the Student pilot sustained minor injuries at about 2310 Pacific time when the airplane lost engine power and collided with an automobile during a forced landing on a freeway. The CFI aboard sustained serious injuries. Visual conditions prevailed for the cross-country flight. The CFI subsequently reported that, after switching from the auxiliary fuel tank to the left main fuel tank, the engine quit running. The Student pilot/owner began pumping the manual wobble fuel pump and turned on the electric fuel pump. The two tried each fuel tank, and, each time, the engine quit running when they stopped using the wobble pump. At 500 feet agl, they set up for a forced landing on the freeway. In the flare just prior to touchdown, the left wing struck an automobile and the airplane cartwheeled before coming to rest upside down.