VEHICLE WAS INVOLVED IN A FATALITY CRASH DURING WHICH THE DRIVER HEADREST INCLUDING ANCHORS CAME OUT OF THE SEAT BACK AND WAS OBSERVED IN THE PASSENGER FLOORBOARD. THE VEHICLE WAS STATIONARY (DISABLED - OUT OF GAS) PARTIALLY IN A MOVING LANE OF TRAFFIC ON A HIGHWAY AT THE TIME OF THE CRASH AND STRUCK BY A MOVING VEHICLE.