REAR END COLLISION WHILE STOPPED AT LIGHT. UNCERTAIN OF STRIKING VEHICLE SPEED. MAZDA REAR CRUMPLED SUFFICIENT TO DISTORT REAR DOOR FRAMES. BOTH FRONT SEAT MECHANISMS RELEASED AND OCCUPANTS WERE LAYED OUT FLAT. ONLY TWO OCCUPANTS IN CAR, APPROXIMATELY 225 LBS. EACH. MINOR NECK INJURIES (MUSCLE PULL?) RESULTED.