VEHICLE WAS STOPPED AT A RED LIGHT AND WAS HIT BY ANOTHER VEHICLE FROM THE REAR TRAVELING APPROX. 62-71 MPH ACCORDING TO POLICE CALCULATIONS. REAR END COLLISON RESULTED IN DRIVER SIDE FRONT SEAT/SEATBACK COLLAPSING TO THE REAR JUST AFTER IMPACT. IS THE SEAT SUPPOSE TO COLLAPSE FROM THIS TYPE OF REAR END COLLISON OR IS IT A DEFECT? SHOULD THE SEAT HAVE STAYED IN THE UPRIGHT POSITION? THE COLLAPSING OF THE SEAT MAY HAVE SAVED THE OCCUPANTS LIFE. DOES THE SAFETY BOARD TEST THESE TYPES OF REAR END ACCIDENTS AT THESE SPEEDS TO TEST THE INTEGRITY OF THE SEATS? MR