VEHICLE WAS TRAVELING APPROXIMATELY 40-50MPH ON THE HIGHWAY, TRAFFIC STOPPED ABRUPTLY, COLLISION WARNING SYSTEM WITH BRAKE SUPPORT DID NOT ACTIVATE, DRIVER ATTEMPTED TO MAKE A HARD STOP, BRAKES ENGAGED AT INITIAL PUSH OF THE PEDAL THEN BECAME UNRESPONSIVE REGARDLESS OF FORCE APPLIED TO THE PEDAL, VEHICLE REAR-END ANOTHER VEHICLE, AIR-BAGS DID NOT DEPLOY, SOS POST-CRASH ALERT SYSTEM DID NOT ACTIVATE, 911 ASSIST DID NOT ACTIVATE.