VEHICLE WAS TRAVELING 45 MPH ON FIRESTONE, AFFINITY TIRES WITH LESS THEN 20,000 MILES ON THEM. WHILE TRAVELING ON DRY, GOOD PAVEMENT THE RIGHT REAR TIRE EXPERIENCED A COMPLETE BLOWOUT CAUSING THE VEHICLE TO TURN VIOLENTLY TO THE LEFT AND COME TO A COMPLETE STOP IN A BAR DITCH. THE TIRE WAS INTACT, BUT HAD CRAWLED OFF THE RIM. TIRE PRESSURE WAS CHECKED TWO DAYS PRIOR AND WAS WELL WITHIN PROPER LIMITS OF THE REQUIRED PSI. THE VEHICLE WAS TOTALED AS A RESULT OF THE BLOWOUT AND CRASH..