PEOO, 020; CONSUMER WAS TRAVELING ABOUT 70MPH ON HIGHWAY AND WAS PASSING ANOTHER VEHICLE, WHEN IT STARTED VIBRATING. TIRE TREAD CAME COMPLETLY OFF, AND ONE SOLID PIECE, AND IT TORE THE RUNNING BOARD OFF/BROKE THE RUNNING BOARD IN HALF. THEN, IT SLAPPED UP AND DENTED THE TAILGATE/ SIDE AND REAR. TIRES WERE FIRESTONES#ATX, SIZE P235/75R 15 . THERE WERE NO INJURIES REPORTED AT THIS TIME. *AK