THE VEHICLE WAS STOPPED IN A DRIVEWAY, I SHIFTED THE TRANSMISSION INTO REVERSE AND THE THROTTLE ACCELERATED FULL ON. I TRIED TO BRAKE THE VEHICLE AND TURN IT OUT OF THE STREET BUT I COULD NOT OVERRIDE THE ACCELERATION AND BACKED INTO A BOLDER RETAINING WALL. TOYOTA INSPECTED THE VEHICLE AND SAID IT SHOWED ACCELERATION AND BRAKING BUT DENIED RESPONSIBILITY.