WHILE DRIVING INTO TOWN AT 65 MPH THE VEHICLE ACCELERATED UNCONTROLLABLY I APPLIED MY BRAKE AND IT RESUMED TO 65 FOR ABOUT 2 SECONDS THEN ACCELERATED AGAIN. I TRIED THE BRAKES AGAIN AND THEY WENT TO THE FLOOR. IN ORDER TO STOP I PUSHED THE GEAR SHIFT INTO PARK FORCIBLY. THE TRUCK WENT INTO A SPIN AND CRASHED INTO A CONCRETE BARRIER..