WHILE DRIVING DOWN A HILL CRUISE CONTROL LIGHT ILLUMINATED. WHEN THIS OCCURRED VEHICLE ACCELERATED TO 70 MPH. IN AN ATTEMPT TO DECREASE SPEED CONSUMER DEPRESSED THE BRAKE PEDAL SEVERAL TIMES IN DRIVE THEN IN NEUTRAL , BUT THE ATTEMPT FAILED. AS A RESULT VEHICLE WENT OVER A GUARD RAIL, AND ROLLED DOWN A MOUNTAIN. CONSUMER SUSTAINED A CONCUSSION AND INJURIES TO SEVERAL BODY PARTS. VEHICLE WAS TOTALED. *AK