SPEED CONTROL: DRIVING DOWN HIGHWAY, ATTEMPTING TO EXIT ON A OFF RAMP, TRIED TO TURN THE CRUISE CONTROL OFF, CRUISE CONTROL WOULD NOT GO OFF, COULD NOT BRAKE. EXITED OFF RAMP AT APPROXIMATELY 65MPH, WENT THROUGH STOP SIGN, ENTERED ANOTHER HIGHWAY, HIT CURB AND MEDIAN, AND VEHICLE STOPPED. *AK *NLM