5 SECONDS AFTER STARTING THE VEHICLE IT SUDDENLY WENT INTO UNINTENDED ACCELERATION FROM 5MPH TO ABOUT 40 MPH. I IMMEDIATELY APPLIED THE BRAKES BUT THE CAR WOULD NOT SLOW DOWN OR STOP. I THEN SHIFTED INTO NEUTRAL WHICH DID NOTHING, THEN SHIFTED INTO PARK, WHICH DID NOTHING. STILL APPLYING THE BRAKES I TRIED NUMEROUS TIMES TO SHUT (PUSH BOTTON) IGNITION OFF BUT THAT WAS UNRESPONSIVE. I HIT A STREET SIGN WHICH SLOWED ME DOWN AND THE CAR FINALLY CAME TO A STOP BUT THE ENGINE WAS STILL REVING LOUDLY FOR ANOTHER SOLID MINUTE. I AGAIN WAS PUSHING THE IGNITION BUTTON AND THE CAR THEN SUDDENLY TURNED OFF.