WHILE TURNING INTO AN ANGLED PARKING SPOT IN A PARKING LOT, THE CAR ACCELERATED UNEXPECTEDLY. BEFORE I COULD ENGAGE THE BRAKE, THE CAR WENT OVER THE CONCRETE BERM SEPARATING ROWS OF PARKING SPACES AND HIT TWO PARKED CARS. ALL THREE VEHICLES WERE DAMAGED (THE VEHICLE I WAS DRIVING, AND THE TWO PARKED VEHICLES). WEATHER WAS NOT A FACTOR. THE PARKING LOT WAS DRY AND FREE OF SNOW AND ICE. THE TEMPERATURE WAS ~40F. THE CAR WAS NEW (3 MONTHS OLD) WITH ~550 MILES ON THE ODOMETER. THE SAME BEHAVIOR (UNEXPECTED ACCELERATION) HAPPENED ~1 MONTH EARLIER UNDER SIMILAR CONDITIONS, I.E., DRY, SNOW/ICE FREE WHILE TURNING INTO AN ANGLED PARKING PLACE. FORTUNATELY, THAT TIME I WAS ABLE TO ENGAGE THE BRAKE BEFORE DAMAGE WAS DONE. IN BOTH CASES, THE CAUSE OF THE BEHAVIOR IS NOT KNOWN.