PULLED CAR INTO LINED PARKING SPACE, PLACED CAR IN PARK, TURNED CAR OFF (KEYLESS IGNITION "SMART KEY" ON DASH TURNED TO LEFT/OFF POSITION, ABOUT TO GET OUT OF CAR, JUST STARTED TO TAKE SEAT BELT OFF WHEN CAR STARTED UP, WENT UNCONTROLLABLY FORWARD OVER CEMENT PARKING BARRIER AND CEMENT WALKWAY AND HIT PARKED VEHICLE ON OTHER SIDE OF LOT, ALL THE WHILE SHIFTER IN PARK POSITION AND FOOT ON BRAKE, TRIED TO KEEP CAR STRAIGHT, BUT WOULD NOT RESPOND AND VEERED TO THE RIGHT. AFTER THIS FIRST IMPACT SHIFTER SLIPPED FROM PARK TO REVERSE ON OWN AND CAR WENT BACKWARDS AGAIN OVER CEMENT BARRIER AND WALKWAY AND HIT CAR BEHIND AND FINALLY CAME TO REST. IN GOING BACKWARDS BRAKES DID NOT AGAIN RESPOND. THIS WAS EXPERIENCED AND WITNESSED BY TWO OTHER PASSENGERS INSIDE THE CAR, TOW TRUCK PERSONNEL ALSO NOTED THAT AFTERWARDS, WHEN PLACED IN NEUTRAL TO PUT ON FLATBED, CAR SHIFTER HAD TENDENCY TO GO TO REVERSE OR FORWARD GEAR. POLICE REPORT STATED THAT "IT APPEARS THAT A VEHICLE MALFUNCTION COULD HAVE BEEN THE CAUSE OF THE CRASH". THIS VEHICLE IS A BRAND NEW 2006 LEXUS LS430, PURCHASED 5/30/06 WITH ONLY 4800 MILES ON IT! DRIVER AND ONE PASSENGER HAVE SOFT TISSUE MUSCULOSKELETAL INJURY/PAIN AND DRIVER HAS ANXIETY/ PANIC ATTACKS WHENEVER ATTEMPTING TO DRIVE, AND IS RECEIVING PROFESSIONAL MEDICAL ASSISTANCE AND MEDICATIONS TO TREAT THIS. NOTHING THUS FAR HAS BEEN DONE BY LEXUS TO CORRECT OR PREVENT THIS FAILURE FROM POTENTIALLY RECURRING AGAIN, THE CAR IS PRESENTLY HAVING THE PHYSICAL DAMAGE REP