PARKED TOYOTA AVALON WAS STARTED, SHIFTED INTO DRIVE AND UNCONTROLLABLE ACCELERATION OCCURRED. BRAKES INEFFECTIVE SO HIT PARKED CAR IN FRONT EXTREMELY HARD. TRIED TO SHIFT TO NEUTRAL BUT IT SLIPPED INTO REVERSE AND HIT CAR PARKED BEHIND. FINALLY GOT INTO NEUTRAL AND TURNED OFF ENGINE. VERY, VERY SCARY. NO INJURIES, NO POLICE REPORT, NOTIFIED INSURANCE TO COVER DAMAGES TO CARS. WILL HAVE TOWED TO TOYOTA FOR INSPECTION. IF NOTHING FOUND, I WILL NOT DRIVE THIS CAR AGAIN. WITNESS SAID CAR "JUMPED UP AND ACCELERATED UNCONTROLLABLE". *JS