PARKING CAR IN HANDICAPPED SPOT - SPEED APPROXIMATELY 2 MPH - GAS ENGINE CUT IN AND THE CAR ACCELERATED AT A VERY HIGH SPEED. IT WENT OVER SPACE STOP (CONCRETE) - CROSSED THE SIDEWALK ONTO GRASS AND I HAD BOTH FEET ON THE BRAKE AND STOPPED THE CAR APPROX. 3 FEET FROM A WALL OF A BUILDING AND SHUT OFF THE ENGINE. THE HANDICAPPED SIGN SCRAPED THE WHOLE RIGHT SIDE OF MY CAR AND THERE ARE SEVERAL DENTS. THE SIGN WAS FINE. *TR