MY WIFE RETURNED FROM BUYING PRESENTS AND STOPPED THE VEHICLE IN THE DRIVEWAY. SHE ENGAGED THE HANDBRAKE AND WAITED ONE MINUTE BEFORE TURNING OFF THE ENGINE TO LET THE TURBOS COOL DOWN. SHE THEN PROCEEDED TO RETRIEVE PACKAGES FROM THE TRUNK AND ENTERED THE RESIDENCE. AFTER ONE HOUR AND FOURTY FIVE MINUTES, AN OFFICER CONTACTED US AND ASKED IF WE KNEW WHERE WAS THE VEHICLE. WE STATED THAT IT WAS IN THE DRIVEWAY. HE TOLD US TO PLEASE FOLLOW HIM. WE WENT OUTSIDE AND SAW THAT THE VEHICLE HAD BACKED OUT OF THE DRIVEWAY AND DAMAGED THE RETAINING WALL OF OUR VEHICLE. UPON INSPECTION, THE OFFICER NOTED THAT THE HAND BRAKE WAS STILL ENGAGED AND THERE WAS NO SIGNS OF CRIMINAL INTENT. IN ADDITION, THE ALARM WAS NOT SET OFF UPON IMPACT WITH THE RETAINING WALL. THE VEHICLE MUST HAVE REACHED A SUBSTANTIAL SPEED BECAUSE IT JUMPED THE CURB AND DAMAGED THE WALL, CREATING A HOLE ABOUT 3 FEET TALL BY 5 FEET WIDE. THE VEHICLE'S TRUNK WAS IMBEDDED THROUGH THE WALL. I ENTERED THE VEHICLE AND HAD TO DISENGAGE THE HAND BRAKE BEFORE THE VEHICLE COULD BE EXTRACTED FROM THE RETAINING WALL. DAMAGE OCCURRED TO THE REAR BUMPER, LEFT AND RIGHT QUARTER PANEL, REAR LIGHT ASSEMBY, TRUNK LID, AND TRUNK INTERIOR. POSSIBLE DAMAGE TO WHEELS AS WHEEL AS NONVISIBLE COMPONENTS OF VEHICLE.