VEHICLE CRASHED INTO ROCK WALL OF BUILDING AFTER UNSCHEDULED ACCELERATION AS WE WERE PARKING IT. BARELY ROLLING, FOOT ON BRAKE, VEHICLE SUDDENLY ACCELERATED ON ITS OWN, JUMPED 6" CURBING, ENGINE REVVING, WENT DOWN HILL, UNDER LOW I-BEAM OF ROOF AND CRASHED INTO ROCK WALL OF CITY HALL. IT BUCKLED WALL, SPLIT SHEET ROCK IN INTERIOR. ALTHOUGH WE SURVIVED THE INCIDENT, THE ROOF WAS RIPPED OPEN BY THE I-BEAM AND SUNROOF GLASS FILLED VEHICLE. WE NARROWLY ESCAPED WITH OUR LIVES. VEHICLE WAS NOT DRIVEABLE AFTER ACCIDENT. POLICE REPORT EXONERATED US OF ANY BLAME. FIRST INCIDENT WITH VEHICLE. *AK