SINGLE OCCUPANT IN VEHICLE (DRIVER) VEHICLE WAS FORCED OFF THE ROAD AND ENTERED A DITCH ABOUT THREE-FOUR FEET DEEP. PASSENGER'S AIR BAG, FRONT, FIRED. THE AUDI A8 CLEARLY STATES IN THE SALES LITERATURE THAT THE PASSENGER'S AIRBAG IS INTERLOCKED OUT WHEN NO PASSENGER IN THE VEHICLE. THE DRIVER WAS THE ONLY OCCUPANT AND THERE WERE NO PARCELS, SHOPPING BAGS, AND ETC. ON THE PASSENGER'S SEAT. AUDI & THE DEALERSHIP HAVE BEEN HIGHLY UNPLEASANT TO DEAL WITH CONCERNING THIS "PERFECTLY NORMAL OPERATION OF THE PASSENGER'S AIRBAG."