IN 1973, 923,600 CARS WERE STOLEN, REPRESENTING A 19-PERCENT INCREASE OVER 1968. ACROSS THE COUNTRY, 1 OUT OF EVERY 128 REGISTERED VEHICLES WAS STOLEN. MANY PRODUCTS TO PREVENT THEFT AND PROTECT AUTOMOBILES ARE BASED ON SOPHISTICATED AND ADVANCED TECHNIQUES AND USE SOME TYPE OF SOUND-MAKING DEVICE SUCH AS A SIREN, BELL, OR HORN. A DESCRIPTION OF AUTOMOTIVE SECURITY DEVICES COVERS ELECTRONIC SENSING SYSTEMS, SHAKER SWITCHES, MERCURY TILT SWITCHES, SPECIAL PIN SWITCHES, LOCKING BARS, ITEMS THAT BLAST CAR HORNS, ITEMS THAT SHUT OFF FUEL, HOOD LOCKS, SECURITY LOCKS, WHEEL LOCKS, LOCK MOUNTS TO PREVENT THE THEFT OF STEREO TAPE DECKS, IGNITION MEMORY CIRCUITS, AND AUTOMOTIVE TIMERS. THE BASIC NOVICE THIEF IS AN INDIVIDUAL WHO WILL NOT GO TO ANY GREAT LENGTH TO THWART AN ALARM SYSTEM BUT IS MAINLY LOOKING FOR AN UNLOCKED CAR WITH THE KEYS STILL IN THE IGNITION. THE PROFESSIONAL THIEF MAKES A LIVING AT STEALING CARS OR STEALING CARS FOR THEIR PARTS. SECURITY MANUFACTURERS HAVE DEVELOPED THEIR PRODUCTS TO STOP THESE TYPES OF THIEVES. PRIVATE COMPANIES AND CAR MANUFACTURERS ARE DEVELOPING EVEN MORE SOPHISTICATED DEVICES, SUCH AS THE KEYLESS ALARM SYSTEM. GOVERNMENT AGENCIES ARE ALSO INVOLVED, E.G., IN NEW YORK WHERE AN AUTOMATIC LICENSE PLATE SCANNING SYSTEM HAS BEEN PROPOSED. A MAJOR ASPECT OF ALL SECURITY PRODUCTS IS TO KEEP THE THIEF WORKING ON THE CAR AS LONG AS POSSIBLE SO THAT THE RISK OF BEING APPREHENDED IS GREATER. (DEP)