Cars are expensive. Other than a house, perhaps, few purchases we make will compare to a new car. And just like any other expensive asset, a car brings with it a secondary cost — the risk of theft.
In some laid-back parts of the world, locking the doors may be enough to ward off the threat. Everywhere else, it’s a good idea to arm yourself — and your car — with some security.
On the bright side, car thefts have been steadily decreasing in recent years; fewer than 1 million cars were stolen in the United States in 2009 [source: NICB].
That’s the lowest number in two decades, and car security has come a long way during that time period. For instance, more than 30 car models from General Motors come equipped with OnStar, a car safety device that provides everything from turn-by-turn navigation to stolen vehicle tracking and remote ignition blocking [source: OnStar]. Technological marvel that it is, OnStar’s just the tip of the iceberg — a bevy of high-tech car security systems track cars via GPS or radio, and can even kill the ignition from afar.
Source : http://auto.howstuffworks.com/under-the-hood/aftermarket-accessories-customization/10-car-security-systems.htm