Car theft has many variations. The most common occurrence of the crime is theft of the vehicle without using a key while it’s left unattended. Usually, the criminal hotwires the ignition or otherwise tampers with the car’s systems in order to drive it away. If the owner was smart and locked the doors, the thief will break a window or use a tool to jimmy the door lock or pry the door open. Car alarm systems are designed to prevent this type of crime by tripping a switch when someone opens the doors or trunk while the vehicle’s owner has armed the system. The switch triggers attention-grabbing devices like horns, sirens, and flashing lights to alert bystanders and law enforcement. High-end vehicle security systems also have sensors that can detect the sound of breaking window glass, and devices that sense when someone is standing within touching distance of the vehicle. Auto alarms that feature ignition and starter system lockout devices are very good at frustrating hotwiring attempts.

A second type of theft without keys is towing, where the bad guys drive up in a tow truck or flatbed trailer and steal the vehicle without starting it. More and more alarms are being offered with sensors that detect when a vehicle is tilted slightly, in preparation to tow it away or drive it up on a flatbed truck.

Theft with access to keys happens most often when the thief knows the vehicle’s owner and can easily get the key to the automobile. Also known as “taken without consent” by law enforcement personnel, this is a common crime by juvenile children of the owner, family members with alcohol or drug problems, or the vehicle owner’s employee. If you think this might happen to you, a key with a special code embedded in it will prevent the key being used by anyone but you.

A third type of car is opportunistic theft, where the vehicle was stolen while left with the keys in plain view—often with the engine running. The best auto security device to prevent this type of theft is your brain: don’t leave your car with the keys available, even for a few seconds. Hiding a spare key on the vehicle frame falls into the same category of making life easy for thieves.

A more serious type of car theft is carjacking, where the thief uses force or threats to get control of the vehicle away from its owner. Courts treat this crime very seriously, since assault is always part of the process. Usually the carjacker gets the passengers out of the vehicle and drives it away, but occasionally, hostages are taken. A few alarms come with carjacking protection devices that disable all of the car’s systems and set off a siren when the owner flips a switch, but these have the danger of doing more harm than good.

A thief’s tools of the trade are simple but effective. Slide hammers can make short work of a door lock. The “Slim Jim” device that tow truck operators use to open vehicles that the owner has locked themselves out of consist of a flat hook to insert between the car’s frame and window glass. Some simple electrical supplies are used for hotwiring, such as spare wiring and a DC meter to find where the battery current connects to the ignition. Recently, theft has gone high tech as thieves attempt to use laptop computers to pick the ignition code of RFID key theft prevention devices and come back later to steal the vehicle after the owner has gone. This type of theft is rare, however.

Why do people steal cars? Some thieves just want short term transportation to drive for a few days and then abandon. Many times, the thief will use your car to commit other crimes, so the vehicle’s license plate and description can’t be traced to him. Other thieves need transportation out of state and know that once they cross the state line, the odds of getting caught go down—especially if they switch license plates once or twice along the way.

Some thieves steal cars to resell, either whole, with the VIN altered, or to be chopped down and sold for parts. If your car is stolen by a chop ring, your chances of getting it back are poor. Newer auto security approaches include VIN etching and microdot identification on parts and even the paint job to put a unique fingerprint on parts that might be sold after theft.

Finally, some car thieves steal cars so they can go joyriding. This most commonly occurs in instances of opportunistic theft, but a good car alarm system can go a long way toward preventing this type of crime.

Vehicles most likely to be stolen include the Cadillac Escalade, Jeep Cherokee, Honda Accord, and Toyota Camry. The late model Dodge Charger, an expensive luxury sports car, has become a recent favorite of car thieves.

Vehicle security systems come in different types. If you really want to keep your car from getting stolen, you should take a multi-faceted approach to auto security and try to use as many of these approaches as you can afford.

Barrier devices put a physical object between the thief and your car to make theft more challenging. For example, you can buy a basic lockout device like “The Club” to clamp on your steering wheel, or a lockout lever for your brake pedal. Another type of physical barrier is the immobilizer switch that disables the starting system unless you insert a coded key device in the ignition. Kill switches work on a similar principle, but are designed to be flipped by the vehicle owner, rather than activated by the ignition key. To really be effective, the switches are hidden in obscure locations around the vehicle and have to be flipped in a certain order known only to the owner.

Most car security systems work through deterrence. Although the thief can physically steal your car, these systems make it more likely that he’ll get caught. Car alarms respond to a breaking and entering of your car by making noise and flashing lights on and off. Signage on your windows and flashing LED lights also let car thieves know that your car isn’t a safe target for theft.

If your car is stolen, there are auto security devices that help you and the police track it down. VIN etching and microdot ID tags can trace parts that were taken off the car in a chop shop. More car manufacturers are offering these as options. GPS tracking devices also are available as factor options. Other tracking devices include the LoJack, which emits a radio signal from the car, enabling law enforcement to track its whereabouts and return it to its rightful owner.