Look at any typical police blotter and generally the most frequent crime listed will be related to automobiles. Whether it's grand theft auto or simple burglary of items within the car or even carjacking, autos and crime seem to go together is just about every locale in the world. This is where a good car alarm can come in handy. While an alarm won't guarantee theft won't happen, it can lessen the chances. Anything to deter is a good idea.

Shopping for car alarms can be a little tough though. There are a number of different devices on the market that offer one form of protection or another. The prices vary greatly. The high-end devices can even track a stolen car to its current location and lower end options simply lock steering wheels. Some may be more effective than others in scaring off the professional thieves, but any type of alarm or lockout device is better than none.

In the car stealing game, law enforcement will say that anything that adds even seconds onto the time it takes a thief to steal a car will help turn them to the next car in the lot. That's right, just seconds can count. The idea is that if another mark is easier to hit, the thief will move on to it instead. While this isn't always so, any type of deterrant is really better than none.

As you shop for a car alarm, you'll find there are a ton of different options available. Here are the two major types of systems:

* Passive alarms: These automatically turn on when the ignition is off and the doors are closed. If the car is opened incorrectly, i.e., without the key or the ignition is forced, an alarm will sound.

* Active alarms: These must be manually turned on by the user. The problem here is the user may forget.

Both types of alarms can come with a number of different features, depending on the alarm purchased. They can include such things as door sensors, motion detectors, air horns and more. The idea behind them is to make enough noise to scare off a would-be thief.

Some alarms and anti-theft devices even come with a tracking mechanism. Although more expensive than simple air horns, these devices can and do prevent a stolen car from making it to a chop shop. Think of it as a personal homing device for a car and you get the idea.

Alarms can be very simplistic or extremely complicated. No matter the type that's purchased, remember they must be turned on to work. The idea is to deter - to make your car look less attractive to thieves than others in the lot. It sounds harsh, but it's a dog-eat-dog kind of world out there. Just look at news headlines or police blotters and you'll see.

Even a simple steering wheel lock is better than nothing, but to truly present a problem for thieves, more complex systems with horns, tracking devices and battery backups should be considered.

Buying a car alarm should be almost as important as buying the car in some locations. Considering the alarm protects a big investment, it only makes sense. Plus, alarms can provide some good discounts on insurance, too.