Are car alarms actually helpful?

When you hear the 125 decibel jet-engine level bleating of a car alarm, do you race to the phone to call the authorities, or do you instead fantasize about dropping a couch on the offending car, like that old Snickers commercial? Statistically speaking, we’d bet you’re more likely to (want to) go for the couch—one survey found that fewer than 1% of people reported that they would call the police if they heard an alarm, most likely because car alarms are infamous for going off at the slightest provocation. In related news that isn’t so great for car alarms, another study found that over 99% of the time, they’re false alarms—rumbling trucks, a too-close door opening, system malfunction, you name it.

But false alarms and lack of bystander action doesn’t necessarily mean car alarms are worthless—they’re theft deterrents, and if they do in fact deter would-be criminals, they’ve done their job. Those 99% of activated alarms can be false if thieves don’t bother with alarmed cars in the first place.

So, The Zebra wondered, what’s the real story?

How effective are car alarms

If you ask the car salesman trying to sweet talk you into a car alarm for your new (or new-to-you) car, they’re the only thing between your car and the friendly neighborhood chop-shop. But do they work, really?

ABC News interviewed former car thief Steve Fuller. When asked about the effectiveness of car alarms Fuller said, “Good alarms with motion sensors, nosy neighbors, and security cameras also deter car thieves, who will simply go to other areas where they can avoid those certain things.” However, on the other hand, according to Carlock, 80 percent of car thieves can disable a car alarm in under a minute. So, while a blaring alarm might deter joyriders and inexperienced thieves, a true pro won’t likely be stopped. It should be noted, also, that up-to-date comprehensive studies examining the effectiveness of car alarms are sadly lacking.

How to protect your car

While no current studies definitively prove that car alarms aren’t worth the trouble, the data does suggest that vehicle recovery systems—such as OnStar and LoJack—and immobilizers (computer chips in your key that the car must sense in order to start) are more effective than audible alarms.

Some additional tips for protecting your car, from Esurance:

• Always lock up
• Grab your keys: Leaving your keys in the ignition is like sticking a “Steal Me!” sign on your car. Same for leaving your car idling.
• Follow the light: Parking in well-lit areas is safer for you and your car. Since light makes it easier for car thieves to be spotted and identified, odds are they’ll be less likely to mess with a car that’s parked under bright lights.
• Shut your windows and sunroof: Leaving them open, even just a crack, encourages break-ins.
• Avoid leaving valuables in your car: Shopping bags, suitcases, laptop accessories, GPS devices, and smartphones entice thieves. Keep all packages and other valuables in the trunk if you have to leave them in your car.
• Use a smart key: When car shopping, look for models with smart keys, which have unique computer chips that can’t be duplicated or altered. A driver needs that key, and that key only, to start the ignition.

If your car is stolen, comprehensive coverage could cover the cost, so you might consider adding it to your plan (if you haven’t already).

The bottom line

Results vary from company to company, and of course from insured car to insured car, but it seems most auto insurance carriers believe in the effectiveness of car alarms—at least enough to offer (sometimes small) discounts for drivers who have them. Some carriers lump car alarm discounts in with all anti-theft devices (such as vehicle recovery systems), but depending on where you live and what type of car you have, you could see savings from 5 to 25 percent with anti-theft devices. Car alarms can cost anywhere from $100 to $1000 (or more), so you’ll want to weigh potential insurance savings against the cost of the system.

Did a car alarm prevent theft for you? Have you found them useful? We’d love to hear from you — tell us in the comments.