Why You Just Can’t Fool An Ignition Interlock

Often news articles about the persistent problem of drunk driving mention ignition interlocks — devices that test your blood alcohol concentration (BAC) when you blow into them. The devices are designed to prevent your car from starting if you fail the test because there’s too much alcohol in your system.

While the news articles usually mention the success that ignition interlock programs have had, if you scan down to the comments, someone is sure to have written, “Big deal. Those things are easy to bypass. They don’t prevent anyone from drinking and driving. Waste of time.”

A lot of people are under the impression that ignition interlocks are easy to defeat. Nothing could be further from the truth. Over the years the technology has been refined, and features added, so that they now do a great job keeping roads safer. Most of the ways people think they can defeat an interlock are based on a false information. Here are some methods methods by which people think they can fool an interlock:

• Have a friend blow into it. This is everyone’s first idea. Well, this will get your car started. But today’s interlocks feature a camera which records just who’s blowing into it. So when your data is sent to the authorities, expect a knock on the door.
• Start the car sober, and drink once you’re on the road. Interlocks employ a “rolling re-test” feature nowadays . That means that the device will ask you to blow into it at regular intervals after you’ve been driving for a while. If it detects alcohol, your lights will flash and your horn will honk. Not a good idea.
• Use a balloon with someone else’s breath. Apart from the general dumbness of collecting sober people’s breath in balloons and storing them in your car, this is another fail. The ignition interlock device wants to reassure itself that you’re human, so it will ask you to hum, or sometimes inhale, to prove it. Balloons just don’t do that very well.
• Remove the interlock altogether. Nope. Even if you could do it (and that takes specialized training), the data feed would register the removal, or even an attempt, and you’ll be in violation of your license terms.

There’s a reason ignition interlocks are extremely difficult, if not impossible, to fool: the stakes are so high. Often these devices are all that lie between a drunk driver and the innocent people on the road. Their job is to save lives, and statistics show they’ve been doing just that wherever they are required by law.