How Does an Ignition Interlock Device (IID) Work?

An ignition interlock device is easy to use and helps ensure you're safe to drive. Once installed, it works like this:

1. Blow into the device

Before starting your car, you'll blow into the device to check your Breath Alcohol Content (BrAC). If your BrAC is below the legal limit (usually 0.02), your car will start.

2. Random retests

While driving, the IID will request random breath samples to ensure you remain sober throughout the trip. Intoxalock’s one-button system makes retesting simple and safe.

3. Failed tests

If you fail a test, your car won’t start. If you fail a random retest, you’ll be prompted to pull over safely. The device will not shut off your car while it's running, but some states may require additional actions, like honking the horn or flashing lights, until the car is turned off.

How to Videos for Using an Ignition Interlock Device (IID)

We know that technology can sometimes be finicky, and oftentimes things just don’t go your way. To help you out, we’ve compiled a gallery of videos that should help relieve some stress and provide the help you need to make working your device easy. This will help to give a simple visual using one of the Intoxalock devices to show how they work. Included are videos that can help you understand how to blow into the IID to get a proper breath sample, how to start your vehicle with the IID as well as more information regarding calibrations, lockouts and retests while you are driving.

Proper Breath Sample Technique

In this video, you’ll learn how to correctly provide a breath sample into your Intoxalock Ignition Interlock Device (IID) using the blow-inhale-blow technique for smooth and accurate results.

To perform the blow-inhale-blow pattern, blow into the device for one second, inhale for one second, and then blow again until the device vibrates, typically around four seconds. Once your device displays "Passed," you're clear to start your vehicle.

Remember to avoid eating or drinking for at least 15 minutes before testing to ensure a clean sample. Follow these steps for proper use every time!

What About Random Retests While Driving?

Once your vehicle is started, an ignition interlock device will require you to continue providing breath samples throughout the duration of your trip. This ensures the vehicle is continuously operated by someone who meets the breath alcohol concentration (BrAC) requirements.

While driving, the device will ask for random breath samples to make sure you remain sober throughout your trip. Don’t worry—Intoxalock’s one-button design makes it easy to provide a sample without distraction. If you fail a retest, you’ll be prompted to pull over safely. Some states require your horn to honk or your lights to flash until you turn off the car.

You can learn more about random retests here.