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If you’ve recently been ordered to use an Ignition Interlock Device (IID) as part of your DUI or DWI arrest, you’re probably wondering how to get started. First of all, it’s important to recognize you’re not alone in this: most states (and the District of Columbia) have an ignition interlock law in place.

The laws appear to be having an impact on keeping the roads safe. According to MADD, IIDs prevented 354,372 drunk driving attempts in 2017. By using an IID, you’re not only following the law — you’re helping to prevent future accidents. Here’s what you need to know about how to use an IID.

What is an IID?

Let’s start off with the basics. IIDs were designed to prevent people from drinking and driving. It requires you to breathe into a mouthpiece before starting your car. The device then measures how much alcohol is concentrated in your breath. If you have a Breath Alcohol Concentration (BrAC) higher than the legal limit in your state, your car will not start. If you have a BrAC under the limit, the device will allow your car to start. It’s as simple as that.

If you’ve been ordered to install an IID in your vehicle, find a provider and get started on the process. Do not tamper with or attempt to remove the IID; depending on your state, you could get a fine, license suspension, or even jail time.

IID How To: Three Easy Steps

Though it can sound intimidating at first, we’re here to walk you through the simple process of obtaining and using your IID:

1. Find your IID Provider & Get it Installed

Once you know you are required to have an IID installed on your vehicle, your next step is to find an IID provider, who is authorized to install in your state. We offer free installation in select locations. Contact us to see if you are eligible.

When it’s time to go to your installation appointment, make sure that you bring documents to prove your identity, including your driver’s license, registration, proof of residence, and court order. Before you have the device installed, it’s important that your vehicle is in good working condition.

2. Breathe Into the Mouthpiece

Once your IID is installed, you’ll have to use the device each time you turn your car on. You may also be required to perform rolling retests. You will have a few minutes to pull over to provide the retest. That is why it’s so important to choose an IID that is ready as soon as your vehicle is switched on (some take up to three minutes). When you get into the car, do the following:

  • Press start or turn your key
  • Blow into the mouthpiece, then quickly suck back in
  • If the test is passed, start your engine and go

This simple step will be repeated each time you turn you switch your car on. Keep in mind that there may also be a visual component to your IID. By looking into the camera, the device’s facial recognition software confirms your identity. This safeguard is put in place to ensure that the person who blows into the mouthpiece is the same person who will be behind the wheel.

3. Drive — You’re Good to Go

Once your BrAC is measured, and the results are less than the legal limit, the IID allows you to start your vehicle so that you can get on the road. If your BrAC is at or above the legal limit, your car will not start. Our ignition interlock devices can easily differentiate between breath alcohol and mouth alcohol (such as mouthwash), so you don’t have to worry about unnecessary lockouts!

RoadGuard Interlock Is Here For You

At RoadGuard Interlock, it’s our goal to provide the highest quality IIDs. Our devices are fast and can get you on the road within seconds. We understand the need for discretion; RoadGuard Interlock devices are designed to be sleek, resembling the shape of a cell phone. Most of all, we trust our customers with respect. Please don’t hesitate to contact us if you have any additional questions.


*Links to any third-party websites herein are provided for your reference and convenience only. RoadGuard Interlock did not create nor develop and does not own any such third-party websites. RoadGuard Interlock does not endorse nor support the content of, nor any opinions stated in any such third-party website links. RoadGuard Interlock is not responsible for the content of any third-party website or its accuracy or reliability. Nothing contained in this article or in any such third-party website shall be considered legal advice or be deemed to constitute legal advice. For any legal advice concerning a DUI arrest, charge, conviction, or consequences thereof, you should contact an attorney of your choice.