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September 29, 2020

How Ignition Interlock Device Works

An ignition interlock device (IID) is known by many other names: interlock device, interlock system, and car breathalyzer, to name a few. However, while the terms vary, the device’s purpose and function remain the same—prevent drunk drivers from driving a vehicle while intoxicated.


The Lowdown on Ignition Interlock Devices

The first ignition interlock device was first introduced in the 70s. Nowadays, all 50 states have enacted a form of ignition interlock law that requires DUI offenders to install an interlock device on their vehicle to retain their driving privileges.

Statistics show that at least 30 people die in drunk-driving accidents in the United States—this translates to one person every 50 minutes. Drunk driving also claims more than 10,000 lives each year. Ignition interlock devices and the laws that govern them are designed to minimize these deaths and other injuries.

An interlock device is equipment that’s installed in the vehicle of a person convicted of DUI. It works like a breathalyzer, requiring the driver to pass the test to start the car. The device is slightly bigger than a cell phone and will require the driver to blow into the device.

How an Ignition Interlock Device Works

An ignition interlock device is hard-wired to the car’s ignition system. It requires the driver to provide a breath sample first before the vehicle can start. It is also designed to interrupt the car’s ignition system and won’t allow it to begin until a passing test is provided.

Typically, the device is located on the car’s dashboard. After the driver blows into the handheld device, it measures the blood alcohol content (BAC). If it is over the limit allowed by the state, the vehicle won’t start.

To make things easy for you, our interlock device can self-diagnose problems and you can gauge if there are any issues through the service light. You can also give us a call anytime to determine if your IID needs servicing.

Generally, interlock devices are set up to provide “rolling retests”. These tests are designed to ensure the driver did not let anyone else blow into the device to start the vehicle. The rolling retests are carried out at random intervals once the driving has begun.

The rolling retests are also done to warrant the vehicle’s driver won’t consume alcohol while on the road. Since the device records the BAC each time, the report can be downloaded and provided to the court when required.

Other information the ignition interlock device records include:

  • Date, time, and results of the start-up tests
  • Date, time, and results of the rolling retests
  • Location (if the device is GPS equipped)
  • Driver’s picture (if the device is camera-equipped)
  • Times driver skips a rolling retest
  • Attempted removal or tampering of the device

What Happens if You Fail a Breath Test


Every state has different requirements. However, for those who fail the test several times, the state may extend the device’s time in the vehicle. Another possibility is you can get kicked out of the program and your full license suspension will be reinstated.

If you are looking to get your full driving privileges back as soon as possible, you must comply with all the program regulations. If you have been drinking, you can either sleepover at a friend’s house or have a friend take you home, whatever is necessary to avoid additional penalties.

Interlock Device Exemption

When required, there are hardly any situations where an exemption can be made. The primary scenario where an exemption may be possible is if the offender does not own a vehicle and can prove to the court that they won’t be operating any vehicle.

Also, since they have a suspended license, they won’t be able to legally drive any car or motorized vehicle until the suspension is over.

Where to Get an IID Installed

When the court orders the device’s installation, the setup is always more of a lease agreement. An installer authorized by the state or trained and authorized technicians can install the system and guide how it should be used.

At Interlock Install, we provide the most efficient interlock installation in Phoenix, Arizona. As your chosen installation and service facility, we will do everything to assist you and ensure you get nothing but the highest level of quality and customer service.

Unlike most, we solder all our wiring connections when installing the interlock device into your vehicle. This is done to ensure there are no intermittent connections or voltage drops. For utmost ease and convenience, we have a mobile service available (for a small fee).

The small fee will cover vehicle and employee time. For many, it’s a small price to pay for the convenience of having your service appointment, installation, or IID removal done at a location that’s convenient for you.

Installation Cost

Typically, IIDs can cost between $60 to $90 per month. Some states offer financial assistance to cover the cost for those who qualify.

The cost of the individual monthly lease payments will depend on a few factors, such as:

  • Length of time you’ll need the device
  • Model of the device (camera, GPS, real-time reporting)
  • Frequency of compliance reporting that’s required by the home state
  • Other fees or taxes (in accordance with the state laws)

When it comes to installation costs, expect that you will pay for the installation fee, monthly service appointments, and the removal fee.

Need an IID Installed? We Can Help!

If you want an IID installed, get in touch with us. We will be assisting you every step of the way. After all, here at Interlock Install, our primary goal is to get you back on the road interlock free!

Coming Soon

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Who Referred You? Streetfighter Motorsports Coupon must be present at time of install. Offer valid for new installs only. Coupon Code: AZ125