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Nowadays, every US state has some sort of legislation about ignition interlock devices for drivers with alcohol-related offenses. And if you have an alcohol-related offense in a particular state, you may be required by law to obtain a breath alcohol ignition interlock device (BAIID) that is installed in your car and connected to your ignition. But there are a lot of names for these devices. So what is the difference between a car breathalyzer and an ignition interlock? Read on to find out.

Car breathalyzer versus ignition interlock device

You’ve probably run across the term “breathalyzer” in everyday speech. It actually comes from the Breathalyzer(R), the brand name of Robert F. Borkenstein’s invention which came out in 1954.

Over time the word became known as the generic term for any device designed to test alcohol levels from a breath sample. But nowadays, legal documents and manufacturing companies frequently use a variation of the term “ignition interlock.”

Such phrases like “car breathalyzer,” “in-car breathalyzer,” and “ignition interlock” all describe the same device.

Here is a list of the most common names for a breathalyzer installed in a vehicle:

  • Alcohol ignition interlock
  • Breath alcohol ignition interlock device (BAIID or IID)
  • Car breathalyzer
  • In-car breathalyzer
  • Ignition interlock
  • Ignition interlock device
  • Interlock
  • Interlock device

How ignition interlock devices work

1. The first test

You breathe into the device to submit a sample before you start your vehicle. It then measures the amount of alcohol it detects in your system. (Sometimes it’s the same level as the DUI limit for that state; in other instances, it is well below that level.) If your alcohol concentration exceeds the legal level, the device will prevent your vehicle from starting.

2. The rolling retest

Once the car is in motion, you will be required to submit breath samples again, in some cases several times. Expect the rolling retest to take place within the first five or ten minutes of your drive. If you don’t feel comfortable performing the rolling retest while driving, remember that you’re typically allowed around seven minutes to perform the test. That way, you’ll have time to pull over to the side of the road and provide a breath sample safely.

3. Safeguards

In many states, ignition interlock devices are required to be equipped with a camera. The camera is meant to ensure a sober driver is behind the wheel and to detect a change in driver. If a change in driver is detected, you may be required an additional breath sample to confirm sobriety.

Some of the latest ignition interlock devices are also able to detect attempts to manipulate or circumvent the device. Any violations such as failing a test, missing a test, or attempting to tamper with the device, will be sent to the monitoring authority. Also, if someone else drives the car and fails the test, you will be held accountable. Ultimately, you are responsible for other drivers who take the test.

Shopping for an ignition interlock device in your state

If you are required to have an ignition interlock installed, there are essential features you need to look for in the device and its manufacturer:

  • Cost: Fees will vary from state to state, but BAIID manufacturers like RoadGuard Interlock try to keep your overall costs down. Here is some information about the fees you can expect if you are required to have a BAIID installed.
  • Speed and Ease: Look for devices that call for the most straightforward procedures that can be completed without delays.
  • Respect and clarity: The company representatives for the device you buy should always treat you with respect and professionalism. And all instructions, forms, and policies should be clear and easy to follow.
  • Longevity: It’s important to work with an experienced company whose in-car breathalyzer has a track record of reliability.

RoadGuard Interlock has been in the business of providing customers with efficient, accurate, and easy-to-use interlock devices for over 20 years. For more information on our BAIIDs, please contact us.


*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.