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You may have heard that smoking can cause a “false positive” on an ignition interlock device (i.e., the device showing the presence of alcohol in a breath sample when it isn’t present). The fact is that smoking and vaping won’t cause a false positive but can affect the functionality of the device, causing ignition interlock device problems, and it’s worth knowing how.

How Do Ignition Interlock Devices Work?

An ignition interlock device is essentially a breathalyzer that is connected to your car’s ignition system. You blow into the mouthpiece attached to the ignition interlock device, and the device starts the car only if it detects that your breath is free of alcohol or below an established threshold. So, it would seem logical that smoking might cause ignition interlock device problems. However, it is not accurate that smoking or vaping can cause a false positive resulting in an ignition interlock violation where one does not exist, but device functionality may be impacted.

What Problems Can Smoking Actually Cause?

The biggest problem with smoking and ignition interlock devices is smoke entering the device. This can happen if you are actively smoking when you are performing the required test. You should never blow smoke into the ignition interlock. You also should not breathe into the device if you are vaping. Again, this won’t cause a false positive, but it can damage the interlock device by drying out the fuel cell (a sensor within the device that is essential to its proper operability). This damage can be caused by both tobacco and marijuana smoke.

This could lead to your provider having to replace the ignition interlock device prematurely, and you will be solely responsible for the costs of the replacement.

It’s unclear whether vapors exhaled from vaping into the device causes the same damage as smoking, mostly because it’s a newer trend and habit people are engaging in, but there’s definitely a risk that contaminants from vaping exhalation can build up inside the unit and impair the device’s functionality or operability.

Additionally, actively smoking or vaping can cause you to cough or choke as you blow into the device, which can force a retest.

What Should You Do if You Smoke or Vape and Have an Ignition Interlock Device?

Because of how ignition interlock devices work, you should take a few steps to make sure that smoking or vaping won’t cause the device to fail. In many cases, with modern devices, the device will require a retest. Some things you can do:

  1. Don’t attempt to blow into the device between puffs of smoking. This may cause the problems listed above.
  2. Take a few deep breaths before blowing into the device to clear any contaminants out of your mouth and throat.
  3. Ideally, wait fifteen minutes after putting anything in your mouth before using the device. This includes cigarettes and e-cigarettes, but also food, drinks, and medicine. Avoid using alcohol-based mouthwash right before driving.
  4. Rinsing out your mouth with water may also help.

If the device shows a failed test, you should be able to wait a couple of minutes and try again. The latest ignition interlock devices will simply show that they couldn’t get a sufficient reading. Draeger Interlock devices will guide you with step-by-step messaging on how to provide a correct breath sample. Of course, you want to provide a good breath test straight away so you can get on the road, which is why you should always stop smoking at least fifteen minutes before you intend to leave.

You should also avoid smoking or vaping in the vehicle. You should avoid consuming anything other than water while driving.

In sum, neither smoking nor vaping will create a false positive and, the primary reason to keep smoke and vape away from your ignition interlock device is to avoid ignition interlock device functionality problems caused by particles damaging the essential fuel cell sensor. If you have to have an ignition interlock installed, you can trust in Draeger Interlock. We can also give advice on best practices for proper ignition interlock device operation.

Still wondering how do ignition interlock devices work? Contact us today to find out more and learn what we can do for you.

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