Circumventing an Interlock Device

May 9, 2019

An interlock device, also known as a car breathalyzer, is often installed via state mandate for any driver that has been charged with driving under the influence (DUI) or driving while intoxicated (DWI). While there are a variety of different interlock devices, Low Cost Interlock is the premium provider of interlock devices, currently in 14 states.

The key thing to know about an ignition interlock device is that attempts to circumvent the device may result in penalties or fines, including loss of license and/or additional charges on your criminal record. That said, some people still attempt to circumvent an ignition interlock device by taking measures to try and “beat the system.”

Below, we’ll discuss the various methods and the potential ramifications for such actions.

Why Do I Have an Ignition Interlock Device?

Before we begin, it is essential to understand why interlock devices are installed in the first place. If you have been charged and convicted of driving while under the influence, there is a broad consensus that offenders are likelier than the general public to repeat the poor decision of drunk driving. Therefore, the device serves 3 primary purposes:

  • To keep unsafe drivers who are intoxicated from operating a motor vehicle and the roads safe for other drivers.
  • To protect alcohol users from their own bad decision making.
  • To assist offenders in repaying their debts to society so that they can be back behind the wheel with no enforcement devices… after they have regained the trust of the state.

There is a bar of safety that is assumed to be cleared by any individual who is driving with an ignition interlock device. By definition, if the vehicle’s engine is running, then the driver has successfully operated the ignition interlock device and can be safely assumed to be sober.

How to Operate an Ignition Interlock Device

Now, before we can go over ways that people attempt circumvent interlock systems, it is critical to understand how they function. Ignition interlock devices are relatively simple to operate. They are designed to prevent the engine from starting if the driver has alcohol on their breath. To start the vehicle, the driver must simply blow into the device and pass the blood alcohol test, which in most interlock devices’ case is providing a breath sample with less than 0.03% BAC.

Operating the Device

To operate the device, the driver must blow into the breathalyzer for some predetermined amount of time, usually a few seconds, to give a proper sample. Some interlock devices require a pattern of breathing including humming, sucking, and/or blowing, but Low Cost Interlock devices only require a 3 second exhale. Every interlock device will also require a rolling retest within 10 minutes of the initial test, where the driver must once more provide a sample that proves they are sober and able to continue driving their vehicle.

If a driver fails to perform a rolling retest when prompted to do so, or if the driver fails the breathalyzer test, then the vehicle device will begin to sound an alarm and flash the car’s lights. As a general note, there is no feature on the device that automatically shuts the engine off because that would be dangerous to the driver and other people sharing the road.

Circumventing an Interlock Device

Now that we’ve covered that vital information, we can now discuss the various methods that people use to try and circumvent their interlock device.

Having a Sober Person Blow into the Device

Some people attempt to have a sober person blow into their interlock device as a means of getting around the initial test. While this might work initially, it would pose a problem as soon as the rolling retest kicks in. To prevent this, certain states, namely Washington and Virginia, require that ignition interlock devices be installed with cameras. These cameras are not taking video, but rather taking photographs each time that the user blows into the device to give a sample.

The purpose of these cameras is to be sure that no other person besides the driver is blowing into the device and causing the test to “pass” when it should fail. This is not a viable way to cheat an ignition interlock device. If the passengers are sober and the driver is not, then it should be the sober person driving the vehicle. Fortunately, cameras are one of the ways that states have ensured that there are fewer possible methods of cheating an ignition interlock device.

Other Methods of Cheating

On older models of ignition interlock devices, there may have been some ways to cheat the system. In the past, people attempted to:

  • Hotwire the vehicle
  • Cut the wires in the ignition interlock devices
  • Install a “bypass” device
  • Deactivate the device after installation

In the newest ignition interlock devices, however, including the Low Cost Interlock device, these methods of cheating do not work. This is due to the variety of safety measures put in place by engineers to prevent such actions or tampering.


Ignition interlock devices come calibrated when they are installed, meaning that they are “set” to a certain standard in order to detect alcohol on the breath. The standard measurement is .03% blood alcohol content in order to pass the breath test and start the vehicle.

Over time, the ignition interlock device can become less calibrated for a variety of reasons:

  • Exposure to heat
  • Exposure to humidity
  • Use and re-use
  • Rust or condensation in the components of the device

To prevent such things from occurring, the devices must be recalibrated from time to time, typically once every 30 to 60 days. To ensure their accuracy, ignition interlock providers are legally required to calibrate the device periodically. With Low Cost Interlock, the device will alert you when your calibration appointment is approaching. Failure to attend can result in an interlock violation, extension, and vehicle lockout.


While “hotwiring” the vehicle may seem like an attractive alternative to performing the necessary steps with the ignition interlock device, in reality, it is an awful idea. First, most interlock devices are installed “below” the point in the system where hotwiring must occur. In other words, you might hotwire your vehicle and still need to blow into the device to get the ignition started.

This attempted method of cheating is not a smart one. If you tamper with and damage the ignition interlock device itself, you’ll be liable for damages to the device and might be charged with a crime. If you damage your vehicle, you could reduce its value and ultimately end up hurting yourself.

Dangers of Drunk Driving

If you have been charged with driving under the influence or driving while intoxicated, you are likely aware of the numerous consequences of such an action. It is true that if you drive under the influence of alcohol, you could:

  • Injure yourself
  • Injure others
  • Damage your vehicle or other property of yours
  • Damage other people’s property, including vehicles
  • Kill yourself or others by driving recklessly

There are no good reasons to drive while under the influence of alcohol. If you are considering drinking and driving, please reconsider. Circumventing the ignition interlock device on your vehicle is also extremely unwise, and there are a variety of consequences for those who attempt to do so.

Consequences of Trying to Circumvent your Interlock Device

Ignition interlock devices are meant to prevent you from driving under the influence of alcohol. They are intended to keep you safe, to prevent damage to property and other financial losses, and to protect your motoring neighbors and pedestrians. For this reason, there are a variety of consequences for tampering with or trying to circumvent your ignition interlock device:

  • Extended Period with Interlock Device You could be ordered by the court to keep your ignition interlock device for a longer period of time than you would otherwise need to.
  • Loss of Restricted License – In all likelihood, if you have an interlock device, you have also been given a restriction on your license. This license could get taken away if you try and circumvent the device itself, leaving you unable to drive at all.
  • Loss of License Permanently – If you are convicted of additional charges, you could lose your license to operate a vehicle permanently.

Additional DUIs

One additional factor that many people fail to consider when googling “how to circumvent your ignition interlock device” is that if you do succeed in circumventing the device, you may be setting yourself up for additional DUI charges.

The embarrassment of having gone through the trouble of cheating your device and then receiving another DUI charge should be enough to keep anyone from trying to “cheat the system.” However, there is one other significant reason why you should not even attempt to cheat; if caught and given an additional DUI, that might result in the requirement of an interlock device on any vehicle you operate for life.

This, of course, is not even taking into consideration the lives one puts at risk when driving on the roads while intoxicated.

Jail Time

In addition to all these reasons, if you have a history of drunk driving violations, you could be sent to jail. Driving with an interlock device on your vehicle is intended to prevent you from causing danger to yourself and others, but it is also designed with your long-term future in mind. No one wants to go to jail, saying it is not a pleasant experience would be putting it lightly. This device is a helpful tool to prevent you from making bad decisions after you’ve had your judgment severely hampered by alcohol.

Failing an Ignition Interlock Device Test

There is typically only one reason why a person would fail an ignition interlock device. That reason, of course, is that they have been drinking. While there are a very limited number of reasons beyond drinking alcohol that could cause a failure, they do exist. There are some foods and other items that do contain trace amounts of alcohol.

For example:

  • Breath mints
  • Breath sprays
  • Spicy gums, such as Dentyne or Trident
  • Mouthwash
  • Some types of medications, especially liquids like NyQuil

The Bottom Line

After reviewing all the methods you could try to cheat the ignition interlock device, the bottom line is this: there’s simply no good way to circumvent an interlock device. While you may think your situation is special or unique, the interlock device has been installed for a reason. It is there to protect you from harming yourself and others by drinking and driving.

As discussed, all of the methods above inevitably fail, including:

  • Tampering with the device
  • Bypassing the device
  • Hotwiring the vehicle
  • Having another person blow into the device

There’s no good reason to try to cheat, and even if there was, it’s not possible!


Dickinson, M. National Center for Biotechnology Information. A Comparison of First Time and Repeat Rural DUI Offenders. Retrieved from

CA.Gov. Ignition Interlock Devices. Retrieved from

Drug & Alcohol Solutions. Substances That Can Affect a Breath Test. Retrieved from

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