Attorney at Law

Ignition Interlock Device

James Parker
February 16, 2022

What Is an Ignition Interlock Device?

An ignition interlock device is a mechanism which prevents a vehicle from starting unless the device is disengaged. Ignition interlock devices are disengaged by breathing into the mouthpiece of the device in order to prove that they are not intoxicated. These devices are connected to the ignition system of the vehicle and will not allow the vehicle to start if they detect alcohol.

Ignition interlock devices are typically composed of four main components: the tv remote sized handheld unit, the mouthpiece for recording tests, the relay cord connected to the ignition control system, and sometimes a camera. These devices must be installed at a licensed center and state law mandates that they be calibrated every 30-90 days depending on the state. This center may also be responsible for overseeing the monitoring capabilities of the device.

Ignition interlock devices require two kinds of tests: start tests and rolling tests. Start tests are required in order to ignite the engine and begin operation of the vehicle. Failing a start test will result in the vehicle being inoperable for a set period of time. Rolling tests are tests that must be periodically performed while the vehicle is in motion. Typically, the device will beep at the user, informing them that they have approximately 5 minutes to submit a breath test using the device. If a rolling test is failed, the vehicle will not be disabled but the results or failure to submit will be reported to the department of motor vehicles.

Not all ignition interlock devices function the same. In general there are three ignition interlock test types: breathing tests, exhale tests, and hum tests. Breathing tests require the driver to exhale for two seconds, inhale, and then exhale again for another two seconds. This method is considered to be highly accurate and more straightforward than other methods.

The exhale test requires a single, forceful, sustained exhale in order to submit a breath sample. This can be difficult to manage in some situations but is still a relatively straightforward test with accuracy that falls comparatively since it is a single breath compared to more sustained tests.

Hum tests are the most complex of the ignition interlock test varieties. This test requires the user to first exhale, then hum into the mouthpiece for a period of time. This test is sometimes criticized for being overly complex, leading to lockouts even if the driver is not intoxicated.

Key Takeaways

  • An ignition interlock device is a mechanism that prevents a vehicle from being started unless the user first submits to and passes a breathalyzer test. 
  • An ignition interlock device can be required as part of a punishment for DUI.
  • If a court requires a defendant to get an ignition interlock device, it must be fused into the engine of any vehicles that the defendant drives or uses, at the expense and inconvenience of the defendant.
  • If you are facing the possibility of being compelled to install an ignition interlock device as the result of a DUI charge, an experienced DUI attorney may be able to improve the outcome of your case by leveraging experience and expert testimony.

Ignition Interlock Devices and Driving Under the Influence (DUI) Charges

Ignition interlock devices are one of the many penalties assigned by DUI charges if the defendant is found guilty. They are inconvenient, expensive, and vulnerable to key errors that can strand a driver for hours. 

Ignition interlock devices function by taking breath samples. This means that they are susceptible to the same errors as a breathalyzer. Any kind of contaminants in the mouth including stomach acid or gum with sorbitol can register as a false-positive and since the device will require rolling tests, if a driver is chewing gum when the test is required, the DMV may receive a false-positive result. 

In addition to the issues in accuracy, an ignition interlock device can be a costly burden that the defendant must bear. While the initial ignition fee can range between $50 - $150, there is also the monthly leasing costs for the device that can be as expensive as the full installation. With ignition interlock requirements ranging from six months up to five years, leasing an ignition interlock device could cost over $9000 over the course of the duration. Additionally, even when the period of requirement is over, the driver will have to pay up to an additional $150 to have the device removed from their vehicle. 

What’s more, the conditions of a DUI charge are that this device must be installed on all vehicles that the driver owns or routinely operates. This means that for a household with multiple vehicles, the cost of installing and maintaining multiple ignition interlock devices can compound quickly. If the convicted driver does not install these devices, or if they use a vehicle that does not have an ignition interlock device to circumvent the court’s orders, they may face additional fines and penalties.

Bottom Line

An ignition interlock device can be an inconvenient, expensive, embarrassing reminder of a past mistake that is bound to you and everyone else who uses your vehicle. In order to ensure that this future blight is avoided, contact an experienced DUI attorney.

A DUI attorney can help to mitigate the worst of a DUI charge if not get it dismissed entirely. If they are unable to get the charges dropped outright, an experienced DUI attorney can trade the requirement of an ignition interlock device for something less expensive, like community service, or something more confidential, like safe driving classes.

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