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Ignition Interlock Device: What to Know

Required to install an ignition interlock device? Here's a general overview of how these devices typically work.

What the device generally does

An ignition interlock device is a breath-testing unit wired into a vehicle's ignition system. The driver must provide a breath sample below a set alcohol threshold before the car will start, and often periodically while driving.

When it's typically required

Requirements vary by state, but interlock devices are commonly required for repeat offenders, cases involving high test results, or as a condition of a restricted license that allows driving during a suspension period.

Installation and ongoing costs

Drivers required to use an interlock device generally pay for installation, monthly monitoring, and removal, and providers are typically state-approved. Costs and requirements vary by provider and state.

What happens if a test is failed

Failing a breath test on the device, or missing a required rolling retest, is typically logged and reported, and can result in penalties, including extending the required use period in some states.

How long it's usually required

Duration varies significantly based on your state, offense number, and case specifics — ranging from several months to multiple years in more serious or repeat cases.

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Frequently asked

Do I have to pay for the interlock device myself?
In most states, yes — the driver is typically responsible for installation and monitoring costs, though some states have limited assistance programs for financial hardship.
Can I remove the interlock device early?
Generally no, not before your state's required period ends, though some states allow early removal under specific limited circumstances.
General legal information for educational purposes only — not legal advice, and no attorney-client relationship is created. DUI/DWI consequences vary significantly by state and prior record; confirm details with a licensed attorney in your state.

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