What an Ignition Interlock Device Is and When It Applies

An Ignition Interlock Device (IID) is a breath-testing machine wired into your vehicle's ignition system. It requires you to blow into a mouthpiece before the engine will start. Whether you must install one depends on why your license was suspended — not on the suspension itself.

IIDs are required by law in most states only for suspensions tied to alcohol or drug-related driving offenses. If your license was suspended for unpaid tickets, points accumulation, medical reasons, or administrative violations, an IID is not legally required. The state that suspended your license determines the rule.

Some states mandate IIDs for a first DUI or DWI conviction; others require them only after a second offense or a refusal to take a breath test. A few states offer them as an alternative to a full suspension rather than as a requirement. The specifics depend on your state's law and the exact offense on your record.

Key Takeaways

  • Ignition interlock devices are required by law only for alcohol or drug-related driving offenses, not for other types of license suspension.
  • Your state's DUI or DWI laws determine whether an IID is mandatory, and requirements vary significantly from state to state.
  • Even if an IID is required, you typically cannot drive any vehicle without one installed — including borrowed or rental cars.
  • IID installation and monthly monitoring fees are your responsibility and range from $70 to $150 per month depending on your state and provider.
  • Failing an IID test or tampering with the device can result in license revocation, vehicle impoundment, or criminal charges.

State-by-State Requirements for DUI and DWI Suspensions

Most states require an IID for a first DUI or DWI conviction, but the timing and conditions vary. Some states impose the requirement when ready upon conviction; others delay it until after a mandatory suspension period ends. A handful of states allow you to install an IID as an alternative to serving the full suspension.

States that require IIDs for first-offense DUI include California, Colorado, Connecticut, Delaware, Illinois, Indiana, Maryland, Minnesota, Missouri, Nevada, New Hampshire, New Mexico, New York, Ohio, Oregon, Utah, and Virginia. However, each state sets its own timeline — some require installation within 30 days of conviction, others within 60 days.

States with more lenient first-offense rules include Georgia, Louisiana, and South Carolina, which may not require an IID for a first offense but do for a second or subsequent offense within a set period. A few states, such as Arizona and New Jersey, require IIDs even for first offenses in certain circumstances, such as a blood alcohol content above a specific threshold or a refusal to submit to a breath test.

If you were suspended in one state but now live in another, you must follow the law of the state that suspended your license, not your current state of residence. Contact the DMV in the state that issued the suspension to confirm the exact requirement.

How an IID Works and What Happens During a Test

When you start your vehicle, the IID prompts you to provide a breath sample. The device measures your blood alcohol content (BAC). If your BAC is below the legal threshold — typically 0.02 percent, which is lower than the 0.08 percent driving limit — the engine starts normally.

If your BAC is above the threshold, the engine will not start. The device logs the failed attempt and may trigger a horn or flashing lights. You must wait a set period (usually 15 to 30 minutes) before attempting another test. Repeated failed tests can result in a lockout that requires a technician to reset the device.

While driving, the IID may request a rolling retest — a breath sample taken while the vehicle is in motion. You have a set time (usually 5 to 10 minutes) to provide the sample at a safe location. Failing a rolling retest or not providing a sample triggers a violation that is reported to the court or DMV.

The device records all tests, attempts, and violations. A technician downloads this data during monthly service visits. The court or DMV reviews the data to monitor your compliance. Patterns of failed tests, missed service appointments, or tampering can result in license revocation or criminal charges.

Installation, Costs, and Length of Time You Must Use an IID

You are responsible for finding an IID provider and paying for installation and monitoring. Most states maintain a list of certified providers on the DMV website. Installation typically costs $100 to $300, depending on your vehicle and the provider. Monthly monitoring fees range from $70 to $150.

The length of time you must use an IID depends on your state and the offense. For a first DUI, most states require 6 to 12 months of use. A second or subsequent offense typically requires 12 to 36 months. Some states extend the requirement if you fail tests or miss service appointments.

You cannot remove the device yourself or have it removed early without court or DMV approval. Tampering with, disabling, or attempting to circumvent an IID is a separate criminal offense in most states and can result in additional fines, jail time, or license revocation.

If you own multiple vehicles, you must have an IID installed in each one you plan to drive. If you drive a borrowed or rental vehicle, that vehicle must also have an IID installed before you can legally operate it. This requirement applies even if the vehicle belongs to someone else.

What Happens If You Fail an IID Test or Miss a Service Appointment

A single failed IID test does not automatically result in license revocation, but the violation is recorded and reported to the court or DMV. One or two failed tests may be overlooked if your overall compliance record is strong. A pattern of failed tests — typically three or more within a monitoring period — triggers a violation notice.

When a violation is reported, the court or DMV may order you to appear and explain the failed tests. You may face a fine, an extension of your IID requirement, or suspension of your driving privileges. In some cases, a pattern of failures can result in permanent license revocation.

Missing a scheduled service appointment is also a violation. You are required to visit a certified technician monthly (or as directed by your state) to have the device serviced and data downloaded. Missing an appointment without rescheduling within a set timeframe — usually 7 to 14 days — can result in a violation report and potential license suspension.

If you cannot afford the monthly fees, contact your state's DMV or the court that ordered the IID. Some states offer fee reductions or waivers for low-income individuals. Failure to pay fees does not excuse you from the requirement; unpaid fees can result in additional fines and license suspension.

IID Requirements for Other Types of Suspension

If your license was suspended for reasons other than DUI or DWI — such as unpaid traffic tickets, accumulation of points, medical disqualification, or administrative violations — an IID is not required by law. However, you cannot legally drive on a suspended license regardless of whether an IID is installed.

Some drivers mistakenly believe that installing an IID will allow them to drive on a non-alcohol-related suspension. It will not. An IID only addresses the specific condition of an alcohol-related suspension. Installing one does not restore your driving privileges for other types of suspension.

If you have both an alcohol-related suspension and a separate suspension for another reason, you must resolve both issues. You may need to pay outstanding fines, complete a defensive driving course, or obtain medical clearance before your license is reinstated. The IID requirement applies only to the alcohol-related portion of the suspension.

Driving on a Suspended License Without an IID When One Is Required

Driving on a suspended license is illegal in all states. If your suspension requires an IID and you drive without one installed, you are committing a separate offense beyond the original suspension violation. Penalties typically include fines ranging from $500 to $2,000, jail time of 10 to 90 days, or both.

Law enforcement can identify an IID violation through a traffic stop, vehicle inspection, or court records check. If you are stopped and your license shows an active IID requirement, the officer will verify whether the device is installed. Driving without it is grounds for arrest and vehicle impoundment.

A conviction for driving on a suspended license with a required IID can result in an extended suspension, additional criminal charges, and a permanent mark on your driving record. Some states treat it as a felony if you have prior convictions. Your insurance rates will increase significantly, and some insurers will cancel your policy entirely.

Frequently Asked Questions

Can I drive someone else's car if I have an IID requirement?

No. You cannot legally drive any vehicle without an IID installed if one is required by your suspension. This includes borrowed cars, rental vehicles, and company vehicles. The vehicle must have a certified IID installed before you can operate it, regardless of who owns it.

What if I cannot afford the monthly IID fees?

Contact the DMV or the court that ordered the IID and ask about fee reduction or waiver programs. Some states offer reduced fees for low-income individuals. You can also ask about payment plans. However, inability to pay does not excuse you from the requirement; you must still maintain the device or face additional penalties.

Do I need an IID if my license was suspended for unpaid tickets?

No. An IID is required only for alcohol or drug-related driving offenses. If your suspension is for unpaid tickets, points accumulation, or other non-alcohol reasons, an IID is not legally required. However, you still cannot drive on a suspended license.

Can I have the IID removed early if I pass all my tests?

No. You must keep the IID installed for the full period ordered by the court or DMV, even if you pass every test. Early removal requires a court order or DMV approval. Contact the court or DMV that ordered the device to request early termination; approval is rare and typically requires a formal hearing.

What happens if I move to a different state while my IID is required?

You must continue to comply with the requirements of the state that suspended your license. If you move, contact that state's DMV to report your address change and confirm whether you can transfer your IID requirement to your new state. Some states have reciprocal agreements; others do not. Failure to comply with the original state's requirements can result in additional penalties.