Ignition interlock devices: requirements, costs and insurance

Whether you need an ignition interlock after a DUI depends on your state, your test result and whether it is your first offense. Some states require a device for every offender, some only for repeat offenders or high test results, and a few require none by statute. The driver pays for the device, the monitoring and the removal. The insurance consequence comes mostly from the DUI conviction and the SR-22 or FR-44 filing that often travels with it, not from the device itself.

What an interlock is and how it works

An ignition interlock device is a breath-testing unit wired to the vehicle's starter. You blow into it before the engine will start. Washington's Department of Licensing describes it as an instrument you blow into "before you can start your vehicle," and says it starts the vehicle only if your breath alcohol is under .025 (Washington DOL). Devices also ask for retests while you drive and log each result for a service provider to report to the state. Thresholds differ by state, so the .025 figure is one example, not a national rule.

An interlock is not a type of license or a type of insurance. It is a condition attached to a license, a sentence, or both. That is why the same driver can hear it described as a court order, a licensing requirement and an insurance matter in the same week.

Who has to install one: a state-by-state patchwork

The Insurance Institute for Highway Safety (IIHS) keeps a table of state laws; the version consulted for this article is dated November 2026 (IIHS). It sorts requirements into three situations: driving during an administrative suspension that follows an arrest, driving during a suspension that follows a conviction, and a penalty or condition for reinstating a license. Within each, it separates first offenders from repeat offenders. The IIHS says laws that require interlocks for all impaired-driving offenders reduce alcohol-involved crashes.

A few rows show how far states differ:

The table's footnotes show a second pattern: incentives. Arizona, California, Louisiana and Missouri remove the mandatory "hard" suspension period if the offender chooses to install a device. Maine significantly shortens the suspension. Virginia lets a driver reduce a post-conviction interlock or restricted-license period by installing one voluntarily before trial, and North Carolina lets courts reduce a sentence if the driver installs one within 45 days of being charged. New Jersey allows a driver to avoid the post-conviction fine and reduces licensing action if the device is installed at the time of arrest, a provision the IIHS lists as in force until January 1, 2029.

Some rules carve out exceptions. Arkansas requires a device for a first offender unless the offender drives an employer's vehicle for work, cannot provide a deep lung breath sample, or lives more than 100 miles from a provider. Pennsylvania, effective November 22, 2027, will not apply its reinstatement interlock requirement to a person with no prior offenses who certifies that they do not intend to operate a vehicle during the interlock period.

States change these laws often, and the table says it is "not guaranteed to be current." Use it to see the shape of the rules, then confirm yours with your state motor vehicle or licensing agency, or with the state car insurance requirements lookup tool to find the right regulator. A DUI timeline: from arrest to getting insured again shows where the device fits in the sequence from arrest to reinstatement.

How long the requirement lasts

The length is set by the state and often by the judge. Washington is a useful example because its agency publishes the periods. For a DUI or physical-control conviction, or a deferred prosecution, the interlock requirement is:

The court may require a longer period. Two features change how the time is counted:

• Tolling. Washington's rule gives day-for-day credit for each day a device is installed, and the clock stops if the device is removed, tampered with or no longer compliant. Remove it early and the license can be suspended and the period restarted.
• A clean ending. To get a certificate of compliance, you must go the last 180 consecutive days (for convictions on or after July 23, 2017) without a start attempt at .04 or more, a failed or missed retest, or a missed service appointment. A violation restarts that 180-day window.

A medical exemption exists for drivers who cannot physically blow into the unit; in Washington it lets the driver earn tolling credit without a device installed, but not drive.

What it costs, and who can get help

The driver pays. Washington's agency lists the costs as installing, leasing and removing the device, maintaining proof of financial responsibility, a license application fee, and a monthly state fee that funds help for low-income drivers (Washington DOL). Prices are set by vendors, within whatever limits the state imposes. Tennessee is one state that publishes its caps. As of the state's page last updated in February 2024, under its program rules (Tennessee Ignition Interlock Program):

• Installation: no more than $75 an hour with a three-hour maximum.
• Leasing, monitoring and maintenance: no more than $125 a month.
• Removal: no more than $75.
• Resetting a device locked out after five or more violations: no more than $50.
• A temporary lockout code: no more than $25.
• An annual administrative fee of $12.50 for each new user, collected at installation and each year after.

These are ceilings, not typical prices. A vendor can charge less.

A worked example. The figures are the Tennessee caps, applied to an invented case. Suppose a driver has a 12-month requirement and a vendor charging right at every cap. Installation takes three hours, so $225. Twelve months of leasing and monitoring at $125 is $1,500. Removal is $75 and the administrative fee is $12.50. The total is $1,812.50, about $151 a month. A five-year requirement at the same monthly rate would be $7,500 in lease and monitoring fees alone. That is why the length of the order matters as much as the daily price. These totals leave out the SR-22 premium and court costs, and a vendor charging half the cap would cost half as much.

Help paying. Programs differ. In Washington, an approved low-income driver gets reimbursement to the provider of $80 per month for each service (installation, monthly lease, removal or transfer to another vehicle), and the driver pays the rest. Applicants must be indigent as defined by state law and under a federal poverty guideline: for one person in 2026, the page lists annual income of $19,950. Approval lasts a year, then you reapply. In Tennessee, a driver who asserts to the court that they cannot afford the device gets a hearing on financial ability, and a driver declared indigent cannot be refused service while money remains in a state indigency fund. Ask the court, the agency or your vendor which program your state runs, and apply before the first monthly bill arrives.

How the device fits with your car insurance

An interlock is not an insurance product, and none of the agency pages cited in this article says it changes a premium. The cost arrives through three other paths.

1. The conviction. The DUI is a major violation on your record, and your insurer rates it. See Car insurance after a DUI. A regulated example: North Carolina's schedule gives driving while impaired 12 insurance points and a 340% rate increase (North Carolina Department of Insurance). Most states leave the figure to insurers.
2. The financial responsibility filing. Washington requires proof such as an SR-22 to get an ignition interlock license. In Florida and Virginia, a DUI conviction brings an FR-44 with higher limits: Florida's statute sets $100,000 per person, $300,000 per crash and $50,000 for property damage for at least three years (Florida Statutes 324.023, 2025), and Virginia sets limits double those of its SR-22 (Virginia DMV). Higher limits cost more. See SR-22 insurance explained and FR-44 insurance in Florida and Virginia.
3. The insurer's decision to renew. A conviction can lead to nonrenewal. See Nonrenewal after a ticket or DUI: your rights and next steps.

If the filing lapses while you hold an interlock license, the license can be suspended again. What happens if your SR-22 policy lapses or is cancelled covers that.

If you do not own a car but must show insurance, a non-owner car insurance policy can carry the filing. Note the practical limit in Washington: an interlock license requires a device in "all vehicles you drive," so you still need a vehicle with a device installed, and its owner's agreement, to drive anything.

Failed tests, violations and tampering

A device records every breath test, and a vendor reports violations to the agency at service visits. What counts as a violation, and what follows, is set by state rule. Washington's list shows the usual categories. Each of the following restarts the 180-day clean period needed for a certificate of compliance:

• Trying to start the vehicle with a breath alcohol of .04 or more.
• Failing to take, or failing, a required random retest.
• Missing a scheduled maintenance, calibration or inspection appointment.

Beyond that, Washington adds 180 days to the requirement for a conviction of driving with a broken device or no device, and for a conviction or notification of circumventing the device by tampering, disabling or bypassing it. Tennessee's published fee rules suggest the practical side: they set a fee ceiling for resetting a unit that has gone into permanent lockout after five or more violations and for a temporary lockout code. A lockout is a service call and a fee. Repeated violations are a reportable record.

Having another person blow into the unit is the classic way to defeat it, and states generally treat that as circumvention. Do not do it; the consequence can be a longer requirement and new charges, not just a service fee.

Borrowing a car, sharing a car and employer vehicles

The restriction follows the driver, not a single car. In Washington, a driver on an interlock license must maintain a device on all vehicles they drive. The agency's own words on the point are clear, and the practical effects follow:

• Borrowed cars. Driving a friend's or relative's car without a device violates the restriction. If you must use another vehicle, the device has to be installed there first. The owner has to agree, and the cost is yours.
• Household cars. If the family has two cars and you drive both, both need a device. Other people can still drive them, but anyone starting the car must pass the same test, which is a practical burden for a household. Ask the vendor how the unit handles other drivers' tests.
• Moving a device. Transferring a device from one car to another counts as a service, and in Washington it is one of the services the low-income program reimburses.
• Work vehicles. Washington lets an employer sign a declaration so that the driver can drive an employer-owned vehicle during work hours without a device, for up to a year, with limits: the exemption does not cover a vehicle assigned to you for commuting, it is not available for self-employment unless the vehicle is used only for work, and you may not drive a commercial motor vehicle at all while holding the interlock license.
• Insurance on someone else's car. The owner's policy covers permitted drivers according to its terms, and the owner should ask the insurer how a household member's DUI and an installed device are treated. See permissive use and household member for the terms. Some insurers exclude a driver; if so, you cannot drive the car at all.

Getting a restricted license with the device: steps

The exact order depends on your state. In outline:

1. Read the order and the agency notice. Find out whether the device is required by the court, by the agency or both, and for how long.
2. Choose an approved vendor. States publish lists. Washington points to its State Patrol's approved manufacturers. Compare the monthly price, the service-center distance and the lockout policy.
3. Get the SR-22 or FR-44 issued if your state requires it for the restricted license. Confirm that the state received it.
4. Install the device in every vehicle you will drive. The vendor sends proof of installation to the agency.
5. Apply for the restricted license and pay the fees. In Washington, the agency denies an application if documents are not all received within 30 days.
6. Attend every service visit. Missing one can reset your compliance period.
7. Request the certificate of compliance from the vendor when the period ends, and ask the agency to remove the notation from your record.

Questions to ask before you sign

For the vendor:

• What are the installation, monthly, removal and early-termination fees, and which are capped by the state?
• What happens at a lockout, and how far is the nearest service center?
• Is the unit camera-equipped, and how are other drivers of the car handled?
• Who reports violations, and how do I see my record?

For your insurer or agent:

• Will you file the SR-22 or FR-44 for this state, and for how long?
• How does the policy treat me as a driver of the household's other cars?
• If the filing lapses, how fast will the state be notified?

Common questions

Can I get the interlock removed early?

Only as your state allows. In Washington, removing it before the period ends can suspend the license and restart your compliance period.

Does the interlock lower my insurance rate?

None of the agency sources used here says so. The premium reflects the conviction and the filing. Ask each insurer directly, because plans differ.

Do I need an interlock if I do not drive?

Often yes, as a condition of reinstatement or the sentence. Some states have a carve-out: Pennsylvania's table footnote describes one beginning in November 2027 for a first offender who certifies that they will not operate a vehicle. See the IIHS table.

What if I move to another state during the requirement?

Check with both states, because the new state will have its own rules. Washington's page, for example, explains how an out-of-state vendor reports an installation and its compliance status to the agency. See A DUI timeline: from arrest to getting insured again for the general sequence.

Does this apply to drug-related DUI?

Some states do. Washington's agency lists a DUI or physical-control conviction involving drugs or alcohol among the triggers, although the device measures breath alcohol only. See Drugged driving: marijuana, prescriptions and DUI insurance.

Key takeaways

• Interlock requirements range from none to every offender. The IIHS table (November 2026) shows Alaska, Hawaii, Kansas, New Mexico, Oklahoma and Washington requiring them in every situation and Indiana, North Dakota and Wisconsin in none.
• The driver pays for installation, monthly leasing and removal. Tennessee's caps show how the totals add up, and some states offer help for low-income drivers.
• A failed retest, a missed service visit or tampering can extend the requirement, restart a compliance period or lead to new penalties.
• The insurance effect comes from the DUI conviction and the SR-22 or FR-44 filing, not from the device. Keep the filing policy continuous.
• The restriction follows you into every vehicle you drive, so plan for borrowed cars, household cars and work vehicles before you need them.