License and SR-22
Ignition Interlock Devices: When They're Required
When Is an Ignition Interlock Required After a DUI?
An ignition interlock is a breath-testing device wired to your car that keeps it from starting if it detects alcohol, and most states use it in DUI cases. Some states require one after every first offense (New Jersey, Washington, New Mexico), some only at a high BAC such as 0.15 or more (Wisconsin, Florida, North Carolina), and some leave a first offense to the court. Repeat offenses bring longer terms almost everywhere, up to life in a few states. Check your state with the SR-22 and interlock lookup.
What Is an Ignition Interlock?
An ignition interlock is a small breath-testing device wired into your car’s ignition. Before the engine starts, you blow into it. If it reads alcohol at or above its set point, the car won’t start. Once you’re driving, it asks for more samples along the way.
States set the details in law. The common set point is 0.02. Washington’s devices are set at 0.020 (Wash. Rev. Code § 46.20.720), New Hampshire’s block starting at 0.020 or more, Vermont’s lock the vehicle at 0.02 or more, and Virginia’s block starting above 0.02 and require rolling retests while you drive (Va. Code § 18.2-270.1). Some programs add more. DC requires a device with a camera, a lockout level of 0.020 and at least 20 tests per 30 days.
The device also keeps a log. That record is how the state checks your compliance, and it’s why a missed retest or a high reading can extend your time.
When an Ignition Interlock Is Required for a First DUI
This is the question most people searching “DUI interlock” want answered, and it depends heavily on the state. First-offense rules fall into four rough groups:
| Approach to a first offense | Examples |
|---|---|
| Required after every first offense | New Jersey, Washington, New Mexico (1 year), Nevada (185 days), Oregon (1 year after the suspension), South Carolina (6 months), Delaware, DC |
| Required for a first offense with high BAC or aggravating facts | Wisconsin (0.15 or more, or a refusal), Florida (0.15 or more, or a minor under 18 in the car), North Carolina (0.15 or more), Minnesota (0.16 or more), Michigan (0.17 or more), Missouri (0.15 or more, property damage or injury), Wyoming (0.15 or more) |
| Required only if you want to drive during the suspension | Kentucky (the interlock license is the only way to drive during an alcohol-based suspension), Maine (optional early reinstatement after 30 days), Vermont (optional interlock license during the suspension), Hawaii (needed only to drive during revocation) |
| Up to the court | California (up to 6 months for a first DUI under § 23152), Indiana, Montana, Ohio |
Even in the “required” group, the length varies. New Jersey ties it to BAC: 3 months for 0.08 to under 0.10, 7 months to 1 year for 0.10 to under 0.15, and 9 to 15 months after a 4- to 6-month forfeiture for 0.15 or higher or drugs. Arizona requires 12 months for a first alcohol DUI, which may end after 6 months if conditions are met, and 18 months for a first super extreme DUI at 0.20 or more (Ariz. Rev. Stat. § 28-3319). Colorado requires 9 months for a first offense below 0.15 and 2 years at 0.15 or higher.
North Dakota and South Dakota rely mainly on the 24/7 sobriety program, with twice-daily breath tests or electronic monitoring, rather than mandatory interlocks.
Know your BAC result. In many states it decides whether an interlock applies at all. The BAC guide explains the enhanced thresholds, and the first DUI guide covers the rest of a first-offense sentence.
Repeat Offenses Mean Longer Terms
For a second or later DUI, most states require an interlock, and the terms climb steeply.
- Two to three years for a second offense is common: Alabama (2 years), Colorado (2 years), Massachusetts (2 years on every vehicle), New Mexico (2 years), Oregon (2 years after the suspension), South Carolina (2 years).
- Five years or more after a second offense in Illinois (at least 5 years on all vehicles you own) and Washington (at least 5 years after a prior restriction).
- Ten years in Kansas for a fifth or later offense, Minnesota with three or more priors, Washington after two prior restrictions, and Mississippi for a fourth or later offense.
- Life for a fourth or later offense in New Mexico (you may ask a district court to remove it every 5 years), South Carolina and Wyoming (removal may be requested after 5 years).
Repeat cases often overlap with felony DUI. The felony DUI guide covers lookback periods and felony thresholds.
The table below lists every state’s first-offense and repeat-offense interlock rules.
Choosing an Interlock Before Your Case Ends
You don’t always wait for a conviction. Several states let you choose an interlock early, often to cut down or replace the time you’d spend with no license at all.
- Alabama: for a first offense without aggravating facts, an interlock is optional for 90 days to stay the suspension.
- Maryland: the administrative election runs 180 days for a test of 0.08 to 0.14, and 1 year for 0.15 or more or a refusal.
- Kentucky: you can apply to the Transportation Cabinet any time, even before conviction, and the court must require a repeat offender to apply during a pretrial suspension.
- Indiana: a court may order an interlock before trial as an alternative to suspension, and the time is credited toward the suspension.
- Rhode Island: on request, a mandatory suspension is reduced by imposing an interlock or testing. A first offense means at least a 30-day suspension plus 3 months to 1 year on the device.
Refusing the test usually lengthens the interlock term where one applies. In Colorado any refusal brings 2 years, and in Maryland a refusal election runs 1 year. The implied consent guide covers refusal penalties. An early election can also affect your administrative hearing, so check the deadline and get legal advice first.
First Offense by State
| State | First offense |
|---|---|
| DUI law in Alabama | 1 year if you refused testing, had a BAC of 0.15 or more, had a child under 14 in the vehicle, or someone else was injured; otherwise optional for 90 days to stay the suspension |
| DUI law in Alaska | at least 6 months after you regain the privilege to drive |
| DUI law in Arizona | 12 months for a first DUI involving alcohol (may end after 6 months if conditions are met); 18 months for a first super extreme DUI (0.20+) |
| DWI law in Arkansas | Yes, for alcohol DWI: an interlock for a period equal to the license suspension before reinstatement |
| DUI law in California | Court may order up to 6 months for a first DUI under § 23152; mandatory 12 months for a first DUI causing injury under § 23153; an interlock is also a condition of the first-offense restricted license |
| DUI law in Colorado | 9 months for a first offense with BAC below 0.15 (runs concurrently with the 9-month revocation); 2 years with BAC 0.15 or higher |
| DUI law in Connecticut | Yes. Required before restoration for all alcohol-related suspensions: 1 year after restoration on a first conviction; 6 months (21 or older) or 1 year (under 21) on a first failed-test suspension; 1 year on a first refusal. The longer period applies. |
| DUI law in Delaware | Yes. Mandatory for all first offenders regardless of BAC for offenses on or after February 1, 2015. First offenders election: at least 4 months on the IID license. First conviction: at least 12, 17 or 23 months depending on BAC. |
| DUI law in District of Columbia | Yes, for D.C. license holders: 6 months after a first DUI conviction; 1 year after a first refusal |
| DUI law in Florida | discretionary for at least 6 continuous months with BAC 0.08 or higher; mandatory for at least 6 continuous months if BAC was 0.15 or higher or a person under 18 was in the vehicle |
| OVUII law in Hawaii | Ignition interlock on all vehicles operated during the 1-year to 18-month revocation period |
| DUI law in Idaho | Yes: installed within 10 days after the 30-day absolute suspension ends and kept until 1 year after the suspension period ends; an administrative suspension (failed test) also requires an interlock for 1 year after the suspension ends |
| DUI law in Illinois | required to drive on a monitoring device driving permit during a first offender's summary suspension; the MDDP can be declined |
| OWI law in Indiana | not mandatory by statute; the court may order it as a condition of specialized driving privileges or, before trial, as an alternative to suspension |
| OWI law in Iowa | required for a temporary restricted license after a first offense |
| DUI law in Kansas | yes, after the 30-day suspension: 180 days of interlock-only driving (1 year with certain driving-record history, or 1 year after a 1-year suspension at BAC 0.15 or more) |
| DUI law in Kentucky | not mandatory; an ignition interlock license is the only way to drive during an alcohol-based DUI suspension and can shorten the suspension to 4 months |
| DWI law in Louisiana | as a probation condition: no driving for at least 6 months unless the vehicle has an interlock; required during the whole suspension at BAC 0.20 or more, and for a restricted license during a 0.15+ suspension |
| OUI law in Maine | not required; optional early reinstatement after 30 days of a first-offense suspension if an approved device is installed for the remaining suspension |
| DUI law in Maryland | yes: a DUI or DWI conviction or probation before judgment requires participation in the Ignition Interlock System Program (6 months the first time required) |
| OUI law in Massachusetts | not required by statute; may be ordered on a first-offense hardship license when blood alcohol was 0.15 or more |
| OWI law in Michigan | required on the restricted license after a first conviction with BAC 0.17 or more; otherwise the court may order it as a condition of probation |
| DWI law in Minnesota | required to regain driving privileges after a first offense at 0.16 or more (otherwise at least 1 year without a license) |
| DUI law in Mississippi | not mandatory; an interlock-restricted license is an alternative to the 120-day suspension when ordered by the court, and alcohol nonadjudication requires 120 days on an interlock-restricted license or a 120-day suspension |
| DWI law in Missouri | for reinstatement after a first conviction if BAC was 0.15 or more or there was property damage or personal injury; also a condition of the restricted driving privilege after a first administrative suspension |
| DUI law in Montana | discretionary: the court may order it |
| DUI law in Nebraska | yes: a first offender must apply for an ignition interlock permit and use a device for the revocation period |
| DUI law in Nevada | yes: 185 days |
| DWI law in New Hampshire | required for aggravated DWI (12 months to 2 years after the revocation ends) and for any limited driving privilege; not required by statute for a basic first offense |
| DWI law in New Jersey | yes for every first offense: 3 months (0.08 to under 0.10), 7 months to 1 year (0.10 to under 0.15), 9 to 15 months after a 4- to 6-month forfeiture (0.15 or higher, or drugs) |
| DWI law in New Mexico | yes: 1 year after a first conviction |
| DWI law in New York | yes for a misdemeanor or felony DWI conviction: at least 12 months as a condition of probation or conditional discharge (can end after 6 months of proven installation unless the court orders longer) |
| DWI law in North Carolina | only if BAC was 0.15 or more: for 1 year after restoration from a 1-year revocation |
| OVI law in Ohio | Not mandatory for every first offense; the court may grant unlimited driving privileges with an ignition interlock device |
| DUI law in Oklahoma | Yes, through IDAP for the revocation period (at least 180 days); at least 180 days for aggravated DUI |
| DUII law in Oregon | Yes, for 1 year after the suspension ends |
| DUI law in Pennsylvania | Not for a first general impairment offense; required after a suspension for a first high-rate, highest-rate or refusal case before full restoration |
| DUI law in Rhode Island | Discretionary for a first offense with BAC under 0.15; mandatory (interlock and/or blood and urine testing) for a first offense at BAC 0.15 or more or with drug impairment |
| DUI law in South Carolina | Yes: 6 months for a first DUI or DUAC conviction (does not apply to a person who took a breath test and had an alcohol concentration of 0.00) |
| DUI law in Tennessee | If you drive during the 1-year revocation, the interlock is required for the ignition interlock usage period (365 consecutive days or the whole revocation, whichever is longer); if you wait out the revocation, the department will not reinstate your license until you show proof of a current interlock installation, and the usage period starts on reinstatement |
| DWI law in Texas | Required as a community supervision condition when BAC was 0.15 or more, on deferred adjudication for DWI (unless waived after an alcohol evaluation), and for drivers under 21; otherwise at the court's discretion. |
| DUI law in Utah | Ordered as a probation condition unless the court finds it unnecessary; mandatory if you were under 21. Interlock restriction lasts 18 months after a first alcohol DUI conviction (2 years if under 21). |
| DUI law in Vermont | Optional: a first offender may choose to drive on an ignition interlock RDL during the suspension and must stay on it for the suspension period before reinstatement |
| DUI law in Virginia | Yes, as a condition of a restricted license: at least 12 consecutive months without alcohol-related violations (for drug-only DUI the court may order it) |
| DUI law in Washington | Yes. The court must order an ignition interlock on every DUI conviction, and DOL restricts you to interlock-equipped vehicles for at least 1 year after a first restriction |
| DUI law in West Virginia | Mandatory for a first revocation at 0.15 or higher (at least 270 days); optional for a standard first offense (at least 125 days) or a first refusal (at least 1 year) |
| OWI law in Wisconsin | only if alcohol concentration was 0.15 or more, or after an improper test refusal |
| DUI law in Wyoming | 6 months, only if the administrative action shows an alcohol concentration of 0.15 or more |
From each state's statutes, DMV and court pages, checked October 2026. Each state's page links its sources.
How Long the Requirement Really Lasts
The number in the statute is a minimum, not a release date. Two rules stretch it.
The clock may not start when you think. In Wisconsin, the interlock lasts at least 1 year after the DMV issues a license, and the clock starts only once a license is issued. In New Hampshire the interlock period starts only after driving privileges are fully restored. In Arizona it starts when you finish screening, education or treatment and are otherwise eligible to reinstate. In Utah it runs from the day you prove installation and reinstate, and is extended by any days the device is removed.
Removal is earned. Many states require a clean stretch at the end:
- Washington: 180 consecutive days with no failed starts at 0.04 or more, missed or failed random tests, missed service or unauthorized removal.
- Minnesota: no breath alcohol of 0.02 or higher in the preceding 90 days, plus completed treatment.
- Oregon: a 90-day no-negative report at the end, or the requirement continues.
- Maryland and Missouri: 3 consecutive violation-free months.
- Kentucky: 90 consecutive violation-free days for a first offense, 120 for later ones.
Violations add time. In Alabama each violation (four or more 0.02 readings in a month, tampering, or missed 30-day service) adds 6 months. In Connecticut each reported violation adds 30 days. In Colorado three failed starts in any 12 consecutive months can add up to 1 year.
Ignition Interlock Costs and Fees
The device cost falls on you. Florida installs it at the offender’s expense on every vehicle you routinely drive (Fla. Stat. § 322.2715), and Connecticut, Idaho, Nevada, Oregon and Michigan all put installation and maintenance on the driver.
PennDOT’s fact sheet puts average lease costs at $900 to $1,300 per year. Kentucky caps provider fees by statute: installation up to $100 or $130, and monthly fees up to $100.
State fees come on top of the device:
| State | Fees set by the state |
|---|---|
| Alabama | $200 court fee and up to $150 restricted license fee |
| Connecticut | $100 DMV interlock administration fee and $175 reinstatement fee |
| District of Columbia | $50 application fee |
| Illinois | Up to $30 a month to the Secretary of State |
| Maine | $50 administrative fee |
| Oklahoma | $50 restricted license fee |
| Virginia | $20 court fee |
| Wyoming | $50 reinstatement fee, the regular license fee and a $100 interlock administrative fee |
Service visits are part of the cost. Colorado requires service every 60 days, Connecticut calibration every 25 to 30 days, and Nevada inspection and calibration at least every 90 days.
Help if You Can’t Afford an Interlock
If cost is the barrier, look for your state’s low-cost or indigent program before you assume you can’t comply. Several states build one into the law:
- Maine: providers must cut costs at least 50% for households at or below 150% of the federal poverty guidelines.
- Vermont: low-income drivers may get a 50 percent device-cost reduction.
- New Hampshire: a fee reduction of up to 75% is available after a hearing.
- Wyoming: people eligible for SNAP may have half the device cost paid by the state.
- District of Columbia: the DMV pays program costs for indigent participants.
- Maryland and West Virginia: fees are waived for indigent participants (in West Virginia, installation and removal fees).
- New Mexico and South Carolina: state funds help drivers who qualify.
- North Carolina: a partial cost waiver is available on a hardship affidavit.
- Texas and Utah: you pay unless the court finds you can’t (Texas) or are indigent (Utah).
Idaho courts may allow use of the court interlock fund on a showing of financial hardship, though financial hardship alone won’t excuse the requirement.
Getting the Device Installed and Licensed
The order matters, and missing a step can cost you time.
- Find out what’s ordered. The court, the licensing agency or both may require an interlock. Arkansas requires a Confirmation of Interlock Requirement form submitted to Driver Control.
- Use an approved provider. New Jersey requires installation in New Jersey by an MVC-licensed installer. Kansas devices must be approved by the Kansas Highway Patrol.
- Install on the right vehicles. Wisconsin requires a device in every vehicle titled or registered to you unless the court exempts it. Florida covers every vehicle you own or lease and routinely drive.
- Get the interlock license. Many states tie the device to a restricted license; Wyoming counts time only once the interlock license is issued. The hardship license guide explains those licenses, and many also require an SR-22 filing.
- Keep every service appointment and keep proof of each one.
Look up your state’s rules on its interlock page, such as New Jersey, Wisconsin, Pennsylvania or Washington, or start from the state-by-state page. If you were just arrested, the first deadline is the license hearing: find it with the DUI deadline calculator. A lawyer licensed in your state, the bar’s referral service or the public defender can tell you whether an interlock election makes sense in your case.
Frequently Asked Questions
Can I Drive My Employer's Car Without an Interlock?
In some states, yes, under strict conditions. Texas exempts an employer-owned vehicle driven for work if the employer is notified and you don't own or control the business. Utah allows it with employer verification if the vehicle isn't for personal use and you don't own the business. Wyoming exempts an employer's vehicle used only for business, and Kentucky has an employer-vehicle exemption.
Does Interlock Time Before Conviction Count?
In some states. New Mexico gives credit for time on an interlock before conviction. Kentucky counts time on an interlock license day for day toward the suspension, and you can apply even before conviction. Indiana credits interlock time under specialized driving privileges or a pretrial order toward the suspension.
What Happens if I Remove the Interlock Early?
It usually costs you the license and restarts or extends the requirement. In Arizona, removing the device early suspends your license and restarts the requirement. In Washington, driving without the device or tampering adds 180 days. In Maine, driving without it or tampering is a Class E crime with at least 7 days in jail and a $500 fine.
Do I Need an Interlock on a Motorcycle?
Some states exclude them. Wisconsin doesn't require the device on motorcycles, mopeds or autocycles, and South Carolina's requirement covers any vehicle you drive except a moped or motorcycle. In other states, a vehicle without a device may simply be off-limits to you.
Is an Interlock Required for a Drug-Only DUI?
Often not in the same way, since the device tests breath alcohol. Rhode Island lets a court use blood and urine testing instead for drug-only cases. Virginia lets the court decide whether to order an interlock for a drug-only DUI. Check your state page for how it handles drug-only cases.
Does an Interlock Affect My Commercial License?
Usually you can't drive a commercial vehicle on an interlock-restricted license. Nebraska's permit isn't valid for commercial vehicles, Wyoming doesn't issue interlock licenses to CDL holders, and DC requires CDL holders to downgrade. See DUI with a CDL.
More on License and SR-22
- Hardship LicenseRestricted and occupational licenses, by state
- SR-22 InsuranceWhat an SR-22 (or FR-44) filing is and how long states require it
- DUI vs DWI vs OWIWhat each term means and which states use which
- What OWI MeansOperating while intoxicated, and the states that use the term
- Blood Alcohol LimitsThe 0.08 limit, commercial and under-21 limits, and enhanced-BAC tiers
- Implied ConsentWhat refusing a breath or blood test costs you, state by state
This guide explains DUI law in plain language from official sources. It isn't legal advice; laws differ by state and change, and a lawyer licensed in your state can advise on your case.