Interlock laws and costs in all 51 US jurisdictions
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The device is the same federally specified box in every state. Everything around it is not: how long you keep it, what breaks the term, who decides that, and what you may be charged are set separately by 51 jurisdictions, and they disagree with each other more than most people expect.
This page is the whole picture on one screen. Every figure comes from the state’s own regulation, fee schedule or agency page, with the date we checked it; each state links through to its page, where the source document is cited line by line.
| Jurisdiction | First-offense term | Locks out at | Install | Monthly | Removal | Program run by |
|---|---|---|---|---|---|---|
| Alabama | 90 days below 0.15% BAC (which cancels the 90-day suspension); 1 year at 0.15% or above, on a refusal, with a child under 14 in the car, or where someone was injured | set by the device standard | — | — | — | Alabama Law Enforcement Agency, on the convicting court order |
| Alaska | Set by the court at sentencing: it must order a device, the length depends on how many previous DUI or refusal convictions you have, and the court may exceed the statutory minimum at its discretion | set by the device standard | — | — | — | Alaska DMV, Driver Services, on the court judgment |
| Arizona | At least 12 months on a standard first conviction; longer at higher readings — 12 months for Extreme DUI at 0.15%, 18 months for Super Extreme at 0.20% (A.R.S. 28-1382) | 0.020% | Not published | Not published | Not published | Arizona MVD (Department of Transportation) |
| Arkansas | A period equal to the driving license suspension, with the restriction lasting until that period is complete | set by the device standard | — | — | — | Arkansas Office of Driver Services (Department of Finance and Administration) |
| California | None for a first non-injury offense; 1 year if it caused injury; with one prior, 1 year (2 with injury); with two, 2 years (3 with injury); with three or more, 3 years | set by the device standard | by income | by income | by income | California DMV, on the court abstract of conviction |
| Colorado | 9 months for a first offense below 0.149% (running alongside the revocation); 2 years at 0.15% or higher, and 2 years automatically for refusing the test | set by the device standard | — | — | — | Colorado DMV (Department of Revenue) |
| Connecticut | Required to reinstate after any alcohol-related suspension; the clock starts on the day your license is restored, not the day the device is fitted | set by the device standard | — | — | — | Connecticut DMV |
| Delaware | Set by the program you enter: Delaware runs a First Offense Election diversion with the device and a separate voluntary program, and the license is not issued until you meet the minimum qualifications | set by the device standard | $100 | $75 | No charge | Delaware Division of Motor Vehicles, IID Unit |
| District of Columbia | Set by the program enrollment period, which the DMV extends if you break the program rules or pick up another driving violation | set by the device standard | — | — | — | DC DMV |
| Florida | Court discretion on a plain first conviction; at least 6 months at 0.15% or with a minor in the car. Second conviction 1 year (2 years at 0.15%), third 2 years, fourth or more 5 years | set by the device standard | — | — | — | Florida Department of Highway Safety and Motor Vehicles |
| Georgia | Set by the permit rules: a second DUI within five years requires the interlock permit under O.C.G.A. 40-5-63(a)(2), and anyone excused from the device on financial hardship grounds gets no limited permit until the required period is served | set by the device standard | $75 | $75 | $75 | Georgia Department of Driver Services, with court authorization for repeat offenses |
| Hawaii | Ordered for the revocation period; Hawaii DOT states the device must be fitted on any vehicle you operate and maintained at your own expense | set by the device standard | — | — | — | Hawaii Department of Transportation and the district courts |
| Idaho | Tied to the administrative license suspension; ITD collects the reinstatement fee and issues the restricted driving permit that the device makes possible | set by the device standard | — | — | — | Idaho Transportation Department, with the court setting the sentence |
| Illinois | For the length of the statutory summary suspension; the Secretary of State downloads the device data every 30 to 60 days and asks you to explain any violation it finds | 0.025% | $85 | $110 | $150 | Illinois Secretary of State, BAIID Division |
| Indiana | Set by the court as a condition of specialized driving privileges; the installation period is credited against the suspension | set by the device standard | — | — | — | The petitioning court, with the record held by Indiana BMV |
| Iowa | For the length of the temporary restricted license on a first OWI; with two or more offenses, at least 365 days from the date you receive the license or the length of it, whichever ends later | set by the device standard | — | — | — | Iowa DOT, Motor Vehicle Division |
| Kansas | Below 0.15% BAC a first occurrence is a 30-day suspension followed by six months or a year restricted to the device; at 0.15% or above it is a year of suspension followed by a year on the device | set by the device standard | Not published | Not published | Not published | Kansas Department of Revenue, Division of Vehicles |
| Kentucky | Suspension drops from 6 months to 4 if you clear 90 consecutive violation-free days on the device; second offense 18 months down to 12 (120 clean days), third 36 to 18, fourth 60 to 30 | set by the device standard | — | — | — | Kentucky Transportation Cabinet, which runs the interlock program directly |
| Louisiana | Matched to the suspension the device buys you out of; the OMV handles reinstatement and holds the record of the requirement | set by the device standard | — | — | — | Louisiana Office of Motor Vehicles (Department of Public Safety and Corrections) |
| Maine | Reinstatement after 30 days of a 150-day suspension, with the device for the remaining term; a second offense reinstates after 9 months of three years, a third after 3 years of six | set by the device standard | — | — | — | Maine Bureau of Motor Vehicles (Secretary of State) |
| Maryland | Set on referral by the MVA, a court or an administrative law judge; a repeat offender within five years faces a year of suspension or a year in the program, then a further restricted year | 0.025% | $70–$150 | $70–$100 | Not published | Maryland Motor Vehicle Administration |
| Massachusetts | For the whole hardship license period; multiple-OUI offenders keep the device a further two years after full reinstatement. Since 1 July 2021 certain first offenders seeking a hardship license need one too | set by the device standard | — | — | — | Massachusetts RMV, Driver Control Unit |
| Michigan | Set through the Secretary of State hearing process as a condition of the restricted license, not fixed as a single term by MCL 257.319 | set by the device standard | — | — | — | Michigan Secretary of State, through its hearing officers |
| Minnesota | Optional for a first offense; mandatory on a second or later alcohol or drug offense within 20 years (10 years for incidents before 1 July 2025). Drivers canceled as inimical to public safety serve 3–6 years | 0.02% | — | — | — | Minnesota Department of Public Safety, Driver and Vehicle Services |
| Mississippi | Set by the court order for an interlock-restricted license, which is what avoids the administrative suspension in the first place | set by the device standard | Not published | Not published | Not published | Mississippi Department of Public Safety, on the court order |
| Missouri | 90 days on an immediate restricted privilege with the device (request within 15 days of the notice), against a 30-day suspension plus 60-day restricted privilege without it | set by the device standard | — | — | — | Missouri Department of Revenue, Driver License Bureau |
| Montana | For the probationary period set by the court. The underlying suspension is 6 months for a first DUI conviction or a first refusal, and a year for a second or subsequent within 10 years | set by the device standard | — | — | — | The sentencing court, with records held by the Montana Motor Vehicle Division |
| Nebraska | Set by the revocation you waive the hearing on; you must serve any required wait period first, and the permit needs a certificate of installation for every vehicle you will drive | set by the device standard | — | — | — | Nebraska DMV, Financial Responsibility Division |
| Nevada | 185 days for a first conviction below 0.18% BAC; 12 to 36 months at 0.18% or above; one year for a second conviction within 7 years, three years for a felony | set by the device standard | — | — | — | The sentencing court, with the record held by Nevada DMV and Department of Public Safety |
| New Hampshire | Ordered by a New Hampshire court or by the Commissioner of Safety under RSA 265-A:36; you may only drive vehicles fitted with a NH-approved device | set by the device standard | — | — | — | NH Division of Motor Vehicles, or the court |
| New Jersey | 3 months at 0.08–0.10% BAC; 7–12 months at 0.10–0.15%; 12–15 months at 0.15% or higher | set by the device standard | — | — | — | New Jersey Motor Vehicle Commission, on the sentencing court order |
| New Mexico | Required after every DWI conviction, first offense included; the MVD states there is no route around it | set by the device standard | $0–$150 | $60–$80 | Not published | New Mexico Motor Vehicle Division |
| New York | Normally at least 12 months on a DWI sentence, and required of anyone sentenced since 15 August 2010; you have 10 days after sentencing to fit it | 0.025% | $200 | $100 | No charge | The sentencing court and probation, with the restriction recorded by NY DMV |
| North Carolina | 1 year from restoration if the revocation was a year; 3 years if it was four; 7 years after a permanent revocation | 0.02% | — | — | — | North Carolina Division of Motor Vehicles |
| North Dakota | A first offense carries a 91-day suspension below 0.18% BAC, or 180 days at 0.18% and above; the 360 days of 24/7 Sobriety Program participation start with a second offense within seven years | set by the device standard | — | — | — | North Dakota DOT and the Attorney General 24/7 Sobriety Program, through local law enforcement |
| Ohio | For the period of the license suspension, which the court may cut by up to half when it grants unlimited driving privileges with a certified device (ORC 4510.022(C)(2)(b)) | set by the device standard | — | — | — | The sentencing court, with the restricted license issued by Ohio BMV |
| Oklahoma | 180 active interlock days for a first revocation, 365 for a second, 730 for a third or later — and the last 90 days of each must be violation-free | set by the device standard | $150–$350 | $99.99–$114.99 | $89–$150 | Board of Tests for Alcohol and Drug Influence, with driving privileges issued by Service Oklahoma |
| Oregon | Set by ORS 813.602 for the underlying suspension; the hardship permit runs alongside it and requires the device on any vehicle you drive | set by the device standard | — | — | — | Oregon DMV (Department of Transportation), with the court on diversion cases |
| Pennsylvania | None for a first general-impairment offense; required at high BAC, on a refusal, or on a repeat, with the Ignition Interlock Limited License as the route back to driving | set by the device standard | — | — | — | PennDOT, Bureau of Driver Licensing |
| Rhode Island | Granted by the sentencing court under RIGL 31-27-2.8(b)(7) together with a hardship license; you must report the order to the DMV Adjudication Office at once so the restriction is added | set by the device standard | — | — | — | The sentencing court or traffic tribunal, with the restriction recorded by RI DMV |
| South Carolina | Set by the offense under the All Offender Law; drivers who decline to enroll simply stay suspended indefinitely rather than serving a fixed term | set by the device standard | — | — | — | SC Department of Probation, Parole and Pardon Services, with SCDMV holding the record |
| South Dakota | Set by the court or supervising agency; the interlock is ordered case by case rather than by a fixed statutory term | set by the device standard | — | — | — | The court or supervising agency, with the 24/7 program run by the Attorney General |
| Tennessee | Set by the court order for a restricted license (form ORDL signed by the judge), which the provider uses to calculate your time in the program | set by the device standard | $225 | $125 | $75 | The sentencing court, with the restricted license issued by TN Department of Safety |
| Texas | For the duration of the suspension, unless the court finds good cause to remove the device early | set by the device standard | — | — | — | Texas Department of Public Safety, on the court order |
| Utah | 18 months if you were 21 or older at arrest, 3 years if under 21; the Division states that subsequent offenses carry longer restriction periods | set by the device standard | — | — | — | Utah Driver License Division (Department of Public Safety) |
| Vermont | For the balance of the suspension as a conditional reinstatement; the license renews annually until you are eligible for an unrestricted one | 0.02% | — | — | — | Vermont DMV, RDL Unit |
| Virginia | Not less than 12 consecutive months without an alcohol-related violation of the interlock requirements, and no longer than the period of suspension and restriction | 0.02% | $65 | $95 | No charge | A local Alcohol Safety Action Program (ASAP), overseen by the Commission on VASAP |
| Washington | For the remainder of the suspension, revocation or denial — you may apply at any point, including immediately after arrest | set by the device standard | $250 | $150–$191 | $100 | Washington State Department of Licensing |
| West Virginia | Set by the Test and Lock Program; you must have the device fitted within six months of applying, and complete the program before full privileges are restored | 0.025% | — | — | — | West Virginia DMV |
| Wisconsin | Minimum 12 months, counted from the day a license is issued — ordered only at 0.15% BAC or higher, or on refusal | 0.02% | — | — | — | The convicting court, with the order enforced by Wisconsin DOT / DMV |
| Wyoming | Required on a first conviction only at 0.15% BAC or above, and on any second or subsequent conviction whatever the reading; the clock does not start until the interlock license is issued, however long the device has been fitted | set by the device standard | — | — | — | Wyoming Department of Transportation, Driver Services |
Download the table: terms, thresholds and agencies (CSV) · published fees and caps (CSV). Free to reuse with attribution.
What the table shows once you read down the columns
The first-offense column is the one people look at, and it is the one that misleads most. It is a floor. Almost every program also requires a clean window before the device comes out, and events inside that window push the end date further away than the difference between any two states’ statutory terms. A short term with a hair-trigger violation rule holds you longer than a long term with a forgiving one.
The threshold column is mostly not a number, and that is the honest answer rather than a gap in our data: 41 jurisdictions do not fix the level in statute at all. It is set by the certifying agency in the device standard, in practice between 0.02 and 0.025 percent — far below the 0.08 percent driving limit, which is the point. The device is not testing whether you are impaired. It is testing whether you drank.
The three money columns are empty for most of the country, and that emptiness is the finding. Only 14 jurisdictions publish a figure or cap what a provider may charge. Everywhere else the price is whatever the quote says, which is why the same device costs differently in two neighbouring cities. How the full-term cost adds up →
The last column decides more than it looks. Whoever runs the program is who reads the device report and decides whether an event was a violation, and who you apply to for early removal, a medical exemption or help with the cost. In some states that is the licensing agency, in others the state police lab or the sentencing court, and the route is different in each. What counts as a violation →
How to read your own row
Start with the agency, because everything else routes through it. Then check whether your state appears in the fee columns: if it does, the published number is binding on the provider and any quote above it is wrong. If it does not, get two quotes, because nothing constrains them. Then read the term as a minimum and look up what your state counts as an event, since that is what decides whether the minimum is what you serve.
Where money is the obstacle, the answer is usually in the state’s own rules rather than with the provider — several states waive, halve or reimburse the cost for drivers below an income line. What states do for drivers who cannot pay →
Questions this table answers
Which states require an interlock for a first offense?
Most of them, and the trigger differs more than the requirement. Some states attach the device to any conviction, some only above a set reading, and some leave it to the judge. The column that matters in the table below is the first-offense term: where it carries a number, the device follows the conviction rather than the judge’s mood.
Which state has the strictest interlock laws?
Strictness has two separate axes and no state leads on both. One is how long the device stays: the first-offense terms in the table run from a few months to well over a year for the same conduct. The other is what breaks the term — several states restart the clock or add time for events that other states ignore entirely, and a state with a short nominal term and a hair-trigger violation rule can hold you longer than a state with a long one.
How long do you have to have an interlock?
The number in your order is a floor, not a date. Almost every program requires a clean window before it lets the device come out — 180 days in Washington, the last 30 in New Jersey, three months in Maryland — and events inside that window push the end date out. The table gives the statutory first-offense term for each jurisdiction; what you actually serve is that term plus whatever the monitoring reports add.
What blood alcohol level does an interlock lock out at?
Far below any driving limit. Where a state prints a number it is typically 0.02 to 0.025 percent, against a 0.08 percent driving limit. Forty-one of the 51 jurisdictions do not print a number in the statute at all: the level is set by the certifying agency in the device standard, which is why the threshold column below says who sets it rather than inventing a figure.
How much does an interlock cost by state?
Nationally about $70–$90 to fit and around $70 a month (NHTSA). 14 jurisdictions publish their own figures or cap what a provider may charge, and inside those the published number beats any phone quote. Everywhere else the quote is the price.
Who runs the interlock program in each state?
Not one kind of body. In some states it is the licensing agency, in others the public safety department, the state police lab, or the sentencing court. It matters because that is who decides whether a recorded event counts as a violation, and who you apply to for anything — early removal, a medical exemption, help with the cost.
Can the interlock requirement be waived?
Rarely waived, sometimes shortened, and often subsidised. Several states cut or cover the cost for drivers below an income line. A few allow the term to be reduced for a clean record or substituted with continuous alcohol monitoring. What almost no state does is remove the requirement because the device is inconvenient or because you do not own a car.
Where does this data come from?
Each row is taken from the state’s own regulation, fee schedule or agency page, with the check date recorded alongside it. Nothing here is copied from a vendor. The full table is downloadable as CSV below, and every state links to its own page where the source document is cited line by line.