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Last updated: January 2, 2025
What to Know About Ignition Interlocks
A state-by-state breakdown of ignition interlock laws
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Table of Contents
- What Is an Ignition Interlock?
- What Are the State Laws Regarding Ignition Interlocks?
- Car Breathalyzer vs. Ignition Interlock Device vs. Breath Alcohol Ignition Interlock Device
- Can My License Be Restored After a DUI Conviction?
- What if Other People Drive My Car That Has an Interlock?
- What Happens if I Buy a New Car or Remove the Interlock?
- Recap
- FAQs
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Driving under the influence of alcohol or drugs can result in loss of driving privileges. Before restoring driving privileges, local authorities often require individuals convicted of DUI to install an ignition interlock in their vehicle. The point of the interlock is to discourage alcohol-impaired driving by preventing drivers with a high BAC (blood alcohol content) from starting their vehicles. Here’s what you need to know about using one.
Editor’s note: We have updated this page with the latest laws, data, and requirements regarding ignition interlocks.
What Is an Ignition Interlock?
An ignition interlock (often simply called an interlock) is a small breathalyzer device for your car.
Before starting the car, the driver must breathe into a mouthpiece on the interlock. The interlock measures the amount of alcohol in the driver’s breath and, if it’s too high, prevents the engine from starting. Drivers with DUIs are often required to install an interlock in their car, requiring a blow pattern before the car will start.
How Does an Ignition Interlock Work?
Ignition interlocks come with a preset threshold for blood alcohol concentration (BAC). If the interlock registers a BAC over that threshold when the driver breathes into the mouthpiece, the vehicle will not start. If the driver’s BAC is below the preset limit, the vehicle will start. Typically, an interlock can detect any alcohol the driver has consumed within the last 12 to 24 hours.
FYI
The exact BAC limit that will prevent you from starting your vehicle varies by state, but is typically around 0.02 percent. See the table below for more details on the interlock BAC limit in your state.
The method required for blowing into the mouthpiece differs depending on the device. The following are most common.
- Blow-inhale-blow: The user blows into the mouthpiece for a few seconds, inhales, and then blows into the mouthpiece again.
- Straight blow: The user simply blows into the mouthpiece with force.
- Blow and hum: The user blows into the device for several seconds while humming at the same time. The device uses the humming to verify that a person is blowing into the mouthpiece.
Interlocks require service and calibration at regular intervals, typically every 30, 60, or 90 days, depending on the state. An authorized service center can perform the required maintenance. In many cases, at the time of calibration, the interlock sends a log of results to local authorities for review.
Some interlocks come equipped with extra features, like a camera or real-time reporting. The required features vary by state.
Often, an interlock requires random retests after you start your vehicle. You should not complete a retest while driving; instead, pull over when your device alerts you. An interlock will never stop your car while you are driving.
The goal of interlocks is to decrease alcohol-related crashes and fatalities and to reduce DUI re-arrest rates. According to the NHTSA, states that require interlocks experience 26 percent fewer fatal alcohol related crashes than states that do not. They also found states that require interlocks only for repeat offenders experience 20 percent fewer alcohol related crashes.1
Where Can I Get an Interlock?
You will need to go to an authorized service center to get an interlock device. A number of companies lease them, such as LifeSafer, SmartStart, and Intoxalock. Interlock companies allow you to search their websites for authorized service center locations near you. Choose an interlock provider based on convenience, price, and required features.
How Much Do Interlocks Cost?
An interlock typically costs $60 to $90 per month, depending on the type of vehicle, state, interlock term length, and any additional required features (like a camera or GPS). You may also have to pay a one-time installation fee of $75 to $150. Providers lease ignition interlocks, rather than sell them outright, because you’ll need one only for the duration the court requires.
FYI
Expect your car insurance rates to increase if you receive a DUI. Learn more about how DUIs affect auto insurance rates.
How Do I Install an Interlock?
A state-certified provider must install the interlock for you. Many local auto service shops offer interlock services. The company from which you lease the interlock will help you locate a service provider.
When the provider installs the interlock, they will show you how to use it properly. Anyone who drives your car regularly should also receive training on how to use the interlock. Improperly using an interlock can result in test fails, which show up on your driving record.
What Is a DUI Interlock Program?
A DUI interlock program is a state-mandated plan to get drivers back on the road safely after DUI convictions. Programs vary by state but usually contain the same general elements:
- You go to an authorized service provider and pay to have the interlock installed.
- You bring your vehicle back to the provider for regular calibration.
- The device reports your results to monitoring agencies, which check your compliance.
- Sometimes you need to obtain a special drivers license. For example, in Delaware, if you are a first-time offender, you can often apply for a conditional license after completing a state-approved education or treatment program.
- Depending on your state, you may need to complete extra steps. For example, some states require you to complete an alcohol education course, undergo counseling or a psychological evaluation, pay fees, or retake your driver’s tests.
- After you complete the program, bring your vehicle to the service center so that a technician can remove the device.
2
FYI
In addition to installing an interlock device, a DUI interlock program may require you to undergo counseling, pay fees, and retake your driver’s tests.
What Are the State Laws Regarding Ignition Interlocks?
In all states, the maximum legal BAC while driving is 0.08.3 However, state laws differ around driving privileges after a DUI and the circumstances under which you need to install an interlock.
After a DUI conviction, the Department of Motor Vehicles (DMV) will usually suspend your license. In some states, you can drive during the suspension period if you install an interlock. In other states, you cannot drive during the suspension period; instead, you need to wait for the DMV to reinstate your license, which is often conditional on installing an interlock.
Check out the chart below for more details on interlock laws by state.4
| State | Time DUI stays record | Increased BAC threshold | Increased BAC penalty | Administrative license suspension on first offense5 | Limited driving privileges during suspension | When are ignition interlocks mandatory? | Term used to describe interlock | Time required to use interlock |
|---|---|---|---|---|---|---|---|---|
| Alabama | 5 years | 0.15 | 6 months of additional interlock requirement | 90 days | Must apply for hardship license | Mandatory for high BAC (0.15 and above) and repeat convictions; highly incentivized for first convictions | Ignition interlock device (IID) | First offense, BAC under 0.15: 6 months
First offense, BAC over 0.15: 2 years Second offense: 1 year Third offense: 3 years Fourth and subsequent offenses: 4 years |
| Alaska | Lifetime | None | None | 90 days | After 30 days | Mandatory for all convictions | IID | First conviction: 6 months
Second conviction: 12 months Third conviction: Variable at the court’s discretion |
| Arizona | Lifetime | 0.15 and 0.2 | 0.15 or above: 6 months of additional interlock requirement, minimum 9 days jail time
0.2 or above: Minimum 14 days jail time | 90 days | After 30 days | Mandatory for all convictions | Certified IID | Second or third offense, or offense in which you are driving on a suspended or revoked license due to a prior DWI offense, or you endanger a child with your drunk driving: 1 year after the license suspension/revocation ends or the date of the conviction, whichever is later |
| Arkansas | 5 years | None | None | 6 months | Yes | Mandatory for all convictions | IID |
First offense: 6 months
Second offense: 1 year Third offense: 2.5 years Fourth offense: Lifetime interlock required |
| California | 10 years | 0.15 | “Heightened consideration” (at court’s discretion) | 6 months | After 30 days | Discretionary; mandatory for all convictions in Alameda, Los Angeles, Tulare, and Sacramento counties (pilot project extended) | IID |
First offense: 6 months
Second offense: 1 year Third offense: 2 years |
| Colorado | 10 years | 0.15 | Interlock for 1 year | 9 months | Yes | Mandatory for high BAC (0.15 and above) and repeat convictions; highly incentivized for
first convictions | IID |
First offense, BAC >0.15: 8 months
First offense, BAC <0.15: 2 years Second offense: 2 years |
| Connecticut | 10 years | None | None | 45 days | Yes | Mandatory for those with BAC of 0.8 or higher | IID |
First offense: 1 year
Second offense: 3 years |
| Delaware | Minimum of 5 years | 0.15 and 0.2 | 0.15 to 0.19: 6 months of additional license suspension (18 months total)
0.2 or above: 12 months of additional license suspension (24 months total) | 1 year | No | Mandatory for those with BAC of 0.15 or higher | IID |
First offense: 12-23 months
Second offense: 16-28 months Third offense: 21-33 months Fourth offense: 54 months |
| District of Columbia | 15 years | 0.2, 0.25, and
0.3 | 0.2 to 0.24: Additional 10 days of mandatory jail time
0.25 to 0.29: Additional 15 days of mandatory jail time 0.3 or above: Additional 20 days of mandatory jail time | 6 months | Yes | Mandatory for all convictions | IID | First conviction: 6 months
Second conviction: 1 year Third and subsequent convictions: 2 years Third conviction within 5 years: Lifetime |
| Florida | 75 years | 0.15 and 0.2 | Additional penalties for BAC 0.15 or above while under age 18
First offense: $1,000-$2,000 fine, up to 9 months of jail time, 6-month minimum interlock requirement Second offense: $2,000 to $4,000 fine, up to 12 months jail time, 2-year minimum interlock requirement Third and fourth offenses: $4,000 minimum fine, plus the above penalties | 6 months for DUI, 12 months for refusal | After 30 or 90 days | Mandatory for all high-BAC offenders | IID |
First conviction <0.15 or a minor in the vehicle: 6 months Second conviction: 1 year Third conviction: 2 years |
| Georgia | 5 years | 0.15 | 0.15 BAC on first offense receives same sentence as those convicted of second offense: $1,000-$3,000 fine, 6-12 months of jail time (judge may suspend all but 15 days), 5-year license revocation, 1-year interlock minimum | 1 year | Yes | Mandatory for repeat convictions | IID | First offenders: 4 months if you agreed to take a breath test; 12 months if you refused a breath test.
Second and subsequent offenders: 14 months from the issuance of limiting driving privileges |
| Hawaii | 5 years | None | None | 1 year | After 30 days | Mandatory for all convictions | IID | First offense: 1 year
Second offense: 18 months Third offense: 2 years |
| Idaho | 10 years | 0.2 | First offense: Up to $2,000 fine, 10 days to 1 year of jail time, 1-year license suspension (no restricted license available), interlock required after suspension, alcohol evaluation and treatment, Idaho SR-22 additional insurance requirement
Second offense: Felony offense, up to $5,000 fine, minimum 30 days in county jail, up to 5 years in state penitentiary, 1-5 years of license suspension (no restricted license available), interlock required after suspension, alcohol evaluation and treatment, Idaho SR-22 additional insurance requirement | 3-6 months | After 30 days | Mandatory for all convictions | IID | 1 year following drivers license suspension |
| Illinois | Lifetime | 0.16 | First offense: Minimum $500 fine, 100 hours of community service
Second offense: Minimum $1,250 fine, 2 days of mandatory imprisonment Third offense: Minimum $2,500 fine, 90 days of mandatory imprisonment Fourth and additional offenses: Minimum $5,000 fine | 1 year | After 30 days | Mandatory for all convictions; highly incentivized for first convictions | Breath alcohol IID | Period of statutory license suspension. 5 year interlock requirement for those with 3 convictions. |
| Indiana | Lifetime | 0.15 | First offense: Up to $5,000 fine, up to 1 year of jail time | 30 days – 2 years | Available immediately | Mandatory for repeat convictions | IID or in-car breathalyzer |
At least 60 days after your license has been reinstated. |
| Iowa | 12 years | 0.15 | 48 hours of jail time | 180 days | After 30 days | Mandatory for all convictions | IID | First offense, BAC <0.10: 6 months
Second offense: 1-2 years |
| Kansas | Lifetime | 0.15 | First offense: 1-year license suspension (as opposed to 30 days)
Second offense: 2-year interlock requirement following suspension Third offense: 3-year interlock requirement following suspension Fourth offense: 4-year interlock requirement following suspension | 30 days | Can apply for limited license after 45-90 days | Highly incentivized for all convictions | IID | First offense and BAC over 0.08: 6 months if record is clear, 1 year for prior open container violation and/or 3 or more moving violations
BAC over 0.15 the first time or over 0.08 the second or subsequent times, or refusal of a breath, blood, or urine test: Length dependent on priors |
| Kentucky | 5 years | 0.15 | Increased minimum jail time | 6 months | Yes | Mandatory for all convictions | IID | First offense: 6 months after license revocation
Second offense within 5 years: 1 year Third and subsequent offenses within 5 years: 30 months |
| Louisiana | 10 years | 0.15 and 0.2 | 0.15 and above: Enhanced penalties, at court’s discretion
First offense, 0.2 and above: $750-$1,000 fine, 2-year license suspension (as opposed to 1 year) Second offense, 0.2 and above: 4-year license suspension | 1 year | Vehicle confiscation | Mandatory for BACs 0.2 and above and repeat convictions; highly incentivized for first convictions | IID |
First offense: For the remainder of your suspension
2 DUI offenses and license revoked for 2 years: 2 years 3 offenses: 3 years 4 or more offenses: 4 years |
| Maine | Lifetime | 0.15 | Minimum 48-hour imprisonment | 150 days | Yes | Highly incentivized for all convictions | IID | 2 years as a condition of license reinstatement
2 DUI offenses and license revoked for 2 years: 9 months 3 DUI offenses: 3 years 4 or more offenses: 4 years |
| Maryland | 3 years | 0.15 | Ineligible for modification of a license suspension or issuance of a restrictive license | 90 days | Yes, with interlock | Mandatory for all convictions | IID | 1-3 years
BAC of 0.15 or more: 1 year minimum |
| Massachusetts | 10 years | 0.2 | Mandatory alcohol treatment program | 1 year | Yes | Mandatory for repeat convictions | Ignition interlock device (IID) | First offense, high BAC: 2 years
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: 5 years |
| Michigan | Lifetime | 0.17 | First offense: $200-$700 fine, up to 180 days in jail (as opposed to 90 days), 1-year license suspension (as opposed to 6 months) | 30-180 days | After 45 days | Mandatory for high BAC (0.17) and repeat convictions | Breath alcohol IID | First offense, BAC <0.17: 6 months
Second offense: 1 year With a minor: 3 years |
| Minnesota | Lifetime | 0.16 | Unless maximum bail is imposed, must agree to abstain from alcohol use and submit to daily monitoring of alcohol levels before release from detention | 90 days | After 15 days | Highly incentivized for high BAC (0.16) and repeat convictions | IID
or in-car breathalyzer |
First offense BAC >0.16: 90 days
First offense BAC <0.16: 1 year Second offense: 1 year Third offense: 3 years |
| Mississippi | 5 years | None | None | 120 days | With interlock | Mandatory for all convictions | IID | First offense: 120 days
Second offense: 1 year Third offense: 3 years after jail time |
| Missouri | 10 years | 0.15 and 0.2 | 0.15 to 0.19: 2-day mandatory imprisonment
0.2 and above: 5 days of mandatory imprisonment 0.15 and above: Mandatory drug or alcohol education/rehabilitation program | 90 days | After 0 days with interlock use (restricted)
After 30 days (restricted) | Mandatory for repeat convictions | IID | At least 6 months, regardless of prior offenses |
| Montana | Lifetime | 0.16 | First offense: Up to $1,000 fine, 48 hours to 1 year of imprisonment
Second offense: $2,500 fine, 15 days to 1 year of imprisonment Third offense: $5,000 fine, 40 days to 1 year of imprisonment | 6 months | Yes | Mandatory for repeat convictions | IID | First offense: 6 months
Second offense : 1 year Third offense: 2 years |
| Nebraska | 12 years | 0.15 | First offense: Additional $500 fine, 1-year license revocation (as opposed to 2 to 6 months)
Second offense: Additional fine up to $1,000, license revocation up to 15 years Third offense: Felony charge, additional fine up to $10,000, up to 5 years of imprisonment (as opposed to 1), license revocation of 5-15 years (as opposed to 2-15) Fourth offense: Class III felony charge, additional fine up to $25,000, up to 20 years of imprisonment, possible use of alcohol-monitoring device for minimum 6 months Fifth and subsequent offenses: Class II felony charge, additional fine up to $25,000, up to 50 years of imprisonment | 90 days | After 30 days | Mandatory for all convictions | Breath alcohol IID |
First offense if you fail chemical test: 180 days Subsequent offense after 15 years, if you fail chemical test: 1 year If you fail a chemical test on arrest: 90 days |
| Nevada | 7 years | 0.18 | First and second offenses: 12-36 months of mandatory interlock (as opposed to 3-6 months), alcohol treatment | 180 days | After 45 days | Mandatory for all convictions | IID or breath interlock device |
With <0.18 BAC or higher: 12-36 months With >0.18 BAC: 185 days |
| New Hampshire | 10 years | 0.16 | Class A misdemeanor, 5 days to 1 year of jail time, $750-$2,000 fine, interlock required for first offense | 9 months | No privileges during suspension | Mandatory for all convictions | IID | First offense: 1-2 years if aggravating factors are present (e.g., high BAC)
Second and subsequent offenses: 1-2 years |
| New Jersey | 10 years | 0.15 | Interlock requirement | 3 months | Must apply for hardship license | Mandatory for all convictions | Breath alcohol IID | First offense: 6 months to 1 year
Second and subsequent offenses: 1-3 years |
| New Mexico | 55 years | 0.16 (with mandatory jail time for all offenses) | Aggravated penalty at court’s discretion | 1 year | Immediately, with ignition interlock | Mandatory for all convictions | IID | First offense: 6 months to 1 year
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: Lifetime (reviewed after 5 years) |
| New York | 15 years | 0.18 | First offense: $1,000-$2,500 fine, minimum 1-year license revocation (as opposed to 6 months)
Second and subsequent offenses: Minimum 18-month license revocation | 6 months | Yes | Mandatory for all convictions | IID | Minimum of 1 year |
| North Carolina | 7 years | 0.15 | First offense: 1-year interlock requirement | 1 year | After 10 days | Mandatory for high BAC (0.15 and above) and repeat convictions | IID or in-car breathalyzer | First offense: 1 year
Second offense: 3 years Third offense: 7 years (if license is restored) |
| North Dakota | 7 years | 0.18 | First offense: 180-day license suspension (as opposed to 91 days), minimum $750 fine increase, at least 2 days of imprisonment (court may convert each day into 10 hours of community service)
Second offense: 2-year license suspension Third offense: 3-year license suspension | 91 days | After 30 days | Discretionary | IID | First offense: Not required
Second and subsequent offenses: Encouraged, at court’s discretion |
| Ohio | Lifetime | 0.17 | Up to $1,075 fine, up to 6 months of jail time, license suspension of 6 months to 3 years | 1 year | After 15 days | Mandatory for repeat convictions | IID | First offense: 6-18 months
Second offense: 1-4 years Third offense: 1 year to a lifetime |
| Oklahoma | 10 years | 0.15 | 480 hours of community service, minimum 1 year of supervision and periodic testing
First offense: 18-month interlock requirement | 6 months | Yes | Mandatory for high BAC (0.15 and above) and repeat convictions; highly incentivized for first convictions | IID |
First offense: 18 months or until your driving privileges are reinstated Second offense: 4 years or until your driving privileges are reinstated Third and subsequent offenses: Minimum 5 years or until driving privileges are reinstated |
| Oregon | Lifetime | 0.15 | Minimum $2,000 fine (as opposed to $1,000) | 1 year | After 30 days | Mandatory for all convictions and diversions | IID | 1 to 5 years |
| Pennsylvania | 10 years | 0.1 and 0.16 | First offense, 0.1 to 0.15: $500-$5,000 fine, minimum 48 hours of jail time, 12-month license suspension
First offense, 0.16 and above: $1,000-$5,000 fine, minimum 72 hours of jail time, 12-month license suspension Second offense, 0.1 to 0.15: $750-$5,000 fine, minimum 30 days of jail time, 12-month license suspension Second offense, 0.16 and above: Minimum $1,500 fine, minimum 90 days of jail time, 18-month license suspension Third offense, 0.1 to 0.15: $1,500-$10,000 fine, minimum 90 days of jail time, 18-month license suspension Third offense, 0.16 and above: Minimum $2,500 fine, minimum 1 year of jail time, 18-month license suspension | No | Yes, with programs called Occupational Limited License and Ignition Interlock Limited License | Mandatory for BACs over 0.1 and repeat convictions | IID | First offense: Not required
Second and subsequent offenses: 1 year |
| Rhode Island | 5 years | 0.1 and 0.15 | First offense, 0.1 to 0.14: $100-$400 fine plus $500 highway assessment fine, 3-12 months of license suspension
First offense, 0.15 and above: $500 fine plus $500 highway assessment fine, 3-18 months of license suspension, minimum 20 hours of public community restitution (as opposed to 10 hours) Second offense, 0.15 and above: Minimum $1,000 fine plus $500 highway assessment fine, 6 months to 1 year of jail time, 2-year license suspension Third offense, 0.15 and above: $1,000-$5,000 fine plus $500 highway assessment fine, 3-5 years of jail time, 3-year license suspension | 30 days | Conditional hardship license to commute to work, contingent on interlock | Mandatory for all convictions | IID | First offense: 3 months to a year
Second offense: 6 months to 2 years Third and subsequent offenses: 1 to 4 years |
| South Carolina | 10 years | 0.16 |
First offense: $1,000 fine, 30-90 days of jail time (possibility of community service instead) Second offense: $3,500-$6,500 fine, 90 days to 3 years of jail time Third offense, 0.16 and above: $7,500-$10,000 fine, 6 months to 5 years of jail time Fourth offense, 0.1 to 0.15: 2-6 years of jail time Fourth offense, 0.16 and above: 3-7 years of jail time | 6 months | Yes | Mandatory for all convictions | IID | First offense: 6 months
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: Lifetime, if license is reinstated (may apply to remove interlock restriction after 10 years) |
| South Dakota | 10 years | 0.17 | May be sentenced to a 24/7 continuous sobriety monitoring program and must undergo a court-ordered evaluation by a licensed professional | 30 days | Yes | Discretionary | IID | No mandatory requirements |
| Tennessee | Lifetime | 0.2 | Minimum 7 days of jail time (as opposed to 48 hours) | 1 year | Yes | Mandatory for repeat convictions; highly incentivized for first convictions | IID
or in-car breathalyzer | Up to 1 year upon license reinstatement, regardless of prior offenses |
| Texas | Lifetime | 0.15 | 1 year interlock requirement | 90 days for BAC 0.08 or greater; 180 days for refusal | Yes | Mandatory for repeat convictions and for BAC 0.15 or higher | IID | First offense: 90 days to 1 year
Second offense: 180 days to 2 years Third offense: 1-10 years |
| Utah | 10 years | 0.16 | 1-year interlock requirement (at judge’s discretion for lower BACs) | 120 days | Temporary limited for employment, education, child visitation | Mandatory for repeat convictions; highly incentivized for first convictions | IID | First offense: Not required, may be a condition of probation
Second and subsequent offenses: Required as a condition of probation for a time period determined by the courts (3 years if under age 21) |
| Vermont | Lifetime | 0.16 | Prohibited from driving with a BAC of 0.02 or higher for 3 years after conviction (as opposed to 0.08); during these 3 years, driving with a BAC of 0.02 or higher is a DUI and penalized as such | 90 days | Eligible for interlock-restricted license after 30 days to a year, depending on prior offenses | Highly incentivized for all convictions, mandatory for repeat convictions or BAC 0.15 or higher. | IID | First offense: 6 months
Second offense: 1 year Third offense: 2 years Fourth offense: Lifetime license suspension, no interlock possibility |
| Virginia | 11 years | 0.15 and 0.2 | First offense, 0.15 to 0.2: Additional minimum 5 days of jail time
First offense, 0.2 and above: Additional minimum 10 days of jail time Second offense, 0.15 to 0.2: Additional minimum 10 days of jail time Second offense, 0.2 and above: Additional minimum 20 days of jail time, minimum $500 fine | 1 year | Yes | Mandatory for all convictions | IID | Minimum 6 months upon license reinstatement, regardless of prior offenses |
| Washington | Lifetime | 0.15 | First offense: 1-year license revocation
Second offense: 900-day license revocation Third offense: 4-year license revocation | 90 days | With an ignition interlock driver’s license | Mandatory for all convictions | Breath alcohol IID | First offense: Minimum 1 year
Second offense: Minimum 5 years Third offense: Minimum 10 years |
| West Virginia | 10 years | 0.15 | Mandatory interlock period | 6 months | After 30 days | Mandatory for BACs over 0.15 and repeat convictions | IID | First offense: Minimum 6 months
Second and subsequent offenses: Minimum 2 years |
| Wisconsin | 10 years | 0.17, 0.2, and
0.25 | 0.17 to 0.199: Minimum and maximum fines doubled
0.2 to 0.249: Minimum and maximum fines tripled 0.25 or above: Minimum and maximum fines quadrupled First offense, 0.15 and above: 1-year minimum interlock requirement | 6 months | Yes | Mandatory for high BAC (0.15 and higher) and repeat convictions | IID | First offense: Not required for low-BAC offenders
Second and subsequent offenses: Minimum 1 year, once driving privileges are reinstated |
| Wyoming | 10 years | 0.15 | Interlock required for 6 months after first offense | 90 days | Yes | Mandatory for high BAC (0.15 and higher) and repeat convictions | IID | First offense: Not required for low-BAC offenders
Second offense: 1 year Third offense: 2 years Fourth and subsequent offenses: Lifetime (can appeal for removal after 5 years) |
How Long Do I Need to Use an Interlock?
How long you need to use an interlock depends on the state where you live and whether you have prior DUI convictions. For example, Montana requires individuals to use an interlock for six months after their first DUI conviction, one year after their second, and two years after their third.
In some cases, your BAC at the time of DUI will affect the length of time you need to use an interlock. For example, in North Carolina, after your first DUI conviction, you are required to have an interlock for a year if your BAC was 0.15 or higher.
In addition to using an interlock, you may have to pay other fines and penalties, depending on the state.
Car Breathalyzer vs. Ignition Interlock Device vs. Breath Alcohol Ignition Interlock Device
Car breathalyzer, ignition interlock device (IID), and breath alcohol ignition interlock device (BAIID) are all terms for the same device. The name may vary by state. For example, Illinois and Michigan use the term “breath alcohol ignition interlock device.” Ultimately, they all describe the device used to prevent individuals from driving under the influence.
Can My License Be Restored After a DUI Conviction?
In general, after a DUI conviction, the DMV will restore your driving privileges if you fulfill the conditions that the court ordered. These conditions often include installing an interlock on your vehicle. Some states incentivize the use of interlocks but do not require them.
In addition, before the DMV will restore your driving privileges, you often need to pay a fee. The fee can be expensive and usually increases with each offense. For example, in Illinois, there is a license reinstatement fee of $500.
In states like Arizona and Delaware, you need to complete an alcohol education program. You may need to retake your driver’s license tests, such as the eye screening, written test, and road test.
In some cases, a DUI conviction requires you to serve jail time. For example, in North Carolina, DUI offenders must serve a minimum of 24 hours in jail. Jail time varies depending on state, the circumstances of the DUI, and whether you have prior DUI convictions.
Finally, a DUI conviction and license suspension will affect your car insurance. On average, insurance premiums increase by 80 percent after DUI convictions, and a DUI will likely impact your premiums for at least three years. In some cases, your insurance provider may even drop you as a customer.6
What if Other People Drive My Car That Has an Interlock?
Others are allowed to drive your interlock-equipped car. Before they start the engine, they will need to blow into the mouthpiece, just as you would. There is no way to disable an interlock. Anyone borrowing your car should receive training on how to use the mouthpiece properly and avoid test fails.
Keep in mind that you are responsible for any test fails that show up on your record, so it’s vital that anyone who borrows your car is sober.
In most cases, you must install an interlock on every vehicle you own. If you own multiple vehicles and a family member exclusively drives one of them, you may be able to apply for a waiver. Your state’s DMV will consider waivers on a case-by-case basis and take into account whether installing extra interlocks will cause your family financial hardship.
What Happens if I Buy a New Car or Remove the Interlock?
If you buy a new car, you must install an interlock on the new vehicle. If you don’t, in most cases the DMV will cancel your driver’s license.
Removing or tampering with the interlock will result in fines and an extension of the interlock term. This includes removing the interlock when your term is up. A certified provider should always remove the interlock for you.
IMPORTANT TO KNOW
When your interlock term is up, do not attempt to remove the device yourself. A certified provider should remove it; attempting to remove it yourself will result in fines and an extension of the interlock term.
Can I Rent a Car With an Interlock?
You cannot rent a car if you have an interlock-restricted license. Rental car companies do not have interlock-equipped vehicles and will not rent to individuals with restricted licenses.
Recap
A DUI conviction will often result in a suspended license, which can make it difficult to find auto insurance. Not only will premiums increase, but many auto insurance providers consider individuals with DUIs too risky and refuse to insure them at all. But there are still many insurers who offer affordable DUI insurance.
FAQs
How much does an ignition interlock device cost?
According to interlock provider Intoxalock, ignition interlock devices typically cost $60 to $90 per month, depending on your vehicle type, state, required interlock term, and any additional required features (like a camera or GPS). You may pay a one-time installation fee of $75 to $100. Companies that provide interlocks lease the devices rather than sell them outright.
How long do you have to have an interlock device?
How long you need to have an interlock device on your vehicle depends on your state and whether you have prior DUI convictions. In some states, your BAC at the time of the DUI arrest also impacts the length of your interlock term. Usually, interlock terms start at six months. If you have prior DUI convictions, the state may require you have the device for two years or longer.
The chart below lists the minimum interlock length requirements by state.
| State | Length of time required to use interlock |
|---|---|
| Alabama | First offense, BAC under 0.15: 6 months
First offense, BAC over 0.15: 2 years Second offense: 2 year Third offense: 3 years Fourth and subsequent offenses: 4 years |
| Alaska | First conviction: 6 months
Second conviction: 12 months Third conviction: Variable, at the court’s discretion |
| Arizona | Second or third offense, or offense in which you are driving on a suspended or revoked license due to a prior DWI offense, or endanger a child with your drunk driving: 1 year after license suspension/revocation ends or the date of conviction, whichever is later |
| Arkansas |
First offense: 6 months
Second offense: 1 year Third offense: 2.5 years Fourth offense: Lifetime interlock required |
| California |
First offense: 6 months
Second offense: 1 year Third offense: 2 years |
| Colorado |
First offense, BAC >0.15: 8 months
First offense, BAC <0.15: 2 years Second offense: 2 years |
| Connecticut | First offense: 1 year
Second offense: 3 years |
| Delaware | First offense: 12-23 months
Second offense: 16-28 months Third offense: 21-33 months Fourth offense: 54 months |
| District of Columbia | First conviction: 6 months
Second conviction: 1 year Third and subsequent convictions: 2 years Third conviction within 5 years: Indefinite |
| Florida |
First conviction <0.15 or a minor in the vehicle: 6 months
Second conviction: 1 year Third conviction: 2 years |
| Georgia | First offenders: 4 months if you agreed to take a breath test; 12 months if you refused a breath test.
Second and subsequent offenders: 14 months from when you are issued limiting driving privileges |
| Hawaii | First offense: 1 year
Second offense: 18 months Third offense: 2 years |
| Idaho | 1 year following drivers license suspension |
| Illinois | Period of statutory license suspension. 5 year interlock requirement for those with 3 convictions. |
| Indiana | At least 60 days after your license has been reinstated. |
| Iowa |
First offense, BAC <0.10: 6 months
Second offense: 1-2 years |
| Kansas | First offense and BAC over 0.08: 6 months if record is clear, or 1 year for prior open container violation and/or 3 or more moving violations
BAC over 0.15 the first time or over 0.08 the second or subsequent times, or refusal of a breath, blood, or urine test: Dependent on priors |
| Kentucky | First offense: 6 months after license revocation
Second offense within 5 years: 1 year Third and subsequent offenses within 5 years: 30 months |
| Louisiana | Not specified |
| Maine | First offense: For the remainder of your suspension
2 DUI offenses and license revoked for 2 years: 2 years 3 offenses: 3 years 4 or more offenses: 4 years |
| Maryland | 1-3 years
BAC of 0.15 or more: 1 year minimum |
| Massachusetts | First offense, high BAC: 2 years
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: 5 years |
| Michigan |
First offense, BAC <0.17: 6 months
Second offense: 1 year With a minor: 3 years |
| Minnesota |
First offense BAC >0.16: 90 days
First offense BAC <0.16: 1 year Second offense: 1 year Third offense: 3 years |
| Mississippi | First offense: 120 days
Second and subsequent offenses: 1 year Third offense: 3 years after jail time |
| Missouri | At least 6 months, regardless of prior offenses |
| Montana | First offense: 6 months
Second offense: 1 year Third offense: 2 years |
| Nebraska | First offense if you fail chemical test: 180 days
Subsequent offense after 15 years, if you fail chemical test: 1 year If you refuse a chemical test on arrest: 90 days |
| Nevada |
With <0.18 BAC or higher: 12-36 months
With >0.18 BAC: 185 days |
| New Hampshire | First offense: 1-2 years if aggravating factors are present (e.g., high BAC)
Second and subsequent offense: 1-2 years |
| New Jersey | First offense: 6 months to 1 year
Second and subsequent offenses: 3 years |
| New Mexico | First offense: 6 months to 1 year
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: Lifetime (reviewed after 5 years) |
| New York | At least 1 year |
| North Carolina | First offense: 1 year
Second offense: 3 years Third offense: 7 years (if license is restored) |
| North Dakota | First offense: Not required
Second and subsequent offenses: Encouraged, at court’s discretion |
| Ohio |
First offense: 6-18 months
Second offense: 1-4 years Third offense: 1 year to a lifetime |
| Oklahoma | First offense: 18 months or until your driving privileges are reinstated
Second offense: Minimum 4 years or until driving privileges are reinstated Third and subsequent offenses: Minimum 5 years or until driving privileges are reinstated |
| Oregon | 1 to 5 years |
| Pennsylvania | First offense: Not required
Second and subsequent offenses: 1 year |
| Rhode Island | First offense: 3 months to a year
Second offense: 6 months to 2 years Third and subsequent offenses:1 to 4 years |
| South Carolina | First offense: 6 months
Second offense: 2 years Third offense: 3 years Fourth and subsequent offenses: Lifetime, if license is reinstated (may apply to remove interlock restriction after 10 years) |
| South Dakota | No mandatory requirements |
| Tennessee | Up to 1 year upon license reinstatement, regardless of prior offenses |
| Texas | First offense: 90 days to 1 year
Second offense: 180 days to 2 years Third offense: 1-10 years |
| Utah | First offense: 18 months
Second offense: 3 years |
| Vermont | First offense: 6 months
Second offense: 1 year Third offense: 2 years Fourth offense: Lifetime license suspension, no interlock possibility |
| Virginia | Minimum 6 months upon license reinstatement, regardless of prior offenses |
| Washington | First offense: Minimum 1 year
Second offense: Minimum 5 years Third offense: Minimum 10 years |
| West Virginia | First offense: Minimum 6 months
Second and subsequent offenses: Minimum 2 years |
| Wisconsin | First offense: Not required for low-BAC offenders
Second and subsequent offenses: Minimum 1 year, once driving privileges are reinstated |
| Wyoming | First offense: Not required for low-BAC offenders
Second offense: 1 year Third offense: 2 years Fourth and subsequent offenses: Lifetime (can appeal for removal after 5 years) |
Are there different laws around ignition interlocks for high blood alcohol content (BAC) convictions?
Some states apply additional penalties for individuals convicted of driving with a high BAC. For example, some states require an interlock for first-time offenders only if their BACs were over a certain limit. States may apply other penalties, like additional fines, jail time, or license suspension conditions.
The chart below details state laws around increased BAC convictions.
| State | Limit to be considered increased BAC | Increased BAC penalty |
|---|---|---|
| Alabama | 0.15 | 6-month additional interlock requirement |
| Alaska | None | No increased penalties |
| Arizona | 0.15 and 0.2 | 0.15 or above: 6-month additional interlock requirement, minimum 9 days of jail time
0.2 or above: Minimum 14 days of jail time |
| Arkansas | None | None |
| California | 0.15 | “Heightened consideration to applying [an interlock] sanction to a first-offense violator with BAC of 0.15% or more” |
| Colorado | 0.15 | Interlock for 1 year |
| Connecticut | None | None |
| Delaware | 0.15 and 0.2 | 0.15 to 0.19: 6-month additional license suspension (18 months total)
0.2 or above: 12-month additional license suspension (24 months total) |
| District of Columbia | 0.2, 0.25, and
0.3 |
0.2 to 0.24: Additional 10 days of mandatory jail time
0.25 to 0.29: Additional 15 days of mandatory jail time 0.3 and above: Additional 20 days of mandatory jail time |
| Florida | 0.15 and 0.2 | Additional penalties for BAC 0.15 or above while under age 18
First offense: $1,000-$2,000 fine, up to 9 months of jail time, 6-month minimum interlock requirement Second offense: $2,000-$4,000 fine, up to 12 months of jail time, 2-year minimum interlock requirement Third and fourth offenses: Minimum $4,000 fine, plus the above penalties |
| Georgia | 0.15 | 0.15 BAC on first offense receives same sentence as those convicted of second offense: $1,000-$3,000 fine, 6-12 months of jail time (judge may suspend all but 15 days), 5-year license revocation, 1-year minimum interlock requirement. |
| Hawaii | None | None |
| Idaho | 0.2 | First offense: Up to $2,000 fine, 10 days to 1 year of jail time, 1-year license suspension (no restricted license available), interlock required after suspension, alcohol evaluation and treatment, Idaho SR-22 additional insurance requirement
Second offense: Felony offense, up to $5,000 fine, minimum 30 days in county jail, up to 5 years in state penitentiary, 1-5 years of license suspension (no restricted license available), interlock required after suspension, alcohol evaluation and treatment, Idaho SR-22 additional insurance requirement |
| Illinois | 0.16 | First offense: Minimum $500 fine, 100 hours of community service
Second offense: Minimum $1,250 fine, 2 days of mandatory imprisonment Third offense: Minimum $2,500 fine, 90 days of mandatory imprisonment Fourth and additional offenses: Minimum $5,000 fine |
| Indiana | 0.15 | First offense: Up to $5,000 fine, up to 1 year of jail time |
| Iowa | 0.15 | First offense: 48 hours jail time |
| Kansas | 0.15 | First offense: 1-year license suspension (as opposed to 30 days)
Second offense: 2-year interlock requirement following suspension Third offense: 3-years interlock requirement following suspension Fourth offense: 4-years interlock requirement following suspension |
| Kentucky | 0.15 | Increased minimum jail time |
| Louisiana | 0.15 and 0.2 | 0.15 or above: Enhanced penalties, at court’s discretion
First offense, 0.2 or above: $750-$1,000 fine, 2-year license suspension (as opposed to 1 year) Second offense, 0.2 or above: 4-year license suspension |
| Maine | 0.15 | Minimum 48 hours of imprisonment |
| Maryland | 0.15 | Ineligible for modification of a license suspension or issuance of a restrictive license |
| Massachusetts | 0.2 | 0.2 or above: Mandatory alcohol treatment program |
| Michigan | 0.17 | First offense: $200-$700 fine, up to 180 days of jail time (as opposed to 90), 1-year license suspension (as opposed to 6 months), mandatory interlock |
| Minnesota | 0.16 | Unless maximum bail is imposed, must agree to abstain from alcohol use and submit to daily monitoring of alcohol levels before release from detention |
| Mississippi | None | None |
| Missouri | 0.15 and 0.2 | 0.15 to 0.19: 2 days of mandatory imprisonment
0.2 or above: 5 days of mandatory imprisonment 0.15 or above: Required drug or alcohol education/rehabilitation program |
| Montana | 0.16 | First offense: Up to $1,000 fine, 48 hours to 1 year of imprisonment
Second offense: $2,500 fine, 15 days to 1 year of imprisonment Third offense: $5,000 fine, 40 days to 1 year of imprisonment |
| Nebraska | 0.15 | First offense: Additional $500 fine, 1-year license revocation (as opposed to 2-6 months)
Second offense: Additional fine up to $1,000, license revocation up to 15 years Third offense: Felony charge, additional fine up to $10,000, up to 5 years of imprisonment (as opposed to 1 year), license revocation of 5-15 years (as opposed to 2-15) Fourth offense: Class III felony charge, additional fine up to $25,000, up to 20 years of imprisonment, possible use of alcohol-monitoring device for minimum 6 months Fifth and subsequent offenses: Class II felony charge, additional fine up to $25,000, up to 50 years of imprisonment |
| Nevada | 0.18 | First and second offenses: 12-36 months of mandatory interlock (as opposed to 3-6 months), alcohol treatment |
| New Hampshire | 0.16 | Class A misdemeanor, 5 days to 1 year of jail time, $750-$2,000 fine, interlock required for first offense |
| New Jersey | 0.15 | Mandatory interlock |
| New Mexico | 0.16 (with mandatory jail time for all offenses) | Aggravated penalty at court’s discretion |
| New York | 0.18 | First offense: $1,000-$2,500 fine, minimum 1-year license revocation (as opposed to 6 months)
Second and subsequent offenses: Minimum 18-month license revocation |
| North Carolina | 0.15 | First offense: 1-year interlock requirement |
| North Dakota | 0.18 | First offense: 180-day license suspension (as opposed to 91 days), minimum $750 fine increase, at least 2 days of imprisonment (court may convert each day into 10 hours of community service)
Second offense: 2-year license suspension Third offense: 3-year license suspension |
| Ohio | 0.17 | Up to $1,075 fine, up to 6 months in jail, license suspension of 6 months to 3 years |
| Oklahoma | 0.15 | 480 hours of community service, minimum 1 year of supervision and periodic testing
First offense: 18-month interlock requirement |
| Oregon | 0.15 | Minimum $2,000 fine (as opposed to $1,000) |
| Pennsylvania | 0.1 and 0.16 | First offense, 0.1 to 0.15: $500-$5,000 fine, minimum 48 hours of jail time, 12-month license suspension
First offense, 0.16 and above: $1,000-$5,000 fine, minimum 72 hours of jail time, 12-month license suspension Second offense, 0.1 to 0.15: $750-$5,000 fine, minimum 30 days of jail time, 12-month license suspension Second offense, 0.16 and above: Minimum $1,500 fine, minimum 90 days of jail time, 18-month license suspension Third offense, 0.1 to 0.15: $1,500-$10,000 fine, minimum 90 days of jail time, 18-month license suspension Third offense, 0.16 and above: Minimum $2,500 fine, minimum 1 year of jail time, 18-month license suspension |
| Rhode Island | 0.1 and 0.15 | First offense, 0.1 to 0.14: $100-$400 fine plus $500 highway assessment fine, 3-12 months of license suspension
First offense, 0.15 and above: $500 fine plus $500 highway assessment fine, 3-18 months of license suspension, minimum 20 hours of public community restitution (as opposed to 10) Second offense, 0.15 and above: Minimum $1,000 fine plus $500 highway assessment fine, 6 months to 1 year of jail time, 2-year license suspension Third offense, 0.15 and above: $1,000-$5,000 fine plus $500 highway assessment fine, 3-5 years of jail time, 3-year license suspension |
| South Carolina | 0.16 |
First offense, 0.16 and above: $1,000 fine, 30-90 days of jail time (possible community service instead)
Second offense, 0.16 and above: $3,500-$6,500 fine, 90 days to 3 years of jail time Third offense, 0.16 and above: $7,500-$10,000 fine, 6 months to 5 years of jail time Fourth offense, 0.16 and above: 3-7 years of jail time |
| South Dakota | 0.17 | May be sentenced to a 24/7 continuous sobriety monitoring program and must undergo a court-ordered evaluation by a licensed professional |
| Tennessee | 0.2 | Minimum 7 days of jail time (as opposed to 48 hours) |
| Texas | 0.15 | 1 year interlock requirement |
| Utah | 0.16 | 1-year interlock requirement (at judge’s discretion for lower BACs) |
| Vermont | 0.16 | Prohibited from driving with a BAC of 0.02 or higher for 3 years after conviction (as opposed to 0.08), during which driving with a BAC of 0.02 or higher is a DUI and penalized as such |
| Virginia | 0.15 and 0.2 | First offense, 0.15 to 0.2: Additional minimum 5 days of jail time
First offense, 0.2 and above: Additional minimum 10 days of jail time Second offense, 0.15 to 0.2: Additional minimum 10 days of jail time Second offense, 0.2 and above: Additional minimum 20 days of jail time, minimum $500 fine |
| Washington | 0.15 | First offense: 1-year license revocation
Second offense: 900-day license revocation Third offense: 4-year license revocation |
| West Virginia | 0.15 | Mandatory interlock period |
| Wisconsin | 0.17, 0.2, and
0.25 |
0.17 to 0.199: Minimum and maximum fines doubled
0.2 to 0.249: Minimum and maximum fines tripled 0.25 or above: Minimum and maximum fines quadrupled First offense, 0.15 or above: 1-year minimum interlock requirement |
| Wyoming | 0.15 | Interlock required for 6 months after first offense |
Will I have to use an interlock if this is my first DUI?
Whether you need to use an interlock after your first DUI conviction depends on the state where you live.
In the following 30 states, first time offenders must install an interlock in their vehicle:
- Alabama
- Arizona
- Arkansas
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Hawaii
- Idaho
- Illinois
- Iowa
- Kansas
- Kenucky
- Louisiana
- Maryland
- Mississippi
- Nebraska
- New Hampshire
- New Jersey
- New Mexico
- New York
- Oklahoma
- Oregon
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- Washington
- West Virginia.
In the following eight states, only high first-time offenders with a high BAC (between 0.1 and 0.17) need to install an interlock:
- Florida
- Michigan
- Minnesota
- North Carolina
- Pennsylvania
- Rhode Island
- South Carolina
- Wyoming
The following five states require an interlock for repeat offenders only:
- Georgia
- Maine
- Massachusetts
- Missouri
- Ohio
The remaining seven states do not have statewide interlock requirements, but judges can order use at their discretion, including for first time offenders:
- California
- Indiana
- Montana
- Nevada
- North Dakota
- South Dakota
- Wisconsin
Managing Editor & Industry Analyst
Maya Afilalo holds over 10 years of professional experience in writing, communications, and research, which she leverages to provide accurate and reliable information to empower consumers. In addition to overseeing content production, Maya has herself written many articles on auto insurance costs, company comparisons, state laws and requirements, and other topics. She is committed to helping consumers navigate the complex world of car insurance with clarity and confidence. Maya holds a bachelor’s degree from the University of Pennsylvania and a master’s from North Carolina State University.
Citations
Alcohol Ignition Interlocks. NHTSA. (2025).
https://www.nhtsa.gov/book/countermeasures-that-work/alcohol-impaired-driving/countermeasures/other-strategies-behavior-change/alcohol-ignitionHow do I get my license back after a DUI?. madd. (2025).
https://www.myduiattorney.org/questions/how-do-i-get-my-license-back-after-a-duiSTATE BY STATE LEGAL BLOOD ALCOHOL LIMIT (BAC). Andy Green Attorney at Law. (2025)
https://www.andygreenlaw.com/dui/state-by-state-bac/Delaware DUI Laws Overview. DUI Process. (2025).
https://www.duiprocess.com/delaware-dui-laws-penalties/State-by-State DUI Penalties. FindLaw.
https://www.findlaw.com/dui/laws-resources/state-by-state-dui-penalties.htmlDOES AN INTERLOCK AFFECT INSURANCE?. Alcolock.
https://alcolockusa.com/faq/does-an-interlock-affect-insurance/
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