Independent Guide
Ignition Interlock Device: The Honest Guide
What it costs, what daily life is like, and what IID companies don't tell you.
Last updated: March 4, 2026
Quick Answer
An ignition interlock device (IID) is a breathalyzer wired into your car's ignition that you blow into before starting the engine. If it detects alcohol, your car won't start. IIDs cost $70–$150 to install and $60–$100/month to lease. They're required in most states for DUI offenders, sometimes even for first offenses. Here's what it's actually like to live with one — from someone who isn't trying to sell you a device.
How an IID Works
The device is wired into your car's ignition system by an authorized installer. Every time you want to start your car:
1
Pick up the handset and blow a steady breath for 4–6 seconds
2
The device analyzes your breath alcohol content (BrAC)
3
If you're below the threshold (usually 0.02–0.025%), the car starts
4
If you're above the threshold, the car won't start and a lockout period begins
5
While driving, the device prompts random 'rolling retests' — you pull over and blow again
Every test — pass or fail — is logged with a timestamp. This data is downloaded at your monthly calibration and shared with the court, probation, or your state's DMV.
What It's Actually Like to Live With One
This is the section you won't find on any interlock company's website. Here's the reality:
The Morning Routine
Add 3–5 minutes to your morning. Pick up the handset, blow a steady breath, wait for the result, then start the car. Then a rolling retest will come within 5–15 minutes. If you're running late for work, that extra time feels like an eternity. On cold mornings, the device takes longer to warm up. You learn to budget the extra time automatically — but the first few weeks are frustrating.
Using It in Front of Other People
This is the part nobody prepares you for. Blowing into a device in front of coworkers in the parking lot. Your kids asking what that thing is. A first date seeing it. A friend riding with you when the rolling retest beeps. It's embarrassing. That's the honest truth. Most people develop a quick, matter-of-fact explanation: "It's a court requirement. No big deal." Some people just say "It's a breathalyzer thing" and change the subject. It gets easier. It never becomes fun.
False Positives — This Is a Real Problem
IID devices are sensitive. Things that can trigger a false positive:
- • Mouthwash — the #1 cause. Most contain 10–25% alcohol. Switch to alcohol-free immediately.
- • Hand sanitizer — fumes in an enclosed car can register.
- • Kombucha — contains trace fermentation alcohol.
- • Fresh bread / yeast products — yeast produces trace alcohol vapors.
- • Vanilla extract — 35% alcohol by volume.
- • Some medications — cough syrups, Nyquil, etc.
- • Energy drinks — some contain trace fermentation byproducts.
Pro tip: Rinse your mouth with water and wait 15 minutes before any test. Make this a habit. A false positive is logged the same as a real one — you'll have to explain it to the court.
What Happens When You Fail a Test
Your car won't start. A lockout period begins (5–30 minutes). The failure is logged with a timestamp. After the lockout, you can try again. If you fail again, the lockout period increases. After multiple failures, the device may enter a "permanent lockout" requiring a provider visit to reset ($50–$150). Every failure is reported to your monitoring authority at your next calibration — or in real-time if you have a cellular-connected device.
Calibration Appointments
Every 30–60 days, you drive to your provider's service center for calibration. They download your data, recalibrate the sensor, and check for tampering. Appointments take 15–30 minutes. They're during business hours, which means time off work. Miss a calibration and the device will lock you out — plus it's a violation.
Cold Weather & Battery Issues
IID devices can malfunction in extreme cold (below 0°F). The sensor needs to warm up before it can get an accurate reading. In winter, start your routine 10–15 minutes early. If your car battery dies while the device is installed, it may log a "power disconnect" event that looks like tampering. Keep your battery healthy and drive regularly.
IID Cost Breakdown
Installation
One-time. Some providers run discounts.
$70 – $150
Monthly Lease
The core recurring cost.
$60 – $100
Monthly Calibration
Often included in lease; sometimes separate.
$0 – $50
Removal Fee
One-time at end of requirement.
$50 – $100
Violation Fees
Per failed test or missed calibration.
$50 – $100/each
Lockout Reset Fee
If the device locks you out.
$50 – $150
Total Cost Estimates
6 Months
$500 – $850
12 Months
$800 – $1,500
24 Months
$1,500 – $2,800
Some providers offer income-based discounts or state-assistance programs. Ask about financial hardship options.
Major IID Providers
DUI911 is not affiliated with any interlock provider. This comparison is based on publicly available information.
| Provider | Locations | Coverage | Notes |
|---|---|---|---|
| Intoxalock | 5,500+ | All 50 states | Largest network. Owned by Consumer Safety Technology. Also owns DUI.org. |
| Smart Start | 2,500+ | All 50 states | Second-largest. Generally competitive pricing. |
| LifeSafer | 1,700+ | Most states | Subsidiary of Alcohol Sensors International. |
| Draeger | Varies | Select states | German manufacturer. Known for device quality. |
| Guardian Interlock | 1,000+ | Most states | Part of Alcohol Detection Systems. |
How to choose: Check which providers are approved in your state (not all are). Compare pricing — get quotes from at least 2–3. Ask about hidden fees, calibration costs, and what happens if you move or change vehicles. Choose a provider with a service center near your home or work.
State IID Requirements
| State | When Required | Duration |
|---|---|---|
| Alabama | Required for a first DUI at 0.15 or more, with a passenger under 14, after a refusal, or after a crash that injured someone, and for every repeat DUI. For a first DUI under 0.15 you may choose it to stay the suspension. | ALEA lists the interlock term by conviction: 90 days for a first offense under 0.15, 1 year for a first offense at 0.15 or more, 2 years for a second, 3 years for a third, and 4 years for a fourth or later. A refusal adds one year (except on a first conviction), and violations extend the term by six months. For a first offense under 0.15, the interlock is a voluntary way to stay the suspension. |
| Alaska | Required by the court after a DUI conviction involving alcohol and after a refusal conviction, starting when you get your license back. Also required for a limited license. The requirement is waived when you drive in a community on the state's list of places off the road system. | Minimums: 6 months after a first conviction, 12 months after a second, 18 months after a third, 24 months after a fourth, 30 months after a fifth, 36 months after a sixth or later, and 60 months after a felony. A limited license is available after 30 days on a first offense and 90 days on later ones, with interlock installed first. |
| Arizona | Required after any DUI conviction once your driving privilege is restored. A Special Ignition Interlock Restricted Driver License (SIIRDL) can also let you drive during a suspension. | At least 12 months for a standard DUI (may be reduced to 6 months in some cases), measured from when your privilege is eligible for reinstatement or MVD receives the conviction, whichever is later. Extreme, super extreme and aggravated DUI carry longer periods. |
| Arkansas | Required for DWI alcohol suspensions. You file a Confirmation of Interlock Requirement with Driver Control. | For a period equal to the license suspension. |
| California | Under the statewide ignition interlock program, a second or later DUI conviction requires an interlock to reinstate. For a first offense without injury, the court may order one for up to 6 months, or you may choose one to get a restricted license. | Without injury (Veh. Code §23152): 12 months with one prior within 10 years, 24 months with two, 36 months with three or more. With injury (§23153): 12 months with no priors, 24 with one, 36 with two. The term can be reduced by credit for time with an interlock during the APS suspension. The program runs through January 1, 2033. |
| Colorado | Required for Persistent Drunk Drivers: a BAC of 0.15 or more, a refusal, or two or more convictions. First offenders under 0.15 can use interlock to reinstate early. | At least 2 years for Persistent Drunk Drivers, and 2 to 5 years after a revocation for multiple DUI or DWAI convictions. A first-time offender who reinstates early keeps the interlock for the rest of the revocation. Drivers under 21 cannot apply for early reinstatement until the license has been revoked for one year. |
| Connecticut | Required after every administrative per se suspension and every DUI conviction, including first offenses and refusals. | Per se, age 21+: 6 months, 1 year, then 2 years for first, second, and third suspensions. Under 21 or refusal: 1, 2, then 3 years. Conviction: 1 year for a first, 3 years for a second, and lifetime (reviewable after 15 years) for a third. |
| Delaware | Mandatory for all DUI offenders, first and repeat, for offenses on or after February 1, 2015. First Offender Election participants can apply for an interlock license right away. | First offense: you can apply for an interlock license after 30 days of revocation (45 days if your BAC was 0.15 or more), and the device stays on for at least 12 months (17 months at 0.15–0.19, 23 months at 0.20 or more). First Offender Election: you can apply right away, and the device stays on for at least 4 months. Second offense: 16 to 28 months. Third: 21 to 33 months. Fourth or later: 54 months. The longer figures apply at higher BAC. |
| Florida | Required for a first DUI with a BAC of 0.15 or more or a passenger under 18 in the vehicle, and for second and later convictions. For a first DUI at 0.08 or more, the court may order it. | At least 6 months for a first offense with 0.15+ or a passenger under 18 (2 years for a second such offense); otherwise at least 1 year for a second offense, 2 years for a third, and 5 years for a fourth or later. |
| Georgia | Required for a second or later DUI within 5 years, unless the court exempts you for financial hardship. After an ALS, you can choose an Ignition Interlock Device Limited Permit instead of a hearing. | 12 months for habitual violators once eligible to reinstate. DDS cannot issue an interlock permit until it has the 1205 form and the device is installed. |
| Hawaii | The criminal sentence for a first or second OVUII includes installing an ignition interlock device. On the administrative side, you need an interlock and an Ignition Interlock Permit only if you want to drive during the revocation. | The interlock runs with the revocation period set in your Ignition Interlock Permit. Habitually OVUII requires an interlock in every vehicle you drive during a 3-to-5-year revocation. |
| Idaho | On a first DUI, the court must require an interlock for 1 year after the suspension ends, unless it grants an exception. It is also required after a second or later DUI, after a refusal, and, according to ITD, after any ALS suspension unless the court waives it. | A period ending 1 year after the suspension ends, installed within 10 days after the absolute suspension period on a first DUI. After a second or later conviction, you may drive only a vehicle with a working interlock after the 1-year suspension. The device blocks starting at 0.025. |
| Illinois | A first offender can drive during the Statutory Summary Suspension only with a Monitoring Device Driving Permit (MDDP) and a Breath Alcohol Ignition Interlock Device (BAIID). Repeat offenders need a BAIID to get a Restricted Driving Permit after revocation. | The MDDP cannot take effect before the 31st day of the suspension and lasts for the rest of it. BAIID periods for repeat offenders are set by the Secretary of State when it grants relief. |
| Indiana | Not automatic. A court may require an ignition interlock as a condition of specialized driving privileges or probation. From July 1, 2026, interlocks may be ordered only when the OWI involved alcohol. | Time driving with an interlock as a condition of specialized driving privileges is credited toward the suspension. |
| Iowa | Required for any temporary restricted license (TRL) during an OWI revocation. After two or more OWI offenses, an interlock is also required once your license is reinstated. | For the life of the TRL. After two or more OWI offenses, 365 days on all vehicles you drive after reinstatement. |
| Kansas | Required after the suspension period for test failures, refusals, and DUI convictions. The interlock must be approved by the Kansas Highway Patrol and paid for by you. | First test failure at 0.15 or more: 1 year. Second occurrence: 1 year. Third: 2 years. Refusals: 2 to 4 years. Proof of installation for the whole period is required before full reinstatement. |
| Kentucky | Optional for most drivers through the Kentucky Ignition Interlock Program (KIIP). Choosing it shortens the suspension. The court may also require it during pretrial suspension. | You must stay violation-free for 90 consecutive days (first offense) or 120 consecutive days (second and later). Apply with form TC 94-175. |
| Louisiana | Required on a first offense at 0.15 or more. After a refusal, OMV requires an interlock on reinstatement or with a hardship license when the arrest involved a crash with moderate or serious injury, a child 12 or younger in the vehicle, or a prior alcohol violation on your record. | On a first offense at 0.15 or more, the interlock is required for the first 12 months of the two-year suspension. OMV lists 365 days of interlock for a first refusal when interlock applies. |
| Maine | Interlock is the path to early reinstatement. You petition the Secretary of State and get written approval before installing the device ($50 application fee). | First OUI: reinstate after 30 days of the 150-day suspension with interlock for the rest of the term. Second: after 9 months, interlock for 2 years. Third: after 3 years, interlock for 3 years. Fourth or more: after 4 years, interlock for 4 years. |
| Maryland | Under Noah’s Law, a DUI conviction, a DWI with a child under 16 in the car, and a test refusal require the Ignition Interlock Program. Since October 1, 2024, a probation before judgment for DUI or DWI also requires it. You can also elect it to keep driving during an MVA suspension. | 180 days for a BAC of 0.08 to under 0.15; 1 year for 0.15 or more or a refusal. Repeat offenses and court or MVA orders can require longer. |
| Massachusetts | Under Melanie’s Law (c. 90 §24½), an interlock is required for anyone with two or more OUI convictions or alcohol-education assignments who gets a hardship license or has their license reinstated. | The device stays on for the whole hardship license period and for 2 years after full reinstatement for multiple offenders. |
| Michigan | Required for a restricted license after 45 days of a High BAC suspension. Repeat offenders whose licenses are revoked usually need an interlock when the Secretary of State restores driving privileges after a hearing. | For High BAC, the interlock stays on for the rest of the 1-year suspension. After a revocation, interlock terms are set by the Office of Hearings and Administrative Oversight when it grants a restricted license. |
| Minnesota | Required for every repeat offender and for a first offense at 0.16 or more to regain driving privileges. First offenders under 0.16 can choose interlock instead of sitting out the 90-day revocation. | Under the 2025 law: 2 years with one prior in 20 years, 6 years for two, and 10 years for three or more. Program participants must also complete licensed substance use disorder treatment. |
| Mississippi | On a first alcohol DUI, you either install an interlock and hold an interlock-restricted license or serve a 120-day suspension. The court can order an interlock-restricted license instead of suspension on repeat offenses, and after a third offense only an interlock-restricted license is available once you are released. | The court sets the period for the interlock device (§63-11-31). A first-offense suspension is 120 days; after a third offense, only an interlock-restricted license is available for 3 years after release, and for 10 years after a fourth or later offense. |
| Missouri | Required to reinstate if your record shows more than one alcohol- or drug-related enforcement contact, or on a first conviction with a BAC of 0.15 or more, or with injury or property damage. Also required for a restricted driving privilege after a refusal. | At least 6 months from the reinstatement date. Courts may order longer. |
| Montana | For a second or later DUI, the court orders the 24/7 sobriety program, an interlock if it recommends a probationary license, or forfeiture of the vehicle. Interlock is discretionary on a first offense. | The statute does not set a fixed interlock period. It is tied to a probationary license the court recommends. The 24/7 program centers on twice-daily breath testing about 12 hours apart. |
| Nebraska | Courts order an ignition interlock permit and device for the revocation period on DUI convictions. After an ALR revocation, you can apply for an interlock permit to drive. | On a first offense the interlock is required for the revocation period (6 months, 60 days on probation, 1 year at 0.15 or more). On a second offense there is a 45-day no-drive period, then an interlock for at least 1 year. For a third or later offense the court may order an interlock after a 45-day no-drive period. |
| Nevada | A court must order it after any DUI conviction, including a first offense, with narrow exceptions (unable to give a deep lung breath sample, certified by a doctor, or living more than 100 miles from an interlock provider). It is also required to drive during the administrative revocation, under NRS 484C.210. | 185 days for a first offense, 1 year for a second within 7 years, and 3 years for a felony DUI or DUI causing death or substantial bodily harm. The clock starts when the DMV issues your ignition interlock privilege. The device must be installed within 14 days of the order. |
| New Hampshire | Required by the court for an aggravated DWI or a second or later DWI. | At least 12 months and up to 2 years, starting after the revocation ends, in any vehicle you drive regularly. You pay for it, and proof of installation is required before your license is restored. |
| New Jersey | Required for nearly every DWI and refusal conviction under the 2019 law, including first offenses at 0.08 to under 0.10. You may not drive until the device is installed. | First offense: 3 months (0.08 to under 0.10); 7 to 12 months (0.10 to under 0.15); during the forfeiture and 12 to 15 months after (0.15 or more). A first refusal: during the forfeiture and 9 to 15 months after. Second or later offense or refusal: during the forfeiture and 2 to 4 years after. You may install an interlock after arrest and before conviction. For a 0.15 or more first offense, a second, or a third, an early-installed interlock earns 1 day of credit against forfeiture for every 2 days installed, except when the violation caused serious bodily injury. The interlock law runs until January 1, 2029. |
| New Mexico | Required after every DWI conviction, including a first. To reinstate, you must hold an ignition interlock license with a device installed for at least 6 months. | 1 year for a first conviction, 2 years for a second, 3 years for a third, and for life after a fourth or later. |
| New York | Required for every DWI and Aggravated DWI conviction under Leandra’s Law, including first offenses. The court must order it as part of probation or a conditional discharge. | At least 12 months, unless the court allows earlier removal. It must be installed in any vehicle you own or operate. |
| North Carolina | Required to get your license back after a DWI conviction with an alcohol concentration of 0.15 or more, and after certain repeat convictions. A judge may also require it as a condition of a limited driving privilege. | The interlock stays for 1 year from restoration if the original revocation was 1 year, 3 years if it was 4 years, and 7 years if it was permanent. The restored license also carries a restriction against driving with an alcohol concentration of 0.02 or more. |
| North Dakota | North Dakota relies on the 24/7 sobriety program rather than mandatory interlock. NDDOT may require an interlock as a condition of a temporary restricted license, and the Attorney General may allow interlock instead of twice-daily breath tests in 24/7. | If you are in 24/7, NDDOT issues a temporary restricted license after 14 days of the suspension. You must apply and file proof of financial responsibility and 24/7 participation. |
| Ohio | Required to drive with a high test (0.17 or more) when the court grants driving privileges, and on repeat offenses. A first offender can petition for unlimited driving privileges with an interlock; if granted, the court suspends the jail term. | Length is set by the court order. Restricted yellow “party plates” are an alternative the court can order. |
| Oklahoma | IDAP itself requires an approved ignition interlock. After a conviction, Oklahoma also requires interlock on vehicles you own or that are registered to you, including for aggravated DUI. | IDAP runs at least 180 days for a first revocation, 1 year for a second and 2 years for a third, and must end with a violation-free period (at least 90 days under SB 921). After conviction, the Highway Safety Office says interlock is 18 months for first-time offenders. |
| Oregon | Required after a DUII conviction, and during DUII diversion if your BAC was 0.08 or more, you refused a test, or drugs were found. Also required to get a hardship permit during a DUII suspension. | After the conviction suspension ends: 1 year for a first conviction and 2 years for a second or later conviction. Five years applies if the DUII came with a homicide or first-degree assault conviction from the same episode, or if privileges revoked for a third DUII are later restored. During diversion, you can ask the court to remove it after 6 months of compliance. |
| Pennsylvania | Required for a second or later DUI. First offenders suspended at the High or Highest Rate, and drivers suspended for a refusal, can drive sooner with an Ignition Interlock Limited License. | One year after the suspension ends for repeat offenders. Driving without the device or tampering with it extends the requirement by 12 months. |
| Rhode Island | On a first DUI the judge may bar you from driving without an interlock and/or blood and urine testing, and must do so at 0.15 or more. The judge must order it on a second or later DUI and on a second or later refusal; on a first refusal it is optional. A hardship license is only granted by the sentencing court and only with interlock or blood and urine testing. | First DUI: a minimum 30-day suspension, then interlock or testing for 3 months to 1 year. A second DUI: a 45-day minimum suspension, then 6 months to 2 years of interlock or testing. A third DUI: a 60-day minimum suspension, then 1 to 4 years. Report a court-granted hardship license to the DMV Adjudication Office to get the restriction added. |
| South Carolina | Since May 19, 2024, the “All Offender” law requires every driver convicted of DUI to join the Ignition Interlock Device Program, regardless of BAC. Interlock can also end a refusal or 0.15+ administrative suspension early. | Length depends on the offense and BAC. For an administrative suspension, the device stays on for the time remaining on the suspension. |
| South Dakota | Not automatic on a first DUI. Anyone on probation, parole, or a suspended sentence for DUI must have at least one monitoring tool: the 24/7 Sobriety Program, an ignition interlock, an alcohol monitoring bracelet, or similar. | Length is set by the court as part of supervision. Many people are also put on 24/7 twice-daily breath testing (around 7 a.m. and 7 p.m. at the sheriff’s office) as a bond condition after arrest. |
| Tennessee | Required to drive on a restricted license during any DUI revocation, and on a restricted license after an implied consent violation. You need a court Order for Restricted Driver License (ORDL), proof of SR-22 insurance, and proof of installation. | The interlock is required for the full revocation period, with a 365-day minimum. Revocation periods: 1 year (1st), 2 years (2nd), 6 years (3rd), 8 years (4th or later). |
| Texas | Required as a condition of community supervision for a second or later DWI, and for a first DWI with a BAC of 0.15 or higher. Courts can also order it as a bond condition. | Length is set by the court order (bond or community supervision). An interlock-restricted license may be needed to drive during a suspension. |
| Utah | The court must order an interlock as a condition of probation after a DUI conviction unless it finds on the record that one is not necessary. For drivers under 21 it is mandatory. At 0.16 or more the court must order an interlock, an ankle monitor, or home confinement, or explain why none fits. A second DUI within 10 years requires an interlock on every vehicle you own or drive. | 18 months after a conviction for drivers 21 and older; 3 years for drivers under 21 at arrest. Longer for felony and repeat convictions. |
| Vermont | An ignition interlock RDL lets you drive during a suspension in an interlock-equipped vehicle (not a commercial vehicle). It is optional for a first offense and required before reinstatement for a second or later offense. Refusal cases must wait 30 days (first), 90 days (second) or 1 year (third or later) before applying, and cases involving death or serious bodily injury must wait 1 year. | A first offender who chooses an RDL must operate under it for the length of the suspension (90 days for a first alcohol failure) before reinstatement. A second offender needs 18 months on an RDL. A third or later offender must drive on an interlock RDL for at least 3 years before the Total Abstinence program can reinstate them. Violations and failed retests can extend these periods. |
| Virginia | Required as a condition of any restricted license after a DUI conviction, and as a condition of getting your full license back after a second offense or a first offense at 0.15 or more. | At least 6 months with no violations before the interlock can come off. The court and VASAP monitor compliance. |
| Washington | Required after a DUI or Physical Control conviction or deferred prosecution. An ignition interlock driver license lets you drive during a DOL suspension if you install a device. | 1 year for a first violation, 5 years for a second and 10 years for a third or later. Carrying a passenger under 16 adds 6 months. |
| West Virginia | The Motor Vehicle Alcohol Test and Lock Program lets many revoked drivers drive with an interlock after a shorter hard revocation. It is optional for most first offenses and the route back to driving for many repeat offenders. | First offense at 0.08 to 0.149: 15 days revoked, then 125 days of interlock. At 0.15 or more: 45 days, then 270 days. First refusal: 45 days, then 1 year. |
| Wisconsin | Required for a first OWI with an alcohol concentration of 0.15 or more, for every repeat OWI, and after an improper refusal. | The court sets the length of the interlock order. You also need an interlock-restricted occupational license to drive during a revocation if one is ordered. |
| Wyoming | Required after a first DUI conviction at 0.15 or more, and after every second or later conviction. The court may order the 24/7 sobriety program as an alternative to, or in addition to, the interlock. | 6 months for a first conviction at 0.15 or more, 1 year for a second, 2 years for a third, and for life after a fourth or later (you may ask the court to remove it after 5 years). The interlock time starts once the interlock restricted license is issued. |
From each state’s guide, which links the official sources. Educational information, not legal advice.
What IID Companies Don't Tell You
Interlock companies are in the business of selling devices, not giving you the full picture. Here's what they leave out:
Hidden Fees Add Up Fast
The advertised monthly rate is just the start. Calibration fees, data download fees, violation reset fees, early removal fees, late payment fees, device replacement fees if it malfunctions — they all stack up. Ask for a complete fee schedule in writing before you sign anything. The real monthly cost is often 20–40% higher than the quoted lease rate.
Violations Can Extend Your Requirement
A failed test, a missed calibration, or a power disconnect event can be reported as a violation. In many states, violations during your IID period can reset the clock on your requirement — meaning you start the monitoring period over from scratch. One false positive from mouthwash could add months to your time with the device.
Your Data Is Shared
Every test, every failure, every retest — it's all logged and shared with the court, your probation officer, and your state's DMV/MVD. If you have a cellular-connected device, some of this data is transmitted in real-time. You have no privacy on this device. Act accordingly.
Camera-Equipped Devices
Some states require — and some providers offer — devices with built-in cameras that photograph you during every breath test. This is to prevent someone else from blowing into the device for you. The photos are included in your compliance reports. You may not have a choice about whether your device has a camera.
Early Termination Isn't Simple
Even if your court requirement ends, removing the device requires proper documentation, a provider appointment, and sometimes court or DMV approval. If you remove the device without going through the proper channels, it can be treated as tampering — a criminal offense. Follow the process exactly.
Frequently Asked Questions
Yes. Many mouthwashes contain 10-25% alcohol — far more than beer. If you use mouthwash and blow into your IID within 10-15 minutes, you will likely register a positive. Use alcohol-free mouthwash only. This is the #1 cause of false positives and it can trigger a violation report to the court.
The device logs the failure and your car won't start. You'll typically get a short lockout period (5-15 minutes) before you can try again. The failure is recorded and reported to your monitoring authority — court, probation, or DMV. Multiple failures can extend your IID requirement or trigger additional penalties.
This is a crime in most states — called 'circumvention.' Many modern IID devices have cameras that photograph you during each test. Getting caught means additional criminal charges, extended IID requirements, and potential jail time. It's not worth the risk.
While driving, the device will beep and prompt you to blow — usually within 5-15 minutes of starting the car, then at random intervals. You have a few minutes to find a safe place to pull over and test. If you fail or skip the retest, the device logs a violation. Your car won't shut off mid-drive, but your horn may honk and lights may flash until you pull over and test.
It depends on the state where you were arrested and your offense. Some states set the length by law; others leave it to the court or licensing agency. Repeat offenses usually mean a longer requirement, and some states extend it if you have violations during the monitoring period. The state table above summarizes each state's rules.
No — the IID is installed in one specific vehicle. You can only legally drive that vehicle during your requirement period. Driving any vehicle without an IID installed is a violation that can result in additional criminal charges and extended requirements. Some states allow you to install devices in multiple vehicles for an additional fee.
IID devices can malfunction in very cold weather (below 0°F). The device may take longer to warm up, give inaccurate readings, or fail to start. Most providers recommend starting your car 10-15 minutes early in winter. If the device malfunctions due to cold, contact your provider immediately — they can document it as a technical issue rather than a violation.
IID devices draw a small amount of power even when the car is off. If your battery is old or weak, this can drain it — especially in cold weather. If your battery dies and the device loses power, it may log a 'tampering' event that you'll need to explain. Keep your battery in good condition and drive the vehicle regularly.
DUI911 is not affiliated with any interlock provider. This guide is independently written. We don't receive referral fees, commissions, or compensation from any IID company. Our only goal is giving you honest information.
State-Specific Interlock Guides
How Much Does a DUI Cost?
Full cost breakdown including IID, insurance, fines, and hidden costs