Indiana Ignition Interlock Device: Costs, Violations & Defenses

In Indiana, an ignition interlock device is a court-ordered breathalyzer wired into your vehicle’s ignition, typically imposed as a condition of specialized driving privileges after an operating-while-intoxicated conviction. You pay for installation and monthly service, you blow into it before the car will start and again at random points during every trip, and violating the order is a Class A misdemeanor with up to a year in jail.

When a Court Orders an Interlock

The requirement is not automatic. Under IC 9-30-5-16, a court granting specialized driving privileges may add the condition that you only operate a vehicle equipped with a certified ignition interlock device.¹ The judge weighs the facts of your case, including BAC, prior record, and aggravating circumstances.

Repeat offenders are the most likely to be ordered to install one. Indiana treats a second OWI within seven years as a Level 6 felony,² and courts routinely attach interlock conditions when granting any driving privileges to someone with that kind of history. Indiana also allows interlock conditions for offenders with a prior conviction within five or ten years who seek restricted driving privileges.³ The length of the interlock term is set by the court and cannot exceed the maximum prison sentence for the underlying offense.

One narrow exception: the court cannot order an interlock installed on an employer-owned vehicle if you were convicted of OWI and are covered by a labor agreement that bars operating your employer’s vehicle after an alcohol-related offense.¹ That protects the employer’s fleet but does not exempt you from the requirement on your personal vehicle.

How the Device Works

Startup Breath Test

Before the engine will start, you blow into the device. If it detects alcohol at or above 0.02 grams per 100 milliliters of blood (or the breath equivalent), the vehicle will not start.⁴ That threshold sits far below the 0.08 legal limit, so even a small amount of alcohol will lock you out.

Rolling Retests

Startup is only the beginning. Indiana’s administrative rules require the device to prompt a random retest within three to fifteen minutes after the vehicle starts, then again at random intervals of fifteen to forty-five minutes for the entire trip. Fail a rolling retest, or fail to provide a sample within six minutes, and the device triggers a violation reset. The horn sounds continuously until you turn off the engine.⁵ The device will not cut the engine mid-drive for safety reasons, but it will lock you out entirely if the unit is not serviced within five days of a violation reset.

Certification

Every device used in Indiana must be certified by the state Department of Toxicology. The department sets minimum standards requiring accuracy, resistance to bypass attempts, evidence of tamper attempts, and no interference with safe vehicle operation. A warning label must be affixed stating that tampering is a crime.⁶ You must use a vendor whose device carries that certification.

Getting Specialized Driving Privileges

An interlock order almost always rides along with specialized driving privileges, which is Indiana’s version of a restricted or hardship license. You have to petition the court that ordered your suspension. The petition must be verified (signed under oath), include your age, date of birth, and address, state the grounds for relief, and be served on both the BMV and the prosecuting attorney.⁷

Once granted, keep a copy of the court order in your vehicle at all times and produce it if a police officer asks. You also need to maintain proof of future financial responsibility insurance (SR-22) for the duration of your specialized driving privileges,⁷ and if you hold a CDL you cannot operate commercial vehicles during the suspension even with specialized privileges.

What It Costs

Costs vary by provider, but a one-time installation fee typically runs between $50 and $150. Monthly service averages roughly $90, and some providers quote a daily rate around $3. Those charges are yours to pay. Indiana’s interlock statute contains no financial hardship exemption. IC 9-30-8-4 makes calibration and maintenance the manufacturer’s responsibility in the sense that the manufacturer must ensure the device stays accurate; you still pay the service fees.⁸

Service appointments run monthly. At each visit the provider downloads the device’s data log, recalibrates the unit, and generates reports that go to the court or your probation department. Every startup test, rolling retest, failed attempt, and any evidence of tampering shows up in those reports. Miss an appointment and the device can lock out, leaving your vehicle undrivable until you get in for service.

Penalties for Violations

Indiana has several overlapping statutes covering different types of interlock violations, and the penalties are not identical.

Violating the Court Order

If a court ordered you to drive only with an interlock and you breach that order, whether by driving another vehicle without one, failing to install the device, or any other violation, you face a Class A misdemeanor. That carries up to one year in jail and a fine of up to $5,000.¹⁹ This is the most serious interlock-specific charge.

Tampering

Tampering with the device to circumvent it or make it inaccurate is a separate offense under IC 9-30-5-8, classified as a Class B misdemeanor, which carries up to 180 days in jail. Asking someone else to blow into the device or start the vehicle for you is a Class C infraction, a fine-only offense.¹⁰ The same conduct can also be charged as violating the court order under IC 9-30-5-16(c), which puts the Class A misdemeanor penalties back on the table.

Driving Without the Required Device

If you are required to have an interlock and operate a vehicle without one, the charge depends on your mental state. Doing so unknowingly is a Class B infraction. Doing so knowing you are required to have the device is a Class B misdemeanor with potential jail time.¹¹

Probation Consequences

Any interlock violation can also be treated as a probation violation if the interlock was a condition of probation, which gives the court authority to revoke probation and impose the original sentence. Courts also routinely extend the interlock period, add alcohol treatment, or tighten the conditions of your specialized driving privileges.

Defending a Reported Violation

A failed breath test does not necessarily mean you were drinking. Mouthwash, certain medications, and some foods can trigger a positive reading at the 0.02 threshold. The device timestamps every test, so a single failed startup followed by a clean retest a few minutes later is usually treated differently from a pattern of failures. Your service provider’s reports are the central evidence.

Device malfunction is a legitimate defense. Improper calibration or a technical fault can produce unreliable data, and Indiana places calibration and maintenance responsibility on the manufacturer.⁸ Service records documenting the malfunction carry real weight in court.

Insurance

The OWI conviction, not the interlock itself, drives your insurance costs up. Indiana insurers classify risk based on factors with a probable effect on losses, and a drunk driving conviction is one of the biggest. Expect premiums to increase substantially, often doubling or more. On top of higher rates, Indiana requires you to file an SR-22 as proof of future financial responsibility. Your insurer files it electronically with the BMV, and you have to maintain it for at least 180 consecutive days without a lapse.¹² If SR-22 coverage lapses even briefly, the BMV is notified and your driving privileges can be suspended again.

Employment

If your job involves driving, the interlock creates real problems. Employers are not required to accommodate the device on company vehicles, and the statute specifically contemplates labor agreements that bar convicted employees from operating the employer’s fleet.¹ In that situation, the court cannot order the interlock installed on the employer’s vehicle, which means you simply cannot drive for work if the job requires a company vehicle.

For jobs that use personal vehicles, the device does not stop the car from operating normally once you pass the breath test. The friction is time: regular shop visits for service, and failed rolling retests or lockouts that can strand you during work hours.

Out-of-State Travel

Driving across state lines with an interlock is generally possible, but it is not guaranteed. Your court order may include geographic restrictions, so review it before planning any out-of-state travel or check with your probation officer. Even if Indiana lets you go, the destination state may not recognize your restricted driving privileges. States share information through the Driver License Compact, but the compact does not automatically make one state’s restricted license valid in another. You could be legally permitted to leave Indiana and still unable to lawfully drive once you cross the border. If you need to travel regularly for work, you can petition the court to modify travel restrictions, but you will need to show the travel is necessary and that you can maintain compliance while away.

1
Indiana General Assembly. Indiana Code 9-30-5-16 – Specialized Driving Privileges; Ignition Interlock Device; Violation
2
Indiana General Assembly. Indiana Code 9-30-5-3
3
National Conference of State Legislatures. State Ignition Interlock Laws
4
Justia. Indiana Code 9-30-8-2 – Blood Alcohol Level Rendering Vehicle Inoperable
5
Indiana General Assembly. Title 260, Article 3 – Ignition Interlock Devices
6
Indiana General Assembly. Indiana Code 9-30-8-3 – Standards and Specifications; Approval of Ignition Interlock Devices
7
Indiana General Assembly. Indiana Code 9-30-16-3 – Stay of Suspension; Specialized Driving Privileges
8
Justia. Indiana Code 9-30-8-4 – Calibration and Maintenance; Responsibility
9
Indiana General Assembly. Indiana Code 35-50-3-2 – Class A Misdemeanor
10
Indiana General Assembly. Indiana Code 9-30-5-8 – Ignition Interlock Device Offenses
11
Indiana General Assembly. Indiana Code 9-30-6-8 – Probable Cause; Suspension of Driving Privileges
12
Indiana BMV. Proof of Financial Responsibility