Indiana OWI Ignition Interlock: Requirements, Cost, and What to Expect

The ignition interlock device — a breathalyzer wired into your car's starter — isn't an automatic requirement for every first-offense OWI in Indiana. But it shows up far more often than the statutes might suggest, because judges have broad discretion to order one as a condition of Specialized Driving Privileges. Here's when to expect it, what it costs, and what the compliance rules look like.

When an IID Is Required

Discretionary (most first offenses): For a standard first-offense OWI with a BAC below 0.15%, Indiana criminal statutes don't mandate an IID. However, judges frequently order one as a condition of granting Specialized Driving Privileges — especially when the BAC was close to the 0.15% threshold or there are other aggravating factors.

Effectively mandatory (high BAC): For a Class A misdemeanor OWI (BAC 0.15% or higher), courts almost universally require an IID as a condition of any driving privileges. The heightened judicial scrutiny for high-BAC cases makes approval without an IID unlikely.

Legally required (chemical test refusal): If you refused the breath, blood, or urine test, standard SDP is unavailable. The only path to driving privileges during a refusal suspension is through IC § 9-30-6-8(d), which requires an IID for the entire duration. No IID, no driving.

How the Device Works

The IID is installed in your vehicle by a state-certified vendor. Before starting the car, you blow into the device. If your breath sample registers above the preset threshold (typically 0.02% BAC), the car won't start.

The device also requires periodic "rolling retests" while driving — you'll be prompted to provide a breath sample at random intervals. A failed rolling retest doesn't shut off the engine (for safety), but it triggers an alarm sequence (horn, lights) and logs the event for the court.

Every data point — start-up tests, rolling retests, failed attempts, skipped tests — is recorded in the device's memory and downloaded during monthly calibration appointments.

The Costs

IID expenses are entirely on the driver:

• Installation: $100–$150 (one-time)
• Monthly lease and calibration: $70–$100 per month
• Daily equivalent: approximately $3 per day
• Total for a six-month period: $500–$800
• Removal fee: typically $50–$100

The monthly calibration appointment isn't optional — the certified vendor must service and recalibrate the device on a set schedule. Missing a calibration appointment is a compliance violation reported to the court.

Installation and Compliance Timeline

Within 72 hours of the court order: You must have the IID installed by a certified vendor and submit a Certificate of Installation to the court. This deadline is strict — failure to provide proof of installation can result in revocation of your driving privileges.

Monthly: Report to the certified vendor for calibration and data download. The vendor reports the results to the court and your probation officer.

Duration: The IID remains installed for the period specified in the court's SDP order. For refusal cases, it stays in until the underlying criminal charges are resolved. For court-ordered installations as a condition of SDP, the duration matches the SDP period.

Choosing a Vendor

Not every interlock installer is approved for use in Indiana. The BMV maintains an approved provider registry, and the list is updated quarterly. Before paying any installation deposit, verify that the vendor appears on the current BMV-approved list. Completing your IID requirement through a non-certified provider means the court won't credit the time served.

Consequences of Tampering or Violations

Tampering with, circumventing, or having another person blow into the IID is a Class B misdemeanor under Indiana law, carrying up to 180 days in jail and a $1,000 fine. Common violations include:

• Having someone else provide the breath sample
• Attempting to disconnect or bypass the device
• Failing to appear for calibration appointments
• Repeated failed start-up attempts suggesting attempted impaired driving

The court reviews IID data reports and can revoke SDP, impose additional penalties, or issue a bench warrant for any violation.

IID Credit Toward Final Suspension

One practical benefit of the IID: under IC § 9-30-16-1(e), the period of IID installation can be credited toward any final court-ordered suspension. If the judge eventually imposes a six-month judicial suspension and you've already had the IID installed for four months, those four months count.

For refusal cases under the IID exception, the BMV will not note an administrative suspension on the driving record while the court's IID order is in effect — and the installation period counts as credit toward the final suspension.

The Indiana First-Offense DUI Guide includes the IID compliance checklist, approved vendor verification steps, and the timeline for integrating IID installation with the SDP petition process.

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