Maryland Ignition Interlock Program: Requirements, Costs, and Duration

The Maryland ignition interlock program requires drivers with certain DUI or DWI outcomes, and drivers who choose it in place of a license suspension, to install a camera-enabled breath-testing device on every vehicle they drive. The device reads your breath alcohol concentration before ignition and blocks the vehicle from starting if the reading is above 0.025 BAC. As of October 1, 2024, the program reaches more offenses than it once did, and first-time offenders with a BAC as low as 0.08 can be enrolled.¹

Who Has to Enroll

Since October 2024, Maryland requires interlock participation for anyone who receives a conviction or probation before judgment for DUI, DWI, refusing a breath test at the time of arrest, or causing a fatal or life-threatening injury while driving under the influence.¹ The program is no longer limited to high-BAC or repeat offenders. A first-time DWI at 0.09 triggers the same requirement as more serious cases; the severity of the offense affects how long you stay in the program, not whether you enter.

The Elective Route

If your license is suspended after an alcohol-related traffic stop, you can elect the interlock program instead of requesting a hearing or waiting out the suspension. This keeps you driving on a restricted license during a period when you would otherwise be off the road. The election form is on the back of the Order of Suspension the MVA sends you.¹

Elective enrollment lengths depend on the stop:

BAC of 0.08 to 0.14: 180 days
BAC of 0.15 or higher: one year
Breath test refusal: one year

How the Device Works

Maryland’s interlock devices are camera-equipped. Each time someone blows into the mouthpiece, the device photographs them, which is how the state keeps another person from providing your sample. A reading above 0.025 BAC prevents the vehicle from starting.¹ That threshold sits well below the legal driving limit, so even a small amount of alcohol can lock you out.

The device keeps checking after you’re on the road. It prompts random rolling retests while you drive, and you have to provide a sample when it asks. You don’t need to pull over, but you do need to blow. A missed retest counts the same as a failed one and shows up on your monthly report.¹ If you leave the car running while you step away, you won’t hear the alert and you’ll register a violation. Turn the vehicle off whenever you aren’t driving it.

If you are deaf or hard of hearing, the device can be fitted with external LED lights that flash to signal a retest in place of the standard beep.¹

Everything the device records goes into a data logger: date, time, BAC readings, any attempt to disable or modify the unit, and whether you completed each rolling retest. Your service provider downloads this data at your monthly appointment and sends a report to the MVA.² Anything unusual gets flagged for review.

Getting Enrolled and Serviced

If a court orders you into the program, or you choose to participate after a suspension, the process runs through the MVA. Elective participants complete the election form on the back of the Order of Suspension. Once enrolled, you pick a state-approved service provider from the MVA’s list, schedule installation, and bring the vehicle in.¹

After installation you return to the provider roughly every 30 days for calibration, data download, and general maintenance. Skipping a service appointment is treated as a program violation, so treat those visits as fixed obligations.

What It Costs

You pay for installation, monthly monitoring and calibration, and eventual removal. Providers set their own rates, which is why costs vary and why it pays to call more than one before you commit.²

If you receive food assistance or other qualifying public benefits, Maryland requires providers to offer the interlock at 50% of their normal rental rate. The MVA also has an application to waive interlock fees entirely for eligible participants.¹ Check whether you qualify before assuming you can’t afford the program.

How Long You Stay In

Program length depends on the offense and how you got there. For conviction-based enrollment, the minimums are:

First conviction: 6 months
Second conviction: 12 months
Third conviction: 18 months

Elective participants stay in for 180 days if their BAC was between 0.08 and 0.14, and one year if it was 0.15 or higher or if they refused the breath test.¹

Violations can extend those periods. The MVA looks at your compliance record before authorizing removal, so a run of failed retests or missed appointments near the end of your enrollment can push your exit date back. Successful completion depends on a clean record in the final stretch.

Violations and Tampering

The MVA tracks failed startup tests, missed or failed rolling retests, skipped service appointments, and attempts to start the vehicle without taking the test.¹ Any of those can lengthen your enrollment or draw further MVA action.

Tampering with the device or trying to bypass it is a criminal offense in Maryland. A conviction carries up to two months in jail, a fine of up to $500, or both.⁴ Tampering can also cost you the restricted license and reinstate the full original suspension. Because the camera and data logger record every attempt, providers pick up on anomalies during the monthly download.

Asking someone else to blow for you falls under the same statute. The camera captures a photo during every test, and mismatched images get reported.

Getting the Device Off

When your enrollment period ends and your compliance record is clean, the MVA authorizes removal, and you return to your service provider to have the device taken off. Don’t remove it yourself or use anyone who isn’t an approved provider; the MVA needs confirmation from the approved provider that removal happened properly. Once that’s on file, the MVA issues the documentation that restores your full driving privileges. For court-ordered participants, early removal before the court’s period expires generally isn’t possible unless the underlying case outcome changes.

If You Hold a CDL

Federal regulations prohibit employers from letting a driver operate a commercial motor vehicle in violation of any license restriction.⁵ Most commercial vehicles aren’t equipped with interlock devices, so an interlock restriction effectively keeps you out of the driver’s seat commercially for the length of the program. If your income depends on a CDL, this is where a Maryland DUI outcome will hit hardest.

Moving or Driving Out of State

Maryland’s interlock requirement follows you. Under the Interstate Driver License Compact, member states share information about license restrictions. If you relocate and apply for a license in your new state, the National Driver Register will flag the Maryland interlock restriction, and the new state will require you to finish Maryland’s requirements before it issues an unrestricted license. Driving across state lines on a trip doesn’t change anything either; the device stays on your vehicle no matter where you drive it.

Insurance and Employment

A DUI conviction and interlock enrollment typically raise your auto insurance premiums, with rate increases of 50% or more common. Maryland may also require you to file an SR-22 certificate of insurance after a DUI-related suspension, which is a form your insurer submits to the state confirming you carry at least the minimum required coverage. Not every insurer offers SR-22 filings, so you may need to shop.

The employment picture depends on what your job involves. Roles in transportation, delivery, or sales often require you to disclose license restrictions. The restricted license does allow you to drive for work as long as the interlock is installed in the vehicle you’re operating. If your employer’s vehicle doesn’t have one and the employer won’t install one, you may face reassignment. Outside of driving-dependent work, employers generally won’t know about your interlock participation unless you tell them or a background check surfaces the underlying DUI.

1
Maryland Department of Transportation Motor Vehicle Administration. Maryland Ignition Interlock Program Rules and Requirements
2
Maryland MVA. Maryland Ignition Interlock Program
3
National Conference of State Legislatures. State Ignition Interlock Laws
4
Maryland General Assembly. Maryland Transportation Code 21-902.2 – Ignition Interlock System
5
eCFR. Part 383 Commercial Driver’s License Standards; Requirements and Penalties