What You Need to Know About Ignition Interlock Devices (September 2026)

After a first DUI arrest, the license paperwork and the court case raise the same question: will you need an ignition interlock device, and for how long? The answer isn't the same in every state, or even in every case within the same state.

That's because two separate processes run after an arrest. The DMV side handles your license through an administrative process. The criminal court handles the case itself, on its own timeline. An interlock requirement can come from either track, neither, or both, depending on where the offense happened and the facts of the case.

This guide covers what an ignition interlock device is, where interlock laws stand as of September 2026, and the general shape of what happens after a first DUI. It's general information about how the process works, not legal advice or a substitute for guidance on your specific case.

What an ignition interlock device actually is

An ignition interlock device (IID) is a small breathalyzer wired into a vehicle's ignition. The car will not start until the driver gives a breath sample below a set alcohol threshold.

Once the engine is running, the device asks for occasional retests, called rolling retests, to check that the driver's breath alcohol level is still under that threshold. Test results and events are recorded on the device and reported to the monitoring authority that ordered it, usually a state licensing agency or a court, on the schedule that authority requires. That record is one input the monitoring authority uses to assess compliance, not a stand-alone verdict on it.

Where ignition interlock requirements stand as of September 2026

Ignition interlock laws vary by state, and by the specific point in the process where the requirement attaches. Most states now require an interlock in some DUI cases, but the trigger differs: a conviction alone, a high BAC reading, an injury, a judge's order, or a repeat offense.

States commonly described as "all-offender" require an interlock for every DUI conviction, including a first offense. But that label describes the criminal conviction trigger. It doesn't necessarily tell you whether an interlock also applies during the administrative license suspension that happens before a case is resolved, or as a condition of reinstating a license afterward. Those can be governed by separate rules within the same state.

California runs its ignition interlock rules under a statewide pilot program. The program stays in place through January 1, 2033.

Repeat offenders and cases involving injury face longer IID periods, from one to four years depending on prior convictions, according to California DMV materials. A first offense works differently. It depends on three separate pieces: the administrative license action, the conviction itself, and any order the court adds. Each one is evaluated on its own.

Because the applicable rule depends on where the offense happened and which track (administrative or criminal) is driving the requirement, the reliable move is to check your own state directly. The IIHS, a nonprofit highway research organization, keeps a current, state-by-state summary of alcohol interlock laws you can use as a starting point.

What to expect after a first DUI, step by step

After a first DUI, two separate processes run at the same time, and an interlock requirement can come from either one. One track is administrative, handled by the state licensing agency. The other is criminal, handled by the court.

Here is the general order of events. Timeframes, deadlines, and requirements vary by state, so treat this as the typical shape rather than a fixed script.

1. Arrest and immediate license action. Many states suspend or restrict the license right away and issue a temporary permit so the driver can keep driving while the case moves forward.
2. The administrative hearing. Drivers who want to challenge the suspension typically have a limited window to request a hearing with the licensing agency, and that window is set by state law.
3. The court case. The criminal side moves on its own timeline, from the first court date through the final resolution.
4. The interlock requirement. An IID can be ordered by the licensing agency, the court, or both, depending on the state and the case.
5. Installation and monitoring. Once the device is installed, the monitoring period runs. Removing the device typically requires formal clearance from whichever authority ordered it, not just reaching the end of the calendar period.

The exact rules for a first offense depend on your state. In California, for example, whether an interlock is required at all turns on the details of the case. You can read the full breakdown in the guide to California's first-DUI IID requirements.

Will a first DUI require an ignition interlock device?

It depends on the state and the facts of the offense. In states with all-offender laws, a first conviction requires an interlock. In others, the requirement is triggered only by a high BAC reading, an injury, or a judge's order.

A number of factors decide the outcome: your state's law, your BAC at the time, whether anyone was injured, prior convictions, whether you refused a chemical test, your age, any probation terms, and whether the vehicle itself is exempt or covered under your state's rules. And the source of the requirement matters too, since it can come from the licensing agency, the court, or both.

"All-offender" is also not one fixed thing. The label usually describes the conviction requirement, meaning an interlock is mandatory once someone is convicted. It doesn't automatically tell you whether an interlock also applies earlier, during an administrative license suspension before the case is resolved, or later, as a condition the DMV attaches when reinstating a license. Those can be governed separately, even within an all-offender state.

California illustrates how these pieces fit together rather than sitting under one rule. The administrative license action and the court-ordered condition come from different parts of the Vehicle Code. Which one applies, and for how long, depends on a few things:

• Whether there's a prior conviction
• Whether anyone was injured
• Whether the driver is going through the DMV's restricted-license process, the court's probation process, or both

For a first offense without injury, published guidance commonly puts the IID period in the five-to-six-month range, though whether it is mandatory or optional depends on which of those processes is driving the requirement in a given case. The specifics, including how the DMV and court processes fit together, are covered in the guide to what California requires after a DUI. 

What living with an interlock is actually like

Once installed, an interlock becomes part of the daily driving routine. You give a breath test before the car will start, respond to rolling retests while driving, and bring the vehicle in for scheduled calibration visits where a technician downloads the device's logs and checks the sensor.

Calibration visits happen on a schedule set by the state and provider. California requires calibration at intervals not exceeding 60 days. Missing one can count against you.

A handful of things can lead to a violation: a failed breath test, a missed or failed rolling retest, a missed calibration appointment, tampering with or bypassing the device, or driving an unequipped vehicle when one is required. Whether a specific incident counts as a violation, and what happens next, depends on the program and the circumstances. Events are recorded and reported to the monitoring authority, which reviews them. See the dedicated violations guide for the full list and how to avoid one.

Day to day, the device is manageable once the routine sets in. Cold mornings can slow a reading, and you plan trips knowing a retest may be prompted while you drive, but neither stops you from getting where you're headed.

What to know about BACtrack Drive

BACtrack Drive is a California DMV certified ignition interlock service for drivers meeting an interlock requirement in a covered California area. It is a California program, not a national one, so it fits readers whose case falls in its service region.

The service runs a flat $99 per month covering monthly service, installation, and calibration visits; removal is quoted separately. BACtrack Drive's network spans service centers in 24 California cities, from the Bay Area and Sacramento to Southern California.

For drivers who qualify, it also checks eligibility for California's income-based discount and handles the application.

See if BACtrack Drive covers your install at drive.bactrack.com.

Frequently Asked Questions

References

1. IIHS. "Alcohol interlock laws by state."
2. California Department of Motor Vehicles. "Statewide Ignition Interlock Device Pilot Program."
3. California Legislative Information. "Assembly Bill 366 (2025-2026), Ignition Interlock Devices."
4. California Legislative Information. "Vehicle Code 23575."