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What Does an Alcohol Warning Mean on an Ignition Interlock?

Quick answer

We found no statute that defines a separate "alcohol warning" on an ignition interlock. The Virginia Code sets the interlock limit at 0.02 percent and describes a horn-and-lights alert when a driver fails or skips a rolling retest. What a warning means for your record depends on your state and the device provider, so read your program paperwork.

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In this article
  1. What the law we read says
  2. Alerts while driving
  3. Records
  4. What we could not confirm

What the law we read says

Virginia Code 18.2-270.1 defines an ignition interlock system as a device that prevents a motor vehicle ignition from starting if the driver’s blood alcohol content exceeds 0.02 percent. It also defines a rolling retest: a breath test required at random intervals while the vehicle is being driven.

Alerts while driving

If the driver fails a rolling retest or does not take it, the statute says the device sounds the horn and flashes the lights. The statute does not describe any other kind of warning or say how long such an alert stays on the record.

Records

Devices must log the breath alcohol reading at ignition, at attempted ignition and at rolling retests. Offenders must give their program quarterly printouts of these logs.

What we could not confirm

We found no official page that defines the word “warning” on the device screen. Devices, readings and penalties differ by state and by provider. A warning may or may not count as a violation in your program, so ask the agency or provider that monitors your device, or a lawyer.

A breath reading is not a legal BAC result. Do not drive after drinking. To see how much alcohol is in your drinks, use the standard drink calculator.

People also ask

What blood alcohol level stops an interlock from starting a car?

In Virginia's statute the limit is above 0.02 percent. Other states set their own limits.

What is a rolling retest?

A breath test required at random intervals while the vehicle is being driven. A failed or missed test sounds the horn and flashes the lights in Virginia.

Does an interlock warning count as a violation?

We found no official definition of a warning. Ask your state agency or device provider.

General information only, not medical or legal advice. If you have a health condition, take medicines or are pregnant, ask your doctor before drinking alcohol. Never drink and drive.

Sources

  1. Virginia Law Information System: Code of Virginia 18.2-270.1, read 4 Nov 2026
Written by A to Z Alcohol Editorial Team · Published Jun 19, 2026 · Updated Nov 4, 2026
About · How we verify this · Editorial policy · Corrections

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