Driver Services

Ignition Interlock

Certified Ignition Interlock Program

When Arizona law mandates use of an interlock following a period of driver license suspension/revocation, you must have one installed by an MVD-authorized company and provide proof of the installation.

MVD uses special forms and procedures to monitor drivers required to have the device installed. You may be issued a replacement driver license containing the words "Ignition Interlock" and mark your record so that law-enforcement officers will be aware of the interlock requirement if you are stopped.

How It Works

An ignition interlock is a breath-analyzing device slightly larger than a cell phone and is wired to the vehicle's ignition and installed on the vehicle dashboard. Before the vehicle can be started, the driver first must exhale into the device. If the interlock detects alcohol on the breath, the engine will not start.

At random times after the engine has been started, the device will require the driver to provide another breath sample. If the breath sample isn't provided, or the sample exceeds a set blood alcohol level, the device will log the event, warn the driver and then start up an alarm (e.g., lights flashing) until the ignition is turned off, or a clean breath sample has been provided.

For safety reasons, the device cannot turn off the car ignition once it has been started.

Interlocks Help to Prevent Drunk Driving

The International Council on Alcohol, Drugs and Traffic Safety maintains that interlocks, when combined with a comprehensive monitoring and service program, lead to a 40-95 percent reduction in the rate of repeat drunk driving offenses among offenders as long as the device remains on the vehicle.