It is the constant companion of certain Arizona drivers. It is the ignition interlock device. Those drivers who have been convicted of driving under the influence are required to have the device installed in their vehicle – at their expense.

The ignition interlock device – also known as the IID – connects to the ignition of your vehicle. Before you can start your vehicle and drive, you must blow into the device, which then tests your breath.

The Arizona Department of Transportation says on its website that “If the interlock detects alcohol on the breath, the engine will not start.” The IID’s work doesn’t stop there, however.

The device will periodically require the driver to provide breath samples while you’re driving to verify the continued absence of alcohol. The IID also tracks your activity and supplies a record of any violations to the Department of Transportation.

That might sound simple and straightforward, but those who have had the devices installed in their vehicles say that IIDs can give false positives. That is, the device might indicate that a completely sober person has alcohol in his or her breath.

A false positive will trigger a report to ADOT and lead to legal problems that can include revocation of your driver’s license. Each violation extends your interlock penalty for a full year.

So what do you do after receiving notice from Motor Vehicle Services that your IID registered a violation? Immediately contact an attorney experienced in contesting the alleged infraction. You have just 15 days to request a hearing, so time is critical.

Delays can result in loss of your license or an extension of the IID penalty period.