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Wisconsin Ignition Interlock Device

What is an IID (Ignition Interlock Device)?

An Ignition Interlock Device, IID, is a small handheld breath testing device that requires the driver to provide a sober breath sample in order to start the vehicle's ignition.Additional random breath samples will also be required periodically while the car is in motion. Failure to provide a sample, or a breath result over a certain BAC level (typically.02) will result in the sounding of alarms that require the driver to pull over. The Ignition Interlock Device stores all information and relays it to the proper authorities. 

Why would I need an ignition interlock device and for how long?

This depends case to case, with a subsequent OWI offense in Wisconsin or even with the first, you may be required to install an Ignition Interlock Device (IID) on your car. The IID requirement periods for each offense can be found on the OWI Penalties page. 

How long must I use an ignition interlock device?

IID punishments range from 1 year to the duration of a license revocation.


What vehicles will need the ignition interlock device installed?

The IID must be installed on every vehicle the defendant owns or operates. It is illegal for an offender required to have the device to operate any vehicle that is not equipped with an IID. Judges may allow a Wisconsin OWI defendant in certain circumstances to use a car that is not equipped with an IID device so long as the Judge signs an exemption order. 


Where would I get an ignition interlock device installed?

IID's are installed at designated Ignition Interlock service centers. OWI offenders are responsible for the cost of installation as well as the monthly payments for the duration of the sentence. Attempts to tamper or circumvent the IID will result in  imposition of further penalties.


How do ignition interlock devices work?

Before a vehicle is started, a sample must be given. If the sample given contains a

measurable amount of alcohol (usually .02), the interlock device prevents the engine from starting . Once an alcohol free sample is given, the engine will started. Most interlock devices also then ask for additional alcohol free tests at random periods while the vehicle is running. So not only do you have to blow to start the car, but you also have to blow periodically to keep the car running. This is to prevent someone sober from starting the car for other drunk drivers.

How much do ignition interlock devices cost?

Ignition Interlock Devices must be purchased or rented from private companies, and usually cost anywhere from $65 to $100 or more a month. Some companies charge additional fees for installation, and often a deposit is required. Additional fees may apply to maintenance and calibration, as well as transmittal of the information to the DMV.  DUI offenders that are ordered by the court to install the device usually must pay their own interlock costs.