An ignition interlock device (IID) is a breathalyzer built into your vehicle’s ignition system. Before the car will start, you must provide a breath sample below the programmed threshold. Wisconsin law requires IIDs in a growing range of OWI cases.
When Is an IID Required?
Wisconsin requires an IID for:
- All second and subsequent OWI offenses
- First OWI offenses where the BAC was 0.15 or higher
- First OWI offenses with a minor passenger in the vehicle
- OWI offenses involving injury
- Anyone who refused the chemical test
How Long Must You Have It?
The required duration depends on the offense: typically one year for a first offense requiring an IID, longer for subsequent offenses. The IID must be installed on every vehicle you drive — not just the one you drove during the arrest.
Cost and Logistics
You are responsible for the cost of installation, monthly monitoring fees, and removal — typically $70-150 per month total. The device requires periodic calibration appointments. Data from the device is reported to the Wisconsin DMV.
Tampering and Circumvention
Tampering with an IID, driving a vehicle without one when required, or having another person provide a breath sample are all separate criminal offenses that can result in additional charges and extended IID requirements. The devices record all activity, including failed tests and attempts to circumvent.
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Attorney Christopher Carson defends OWI cases throughout Waukesha and Milwaukee counties. Call (262) 860-8932.