Ignition Interlock Device (IID) Requirements in Wisconsin

What is an Ignition Interlock Device (IID)?

An ignition interlock device (IID) – sometimes called a BAIID or “breathalyzer” – measures breath-alcohol concentration (BAC) and prevents a vehicle from starting if the sample is above the setpoint. Under 2025 Wisconsin Act 210, these devices will eventually serve as a “performance-based” monitoring system for the duration of your restriction.

Important Legislative Update

2025 Wisconsin Act 210 was signed into law on April 8, 2026, but its major provisions DO NOT take effect immediately. The law has a 12-month delayed implementation period to allow the WisDOT to build out its electronic infrastructure. The current 45-day (OWI) and 30-day (Refusal) occupational waiting periods, along with existing penalty frameworks, remain fully in effect until mid-2027. The information below outlines how your compliance will be monitored once the new law officially goes live.

Modern Wisconsin-approved units include:

• Handset + mouthpiece to submit breath samples.
• Mounted camera to verify the driver’s identity during every test.
• Cellular modem to transmit compliance data to the DOT and service providers in real-time.
• Control unit installed under the dashboard.

IIDs are leased from approved providers and must be serviced regularly. The order period is typically a minimum of 12 months, as mandated by the court.

When is an IID Required?

Wisconsin law (Wis. Stat. § 343.301) mandates an IID order for:

• All repeat OWI offenders (2nd, 3rd, 4th, etc.).
• All first-offense OWI cases where the BAC is 0.15 or higher.
• All implied-consent refusals (refusing a roadside breath, blood, or urine test).

Critical Rules for Restricted Drivers

Current Law vs. Future Act 210 Rules

The rules governing your license eligibility and enforcement depend on when your offense occurs relative to the law’s official rollout:

• Occupational License Eligibility: 
  • Under Current Law: Repeat OWI offenders face a 45-day waiting period, and Refusal cases face a 30-day waiting period before getting an occupational license. Repeat refusal cases have longer waiting periods.
  • Once Act 210 Takes Effect (2027): Traditional waiting periods are completely eliminated. Eligibility becomes immediate upon installing the IID.
• Strict Motorcycle Ban: If you are under an IID order, you are strictly prohibited from operating “Class M” vehicles (motorcycles). Because IIDs are not compatible with motorcycles, you cannot ride until your full restriction period has ended.
• All Owned Vehicles: The IID must be installed on every vehicle for which your name appears on the title or registration, unless a court grants a specific financial hardship exemption.
• The 0.02 BAC Rule: While under an IID order, you may not operate any motor vehicle with a BAC above 0.02 – even if the vehicle does not require an IID for other drivers.

Compliance-Based Extensions (The 180-Day Rule)

Once Act 210 is fully operational, your IID requirement will no longer be a fixed date on a calendar. Under this upcoming “compliance-based” model, your restriction will be automatically extended by 180 days for each violation that occurs 60 days or more after installation.

Violations that trigger a 6-month extension include:

• Failed Start: Any attempt to start the vehicle with a BAC of 0.02 or higher.
• Missed Random Tests: Failure to take a random “rolling retest” while driving.
• Tampering or Circumvention: Any attempt to bypass, disconnect, or remove the device without authorization.
• Service Lockout: Failure to bring the vehicle in for scheduled service that results in the device entering a permanent lockout mode.