When Is an IID Required for a California DUI?

 Posted on August 14, 2025 in DUI

In the state of California, having an ignition interlock device (IID) following a DUI conviction may be much more than an inconvenience – it can be a mandated requirement to keep your driving privileges. An IID is a device installed on your vehicle that tests your breath, preventing you from starting the car if alcohol is detected on your breath.

IIDs were once required only for repeat offenders, but California has expanded IID laws significantly to the point that some first-time DUI convictions will come with an IID requirement. An IID requirement may come from a judge as part of sentencing for a DUI conviction, or it can come from the California DMV. If you have questions regarding an IID mandate or need a solid defense for your DUI charges, speak to an experienced Sonoma, CA DUI lawyer.

What is an Ignition Interlock Device?

A California IID is a breathalyzer installed in a vehicle that prevents the engine from starting if alcohol is detected on the driver’s breath. The device also requires periodic, random breath samples while driving to ensure continued sobriety and prevent others from performing the initial breath test for an inebriated driver. The device is connected to the vehicle’s ignition system by an approved installer.

If the device detects alcohol above a certain threshold (0.029 percent), the engine will not start.  The IID records the driver’s BAC level at each test, also recording when the vehicle starts and stops, any failed tests, and any other anomalies. Some devices even record the location and mileage of the vehicle for those with restricted licenses. Failing a breath test or attempting to circumvent the IID in any way can result in additional penalties, including a license suspension.

When Might a Driver Be Ordered to Have an IID Installed?

As noted, an IID can be court-ordered as part of a DUI sentence, or can be DMV-ordered following an administrative per se hearing. In certain cases, an IID can even be required for a DUI case reduced to a "wet reckless." IID installation is required in California in the following circumstances:

• A first-time DUI with injury requires IID installation for six months.
• A first-time DUI without injury has an option for IID installation for six months, as the IID can replace a license suspension. (The alternative is a one-year restricted license with no IID)
• A second DUI always requires an IID for 1 year, regardless of the type of DUI.
• A third DUI triggers mandatory IID installation for two years.
• A fourth or subsequent DUI results in mandatory IID installation for three years.
• If a driver refuses to submit to chemical testing, the option of an IID is not allowed, and the driver’s license will be suspended.  

Are There IID Exemptions?

Drivers whose offense occurred or occurs between January 1, 2019 and January 1, 2026, may be eligible for an exemption. However, if an exemption is granted, the driver must serve the full suspension or revocation term. If the driver does not own a vehicle, has no access to a vehicle where he or she lives, and no longer has access to the vehicle driven at the time of the DUI, an exemption can be requested.  

An out-of-state driver who has completed a California DUI treatment program and has not completed the mandatory IID restriction period could be eligible for an exemption (out-of-state residency must be proven). The third type of exemption is a medical exemption for those with a medical condition that prevents breathing into the device with sufficient strength to activate it.

Contact a San Francisco, CA DUI Lawyer

An IID requirement can affect your daily life, your finances, and your job, but with a solid strategy, you may be able to minimize how long the IID is necessary, or even avoid it entirely. An experienced Napa, CA DUI attorney from Burglin Law Offices, P.C. can challenge the evidence, represent you at DMV hearings, and negotiate the best possible outcome.

Attorney Burglin has represented more than 5,000 clients charged with DUI. He is a graduate of the University of Indiana’s comprehensive course on chemical testing and scientific protocols in DUI cases. To schedule your free consultation, call 415-729-7300 today.