Ignition Interlock Devices: How They Impact DUI Offenders
May 13, 2025
Driving under the influence (DUI) is a serious offense in California, and for those convicted of it, there are often significant consequences. One of the most common consequences for DUI offenders, especially those with a history of driving under the influence, is the installation of an ignition interlock device (IID) in their vehicle.
As a DUI attorney in Santa Cruz, California, I’ve seen firsthand how these devices impact my clients and their daily lives. If you're facing a DUI charge or have already been convicted, understanding how an ignition interlock device works and what it means for you is crucial. Let the Law Offices of Andrew C. Janecki help you.
What Is an Ignition Interlock Device (IID)?
An ignition interlock device (IID) is a breathalyzer installed in a vehicle that prevents the car from starting if the driver’s blood alcohol concentration (BAC) exceeds a predetermined limit. Typically, the limit is set at 0.02%, much lower than the standard legal limit of 0.08% for DUI offenses.
The device requires the driver to blow into it before starting the car. If the test detects alcohol on the driver's breath that exceeds the limit, the vehicle will not start. The IID also requires periodic retests during driving to make sure the driver remains sober. If the driver fails the retest, the car will alert them, and they may be required to pull over safely.
For DUI offenders, these devices can be a frustrating but essential part of the terms of their conviction, especially for repeat offenders or those whose DUI led to serious consequences, such as injuries or fatalities.
Who Needs an Ignition Interlock Device?
Under California law, certain DUI offenders are required to install an IID as part of their sentence. If you’ve been convicted of DUI, you may be required to have an IID installed in your vehicle, especially if you fall into one of the following categories:
First-time offenders: If your BAC was 0.15% or higher at the time of your arrest, you may be required to install an IID for a set period. In California, this period is usually between 4 to 6 months, but it can vary based on your case and the county in which you were convicted.
Repeat offenders: If you’ve been convicted of DUI previously, you may face a longer IID installation period, sometimes up to 2 years. Repeat offenders are more likely to face stricter monitoring as part of their sentence.
Offenders involved in accidents: If your DUI led to an accident with injury or death, the court may require you to install an IID in order to drive again.
Underage DUI offenders: For those under 21, California law can mandate the installation of an IID even for a first offense, especially if their BAC was above 0.01%.
In Santa Cruz, Palo Alto, San Jose, San Francisco, and Berkeley, the enforcement of these requirements can vary, but the installation of an IID is common for DUI convictions, especially in cases where the offender has a history of impaired driving.
The Process of Installing an Ignition Interlock Device
Installing an IID isn’t a simple task—it involves both time and money. The installation process typically includes the following steps:
Choose an approved IID provider: Not all vendors can install IIDs. In California, the device must be installed by a provider approved by the California Department of Motor Vehicles (DMV). There are a number of approved companies in the areas we serve, including Santa Cruz, Palo Alto, San Jose, San Francisco, and Berkeley.
Schedule installation: Once you’ve selected a provider, you’ll need to schedule an appointment for the device to be installed in your vehicle. The installation process typically takes 1 to 2 hours.
Device calibration and setup: The IID will be calibrated to detect alcohol on your breath. The provider will also set up the device to meet the specific requirements of your case.
Ongoing monitoring and maintenance: After installation, you’ll need to periodically visit the provider for device calibration and maintenance. These check-ins usually happen once a month, and the provider will report the data to the court. Any failed tests or tampering with the device can result in legal consequences, including additional penalties.
How IIDs Impact DUI Offenders' Daily Lives
Having an ignition interlock device installed can have a significant impact on your daily routine. Here’s how:
Cost of installation and maintenance: The cost of an IID isn’t negligible. In California, offenders must pay for the installation, regular maintenance, and calibration of the device, which can total between $70 and $150 per month. If you're already dealing with the financial burden of DUI fines, legal fees, and possibly losing your job due to the conviction, this additional expense can be overwhelming.
Inconvenience: An IID requires you to blow into it before starting the car and at random intervals while driving. If you fail the test, your car could stop running, which could leave you stranded, causing delays in your daily schedule.
Stigma: There’s a stigma associated with having an IID in your vehicle. For many drivers, it can feel like a constant reminder of a mistake they made, which can be embarrassing, especially when you have to explain the device to others.
Restricted driving privileges: While the IID allows you to drive, you may face restrictions in other areas of your life. For example, you may be limited to driving certain vehicles, such as your own, or only during certain hours. This could impact your ability to work, take care of family responsibilities, or engage in social activities.
What Happens if You Fail a Breath Test?
If you fail a breath test, your vehicle will not start. However, failing a test while driving the car isn’t as simple as not being able to start it. The IID will alert you that you need to pull over and provide another breath sample. If you fail this retest, it may result in consequences such as a violation of your probation, fines, or extended IID installation.
Repeated failures of breath tests can lead to further legal consequences, including the revocation of your driving privileges.
How a DUI Attorney Can Help You with IIDs
As a DUI attorney in Santa Cruz, I’ve helped many clients manage the process of DUI convictions, including the installation of ignition interlock devices. While an IID may seem like a harsh punishment, there are ways a DUI lawyer can help you through the process:
Negotiating reduced IID requirements: In some cases, a lawyer can help negotiate reduced terms for IID installation. For instance, if you’re a first-time offender or your BAC was not excessively high, there may be room for negotiating a reduced period of installation.
Challenging the need for an IID: In certain situations, a DUI attorney may be able to help you challenge the requirement of installing an IID. Depending on the circumstances of your case, your attorney may be able to argue that the device is not necessary.
Assistance with compliance: If you’ve already been required to install an IID, your attorney can provide guidance on how to comply with the requirements. They can explain the steps you need to take, help you stay on top of maintenance, and make sure you're aware of all deadlines.
Appealing IID violations: If you’ve been accused of violating the terms of your IID requirement, such as failing a test or tampering with the device, a DUI attorney can help you defend yourself.
Seeking Help From a DUI Attorney
If you're facing DUI charges or have already been convicted and ordered to install an ignition interlock device, a skilled DUI attorney can help you. If you’re in Santa Cruz, Palo Alto, San Jose, San Francisco, or Berkeley and need help with your DUI case, reach out to my office. The Law Offices of Andrew C. Janecki is here to guide you through the process, protect your rights, and work to minimize the consequences.