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Ignition Interlock Device

Man in car blowing into breathalyzer.jpg

An ignition interlock device, known as an IID, is a breath machine that is installed in a vehicle and prevents the car from operating until an alcohol-free sample is provided.

How does an IID work?

The IID is wired directly into the car’s ignition and controls for the vehicle. The device is designed to be tamper-proof. Prior to starting the vehicle, the device will require you to provide a breath sample. If any amount of alcohol is detected, the device will lock the ignition out and it will remain locked for a period of time. After the device unlocks, you may try again.  If you provide a second sample and alcohol is detected, the lock out period will increase.


To prevent a friend or passenger from starting the car, the IID will require continued samples while driving.  The device will chime indicating it is time for another sample. This allows you a moment to stop the vehicle to safely provide a sample. Should this sample indicate any presence of alcohol, the device will turn off the lights and horn to the vehicle until you shut off the car. The device will also record the presence of alcohol on its data recorder and this information will be provided to the courts.


To further prevent another person being able to provide the samples while driving, the device has a very short cord, the device will monitor breath patterns, and some devices even have miniature cameras to record who provides the sample.  The fact is IID’s are filled with anti-tamper features. 


It is also a crime to have another person provide the samples. Vehicle Code section 23247(b) makes it a crime for the restricted driver to ask another person and 23247(c) makes it a crime to provide the sample.  A person who is convicted of this section may be sentenced up to six months in the county jail and by a fine up to $5,000.

Who must install an IID?

You will be required to install an IID depending upon whether it is your first or subsequent DUI. 


First DUI


For a first time DUI, the judge may order you to install a IID if you had a particular high BAC or you refused to submit to a chemical test.  You will be required to keep the IID in the car usually for around six months.


Second or more DUI


If you are repeat defender, the judge will order you to install an IID for a period not less than one year.  The following chart shows the length of period for the most common DUIs.  If you are a repeat offender, California DMV will require you to install an IID in order to obtain a restricted license that will allow you to drive to and from work, school, and court ordered alcohol programs. 

Where to find an IID?

In order to obtain an IID, you will have to visit an authorized dealer. Below are a list of links to different dealers that service Northern California.​

Smart Start


Draeger Interlock



Guardian Interlock

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