Ignition Interlock Device Requirements From a DUI

Ignition Interlock Device Overview

If you have pled guilty to or have otherwise been convicted of a DUI, the court may require that you install an ignition interlock device (IID) in your vehicle when your license is reinstated. The ignition interlock is a device that stops a person from being able to drive their car if they have a measurable amount of alcohol in their system. The device does this by measuring a person’s breath alcohol level to see if they are registering a level of alcohol consumption.

Pilot Program

Pursuant to a pilot program implemented by the State of California that began in 2010 and has been extended through 2018, 4 counties were selected whereby all first-time DUI offenders whose convictions occurred in those counties are required to install the device in all of their vehicles. On January 1, 2019, the program will be extended state-wide to include all California counties1.

How An IID Works

This device is installed on the vehicle dashboard and requires you to provide a breath sample before operation. If any degree of alcohol is detected, the vehicle will not start. It also requires that provide additional breath samples, typically in 5 to 15-minute intervals, and within 45-minutes after the engine started so as to preclude you from drinking while the car is in operation or the engine is still on.

Breath Test While Driving

When the device requests a breath sample while you are driving, you have 6-minutes to pull over to a safe location and blow into the device. Otherwise, the engine will shut down. While you have the IID, you have unlimited driving privileges.

Installation Requirements

If a judge or the DMV orders you to install an IID, you are required to:

  • Provide the DMV with a Department of Motor Vehicles Ordered Verification of Ignition Interlock (DL 924)
  • Pay a $45 administrative fee
  • Serve the specified suspension period (usually 30-days)
  • Provide California Insurance Proof Certificate (SR-22)
  • Pay any other installation fee
  • Have it professionally installed by a court-approved installer
  • Install an IID in every vehicle that you own (motorcycles are excepted)

Installation does not include any vehicle that is employer-owned or a vehicle that you drive for work purposes such as a van or truck.

Length of Time IID Required

All first-time offenders in these counties are required to have the device for 5-months. If an injury occurred with the DUI, the device requirement is 12-months. For repeat offenders, the following time periods are required with an enhanced time if you are convicted of a DUI with injury under California Vehicle Code § 23153, or convicted of driving on a suspended license stemming from a DUI2:

  • 2nd DUI in 10-years: 1-year, but if an injury occurred: 2-years
  • 3rd DUI in 10-years: 2-years, but if an injury occurred: 3 years
  • 4th DUI in 10-years: 3-years, but if an injury occurred: 4-years

For driving on a suspended license, you risk having the device installed for 1-3 years.

These time periods apply to every driver convicted of a subsequent DUI or license suspension violation, regardless of the county where the offense occurred.


It will cost you a minimum of $75 and up to $150 for a professional to install the IID. If you are low income, there is a program for financial assistance that can lower the cost by up to 50%. There is also a recurring fee of about $50 for each time you bring the device in for calibration. These fees apply to each vehicle that you own. The DMV has a fee of at least $55.


Counties That Require IID Installation

Not all California counties require installation of an IID for first-time DUI offenders. Currently, only these 4 counties have a mandatory installation rule pursuant to the pilot program that has been extended through 20183:

  • Alameda
  • Los Angeles
  • Sacramento
  • Tulare

All first-time offenders in these counties are required to have the device for 5-months. If an injury occurred with the DUI, the device requirement is 12-months. For repeat offenders, the following time periods are required with an enhanced time if you are convicted of a DUI with injury4, or convicted of driving on a suspended license stemming from a DUI5.

How To Find A Court Approved Installer

You can find and have a court-approved installer by going to an DMV field office and getting a list, or by calling the DMV at 1-800-777-0133. There is also a web site: https://www.dmv.ca.gov/portal/dmv/detail/vehindustry/ol/forms/ignitioninterlockdevicelist

Ignition Interlock Frequently Asked Questions

Will an IID Damage my car?

No, the device is installed into the wiring of your car so no damage will be done to it. When the device is taken out, the wiring is restored to the condition it was in before installation. If you do not have it professionally installed, then you risk having your car damaged. Do not try to remove the device yourself.

Can An IID Device Be tricked?

It is highly unlikely that you can trick an IID. The device records a particular breath pattern that cannot be imitated. Some devices have a camera that records who is providing the sample or it may ask you to inhale to prove that you are a human providing the sample. And, if you do attempt to trick it, the device records each sample. It is a crime to do anything to circumvent the operation of the device.

Can an IID device have false positives?

Yes, on rare occasions the IID can produce a false positive. For instance, a spicy food could mix with HCI (hydrogen chloride gas) in your stomach to produce a methane gas, which is a hydrocarbon that the device is designed to detect.

Also, if you chew tobacco that contains ethyl alcohol, it will be detected. Mouthwashes and mouth sprays along with energy drinks can also register on the device as they contain ethyl alcohol as well. It is best to avoid these products well within the time before you decide to drive.

If I live in a county where the IID is not mandatory but I was convicted in Los Angeles County, will the judge require me to install an IID?

Yes. The county where you live is irrelevant. If your DUI occurred in any of the 4 pilot counties, which includes Los Angeles, the judge will require you to install the device on all of your vehicles.

If I am required to have an IID, do I get one immediately after ordered to do so?

 If you received an APS (Administrative Per Se) suspension rather than from the court and are a first offender, then you must wait 30-days before being eligible for an IID.

What if I do not own a car?

If you do not own a car, then request an exemption from IID installation using Exemption for Interlock Ignition Device (DL4055B) and submit to the DMV field office or mail it to Driver Licensing Mandatory Actions Unit within 30-days of your receipt of your suspension or revocation mail date.

What happens after the 5-month installation ends for a first-time offender? Do I get my regular license back?

If a first-time offender in any of the pilot counties, have the IID removed after the 5-month period ends by a certified installer. Your IID restriction is automatically removed but you will only receive a restricted license allowing you to driver to and from work or an approved DUI or alcohol treatment program for the duration of your license suspension.

Does the Ignition Interlock Device Shut Off A Car’s Engine?

No. The ignition interlock device will make the car’s horn sound if you fail a repeat breath alcohol test. The car’s lights will usually flash until you pass the breath test or until you shut off the engine.

What Happens If I Have An Ignition Interlock Device And Fail The Breath Alcohol Test?

If you have an ignition interlock device on your car and fail the breath alcohol test, the device will enter a short lockout period for several minutes. If you fail another breath alcohol test, the lockout period will be longer. The lockout period will allow alcohol to dissolve from your mouth and give you time to decide why you failed the test.

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Hiring An Attorney

The state of California has implemented tough drunk driving laws, including the requirement of having ignition interlock devices installed on cars of repeat DUI offenders. Drivers who have been convicted of Driving under the influence in California may have worries about possible license suspensions and may also have worries about being able to drive their children to school and drive themselves to work with an ignition interlock device on their car.

At the Aizman Law Firm, our experienced DUI attorneys can help you with questions you might have overlooked about going on with a normal life while an ignition interlock device is installed on your car. Contact us at 818-351-9555 for a free confidential consultation.

Legal References

  1. SB-1046 []
  2. California Vehicle Code § 14601 []
  3. AB 91; CVC § 23700 []
  4. CVC § 23153 []
  5. CVC § 14601 []

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