An Ignition Interlock Device (“IID”), is a small Breathalyzer that can be hooked up to your car.  It is designed to prevent your vehicle from starting, unless you provide a breath sample that is alcohol free.  In some cases, required installation of an IID, will be issued as a penalty for Driving Under the Influence (IID).  This penalty is becoming more and more popular throughout California.  This article will provide you with general information about IID’s, and when you might expect to have to install one in your vehicle.  If after reading this article, you still have additional questions, we encourage you to contact one of our experienced defense attorneys at the San Diego DUI Attorney. 

Contact our office today at 619-535-7150 for your FREE DUI Consultation.

The Ignition Interlock Device

As noted above, the IID is a small breath testing device, that can be installed to your vehicle.  If you are ordered to install an IID as part of your DUI penalty, you will have to have the IID installed on each car you drive or own.  You will have to pay for the installation yourself, and have each one installed professionally.  You will also be responsible for taking it to be serviced every 60 days.    

Prior to starting your car’s ignition, you will have to provide a breath test sample that is alcohol free.  Unless you do, the car will not start.  Additionally, you will be asked to provide further samples after you begin driving, and throughout your ride.  For these additional samples, the device will give you ample time to pull your vehicle over, if necessary, and safely provide a sample.   

Failing one of these additional tests, will not shut off your car.  Alternatively, it will keep record that you failed the test, and the record will be reported to the court. 

Many people think they will just be able to have a sober friend in the vehicle blow into the device, and start the car for them.  However, the IID’s are specifically designed to prevent people from doing so.  As noted above, they require a test to start the car, and then additional tests once the car is being driven.  The cords on the IIDs are very short, making it difficult/impossible for a passenger to provide these additional samples.  Moreover, California law has made it a crime to have someone else provide the sample for you.  

In addition to recording your breath sample, the IID will also record all attempts to tamper with, or disconnect, the device, and each time the engine is started and stopped. 

Ignition Interlock Device As A Dui Penalty

Technically, installation of an IID can be issued as a penalty, at the judge’s discretion, for any DUI-related conviction.  This includes a standard DUI, DUI on a suspended license, or DUI causing injury, to name a few.  

While IID’s can be issued at the judge’s discretion, for a First Offense DUI, they will typically only be required if you refused a post-arrest breath or blood test, or you had a BAC of .15% or greater.

As discussed below, there are also situations in which installing an IID will be a required penalty. 

Ignition Interlock Device Pilot Program

Since 2010, the state of California has been running an IID “pilot program”. The program requires IID installation for First Offense DUI convictions in specified counties.  San Diego county is not currently one of the counties in the program.  The participating counties are:

  • Sacramento County;
  • Los Angeles County;
  • Tulare County; and
  • Alameda County.

If convicted for a typical DUI in any of these counties, you will be required to install an IID for a period of five (5) months.  For a DUI causing injury, the IID will have to be installed for one (1) year. 

The goal of this pilot program is obviously to reduce the amount of DUIs, and DUI related deaths and injuries.  If the program proves to be a success, it will likely become statewide law sometime within the near future. 

Ignition Interlock Device Pilot Program – Repeat Offenders

In the counties listed above, the Pilot Program also has requirements for repeat DUI offenders.  As you would imagine, the penalties for a repeat offender are more severe.  They include:

  • For a Second Offense Conviction: Required installation of an IID for one (1) year;
  • For a Third Offense Conviction: Required installation of an IID for two (2) years;
  • For a Fourth Offense Conviction: Required installation of an IID for three (3) years.

If the DUI causes injury, the IID will have to be installed for even longer.

Currently, these requirements are only applicable to the counties listed above.  Depending on the success of the program in deterring DUIs, the requirements could become statewide law in the future. 

Ignition Interlock Device – Mandatory Sentences

driving on a suspended license

If your license was suspended or revoked as the result of a DUI, and then you are convicted of driving on a suspended/revoked license, you may be ordered to install an IID.  Depending on the circumstances of the case, the judge can order the IID to be installed for a period of time between one (1) and three (3) years. 

restricted licenses

In some cases, after you are convicted of a DUI, or related offense, you may be able to obtain a “restricted license” from the DMV.  If you are granted a restricted license it will likely only permit you to driver to and from work, school, and/or a DUI education program.  In many cases where a restricted license is granted, the driver will be required to install an IID for the pendency of the restricted license. 

the cost of installing / maintaining a california ignition interlock device

The cost of installing an IID will vary slightly depending on the company that does the installation.  On average, the cost of installation will be around $100.  Keep in mind, however, that you will also have to pay to have the device serviced about every 60 days.  In total, you will likely end up paying about $2.50 for each day the IID is installed. 

In some cases, under the pilot program, if you are required to have an IID installed, but you can not afford to do so, you will only have to pay for a portion of the installation and maintenance costs. 

finding an ignition interlock device installer

As noted above, if you are required to install an IID, you will have to have it installed by a court-approved installer.  There are a number of companies that have multiple locations, and have been court-approved.  Some of these include:

  • Sens-O-Lock;
  • Intoxalock;
  • Smart Start of California;
  • Alcohol Detection Systems; and
  • Guardian Interlock.

For more information on these companies, visit their websites. 

ignition interlock device – accuracy

If you have read our article on DUI breath tests, then you know that Breathalyzer results can sometimes be inaccurate.  While IIDs are generally fairly accurate, they can, in some cases, provide false-positive results.  Unlike passing a typical DUI test, starting your car with an IID, usually will require that no alcohol whatsoever is in your breath.  Some common products, such as mouthwash, contain alcohol, which could register in an IID test.  Because the results are reported to the court, people are often worried about generating false-positive results.  However, if a small amount of alcohol is registered, you typically will be given the opportunity to test again.  In most cases, if you truly had not consumed alcohol, letting a short amount of time pass should be sufficient for trace amounts of alcohol to disappear from your breath. 


In San Diego and Orange Counties, ignition interlock devices (IID) are being increasingly required of DUI offenders, particularly in cases where the blood alcohol concentration (BAC) is above 0.15%, following second DUI offenses, or cases involving an accident. The IID is a small breath-analyzing instrument that is installed in a vehicle, connected to the ignition device. The car will not start unless the operator blows an alcohol-free breath sample into the unit. This function is to prevent an intoxicated person from being able to operate the motor vehicle.

How They Work

If a judge has ordered that an IID be installed as part of your sentencing, it must be professionally installed in each vehicle you own or drive. (Employer-owned vehicles and motorcycles are exempt.) When attempting to use your vehicle, you must blow into the IID, providing a breath sample free of any trace of alcohol. If any alcohol is present, the car will not start and the IID will record a positive test result in its memory. The IID will also require additional breath samples, known as “rolling tests”, periodically while the car is in use. Rolling tests allow enough time for the driver to safely pull over in order to provide a breath sample. If traces of alcohol are detected during a rolling test, the IID will record a failed sample and those results will be communicated to authorities.

The IID is designed to ensure that only the driver of the vehicle is able to provide a breath sample. This is accomplished by requiring that the person assigned an IID uses a specific breath pattern when providing a breath sample. The IID is attached by a cord, which cannot reach to the passenger or back seat area.

It is important to know that if you are assigned an IID following a DUI offense, it is a crime to ask another person to provide a breath sample in place of your own. The IID will also record any attempt to tamper with or disable the device. Technology used in the IID has the ability to eliminate chances of contaminated breath samples by cigarette smoke, perfume, etc. There is no minimum threshold for alcohol presence, and any trace on your breath will register as a positive result, which would include alcohol present from mouthwash or any foods containing small amounts of alcohol. If you do register a positive result for alcohol, the IID will give you an opportunity to retest almost immediately.

When They Might Be Required

A judge may order the installation of a California IID for any type of violation that is related to driving under the influence, including the following offenses:

- Driving under the influence - VC23152(a)

- Driving or operating a motor vehicle with a blood alcohol concentration of 0.08% of greater - VC23152(b)

- DUI resulting in injury - VC23153

- Driving while your privilege to drive is suspended or revoked due to a previous DUI conviction – VC14601

Courts have the power to order that an IID be installed in your vehicle for up to 3 years in any case where the judge feels it is appropriate to do so. As a general rule, this occurs only after a first offense DUI when the BAC is above 0.15% or if the person refuses to submit to a breathalyzer or blood test at the time of arrest.

The Cost

Costs of an IID will vary depending on the type of device and the work involved in installing it in your vehicle. On average, the cost of a California IID is about $2.50 per day. You could be charged for installation of the device, which generally costs $75 to $150 when done by an authorized installer. Fees for reporting, maintenance and calibration of your IID are commonly assessed.

Our Lawyers At The San Diego Dui Attorney Have The Experience And Resources To Provide You With The Defense You Deserve.  Contact Us Today For Your Free Dui Consultation.

The experienced criminal defense attorneys at the San Diego DUI Attorney can assist you in your legal defense and the repercussions following a DUI arrest. Ross Law Center specializes in DUI and Criminal Defense Law, serving clients in San Diego, Vista, El Cajon, Oceanside, Chula Vista and other San Diego County communities.

Contact Our Office Today At 619-535-7150 For A Free Dui Consultation.