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Ignition Interlock Devices (FFDL 31)

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What Is an Ignition Interlock Device (IID)?

An IID is about the size of a cell phone and wired to your vehicle's ignition. After installation, the IID requires your breath sample before the engine will start. If the IID detects alcohol on your breath, the engine will not start. As you drive, you are periodically required to provide breath samples to ensure the continued absence of alcohol in your system.

Can IIDs Prevent Drunk Driving?

Yes. The International Council on Alcohol, Drugs and Traffic Safety maintains that IIDs, when combined with a comprehensive monitoring and service program, lead to a 40–95 percent reduction in the rate of repeat drunk driving offenses among offenders as long as the IID remains on the vehicle.

Court-Ordered IID Restriction

When the court orders the use of an IID, you must have one installed by an authorized installer and provide proof of installation to the court. The court has special forms and procedures to monitor drivers ordered to have an IID installed. After the Department of Motor Vehicles (DMV) is notified by the court, DMV places a restriction on your driver license (DL) and marks your driving record so law enforcement officers are aware of the IID requirement if you are stopped. If you fail to comply with a court-ordered IID restriction, the court will notify DMV and your driving privilege may be suspended until you comply with the court order.

DMV-Ordered IID Restriction

DMV is required to impose an IID restriction on your driving privilege when you are convicted of driving with a suspended or revoked DL for a driving under the influence (DUI) conviction (California Vehicle Code (CVC) §§14601.2, 14601.4, or 14601.5).

This restriction does not allow you to drive without a valid DL.

You must submit either a Verification of Installation Ignition Interlock (DL 920) or Exemption for Ignition Interlock Device (DL 4054B) form to DMV within 30 days from the date the Order of Installment of an Ignition Interlock Device (DL 4054A) form was mailed. These forms ensure that you and the installer agree to the terms of the IID restriction.

Optional DMV IID

Restriction Requirements

If you were convicted of a DUI (CVC §§23152 or 23153) or “wet reckless,” (CVC §23103.5) you may be eligible for an IID-restricted DL. In addition to any other specified restriction requirements, you must meet the following requirements:

  • Clear all other outstanding suspensions/revocations on your driving record.
  • Comply with a DUI program's requirements and have the program provider submit  the appropriate Proof of Enrollment Certificate (DL 107) or Notice of Completion Certificate (DL 101) form to DMV (whichever applies to your case).
  • Submit to DMV a California Insurance Proof Certificate (SR 22) form issued by your auto insurance company that establishes proof of financial responsibility.
  • Install an IID on your vehicle and provide DMV with a DL 920.
  • Pay all required fees.

All required forms and fees may be submitted to any local DMV office or mailed to: 

Department of Motor Vehicles 
MS J233
PO Box 942890
Sacramento, CA 94290-0001

NOTE: Call DMV at (916) 657-6525 for assistace to determine eligibility for obtaining a restricted DL.

Multiple DUI Violations 

If you were convicted of a second or subsequent DUI violation and have completed at least one year of your DUI suspension/revocation, you may qualify for a restricted DL if you meet the restriction requirements. 

Second and Third DUI Violations–Alcohol Only

If your violation occurred on or after July 1, 2010, you may receive a shorter suspension/revocation period if you have a second or third DUI conviction under CVC §23152 that involved alcohol only. For example, if you have a second DUI violation that involved alcohol only, you may reinstate driving privileges after a 90-day suspension. If you have a third DUI violation that involved alcohol only, you may reinstate after a 6-month revocation.

In addition, you will need to meet the restriction requirements.

Second APS Suspension and Wet Reckless Violation

If your violation occurred on or after January 1, 2012, and you were convicted of a "wet reckless" as a substitute for a DUI conviction, you may opt to end your 1-year administrative per se (APS) suspension after 90 days.

In addition, you will need to meet the restriction requirements.

Court-Ordered 10-Year Revocation

If your violation occurred on or after January 1, 2012, you have three or more separate DUI convictions, and are revoked for 10 years under CVC §23597, you may be eligible for early reinstatement of your driving privilege with an IID-restricted DL. To be eligible for early reinstatement, you must serve five years of the revocation period, have no alcohol or drug offenses during the revocation period, and must provide a DL 101 for an 18 or 30-month DUI program, and provide a DL 920.

IID Pilot Program

Effective July 1, 2010, legislation requires DMV to conduct an IID pilot program. If you are a pilot program participant, refer to the Ignition Interlock Device (IID) Pilot Program (FFDL 44) Fast Facts brochure for additional information.

IID Providers 

A list of DMV-certified IID manufacturer contact information is available at

Check the License of an IID Installer

All IID installation facilities doing business in California are required to have a valid license issued by the Bureau of Automotive Repair (BAR) or the Bureau of Electronic and Appliance Repair, Home Furnishings and Thermal Insulation (BEARHFTI), which are part of the Department of Consumer Affairs (DCA). To ensure that an IID installer is properly licensed, see the BAR website at

IID Calibration and Monitoring

Once installed in your vehicle, the IID must be calibrated and inspected by a certified installer at intervals not to exceed 60 days. Your installer ensures the device is working properly and that no violations, such as failing to take random retests, have been logged. Noncompliance with IID requirements are reported to the court or DMV (whichever applies) and you may have your driving privilege suspended or revoked.

Certain violations require DMV to immediately suspend or revoke your driving privilege if you have an optional IID restriction (for example, an attempt to remove, tamper with, bypass, or failure to comply with any requirement for IID maintenance or calibration). DMV may restore the IID-restricted driving privilege upon receipt of a new DL 920.

Installation and Monitoring Fees

IID installation and monitoring fees vary among IID service providers. Call IID manufacturers for price quotes.


FFDL 31 (REV. 8/2017)


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