Ignition Interlock Device (IID)

What is an Ignition Interlock Device (IID)?

An Ignition Interlock Device (IID) is a handheld breath-testing device that is connected to the vehicle's ignition, horn, and headlights. To start the vehicle, a driver must blow into the device without registering a blood alcohol concentration (BAC). Some IID units are equipped with camera and GPS.

Why do I need an Ignition Interlock Device (IID)?

Based on driving history, you may be required to have an IID installed prior to:

Does my ignition interlock device (IID) need to be equipped with camera and GPS features?

If you are seeking a court-ordered Limited Driving Privilege (LDP) or court-ordered reinstatement because your Missouri driving privilege is currently under a 5- or 10-year denial, you are required to install an IID equipped with a camera. The court may require that the IID be equipped with GPS.

If your Missouri driving privilege is not currently under a 5- or 10-year denial, the camera and GPS features are not required unless ordered by the court.

What maintenance is required for an Ignition Interlock Device (IID)?

After installation of the IID, you are required to report to a certified IID installer each month for maintenance to ensure the device is working properly. The manufacturer will also download information from the device to create a "monthly monitoring report" to check for any violations you may have.

NOTE: In addition to the IID requirements explained above, a court may impose other requirements, such as an IID period longer than six months. If you are convicted of failing to have an IID installed as required by law, your driving privilege will be revoked for one year. A second offense requires driving privileges to be revoked for five years.

What will happen if my monthly monitoring reports show a violation of the device?

If your monthly monitoring reports show a violation of the device, you will be required to maintain the device on your vehicle for an additional period of time:

  • An additional 30 days if you were issued an Immediate 90-Day Interlock Restricted Driving Privilege (RDP); or
  • If you were required to install the IID for reinstatement of your Missouri driving privilege and your violation occurred during the last three months of the monitoring period, you must maintain your device until you complete a 3-consecutive-month period without violations.

What is considered a violation of the device?

A "violation" is defined in 7 CSR 60-2.010.37 (violations reset).

What if I disagree with the violation shown on the monitoring reports?

If you have any questions or concerns about an IID violation, you must contact the device manufacturer.

What happens if I am driving on a Limited Driving Privilege (LDP) and I fail to have the Ignition Interlock Device (IID) serviced as required, or I have it removed early?

Failure to maintain the device while driving on a Limited Driving Privilege (LDP) will result in a termination of the LDP. The IID must also be maintained for the entire period of your Limited Driving Privilege (LDP). Before you may resume driving, you must install or have the device serviced, and then apply for (and be granted) a new LDP.

What happens if I am driving on a Restricted Driving Privilege (RDP) and I fail to have the Ignition Interlock Device (IID) serviced as required, or I have it removed early?

Failure to maintain the device while driving on a Restricted Driving Privilege (RDP) will result in a termination of the RDP. Before you may resume driving, you must install or have the device serviced and then contact the Department of Revenue for assistance.

What happens if my driving privilege has been reinstated and I fail to have the Ignition Interlock Device (IID) serviced as required, or I have it removed early?

Failure to maintain the device during the required period after reinstatement will result in a re-suspension of driving privileges. You will then be required to do the following before your Missouri driving privilege can be reinstated:

  • Have the IID serviced or reinstalled (the certified installer will send proof of service or reinstallation to the Driver License Bureau); and
  • Pay a $20 reinstatement fee. You may pay your reinstatement fee online as mydmv.mo.gov using the following credit/debit cards: Visa®, MasterCard®, Discover®, and American Express®.

It is possible to prevent the suspension from going into effect if you submit and the Department timely receives acceptable proof that the IID has been installed or serviced as required by law.

When can I remove the device from my vehicle without any penalty?

You should not remove the device until you verify with the Department of Revenue that you are allowed to do so. Early removal of the device may result in the re-suspension of your driving privilege and an extension of the period that the IID must be maintained.

How will the Department of Revenue know I maintained the device without violations?

The manufacturer of the device is required to electronically notify the Department if you maintained your device for the required length of time without violations. Once the Department has received certification from the manufacturer, you may remove your IID without penalty.

How do I find an Ignition Interlock Device (IID) installer?

The IID must be certified and approved by the Missouri Department of Transportation (MoDOT).

For information about approved devices, visit the MoDOT website or call 800-801-3588.

Still need help? You can also submit your driver licensing questions to our staff by email. Your email will be forwarded to the appropriate area for reply. Some inquiries can be responded to more quickly than others depending on the issue and amount of time needed for research. Please make sure your computer will accept our email response.