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.

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

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

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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 camera and 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.

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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 denied for five years.

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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:

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What is considered a violation of the device?

A violation is defined, by law, as any incident of device tampering, circumvention, or confirmed breath alcohol level of .025 percent or more. Sections 302.060; 302.304; 302.525; 577.041, RSMo; and 7 CSR 60-2.010.

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

If you have any questions or concerns about IID violations reported to the Department by the IID manufacturer, you must contact the manufacturer.

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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.

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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.

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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 six-month period (184 days) after reinstatement will result in a re-suspension of driving privileges for the remainder of the six-month period plus assessment of an additional six-month period of IID requirement. You will then be required to do the following before your Missouri driving privilege can be reinstated:

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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.

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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.

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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.

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Still need help? You can also submit your driver licensing questions to our staff by e-mail. Your e-mail 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 e-mail response.