Ignition Interlock

Substance-Impaired driving contributes to more than 20 percent of all Missouri traffic fatalities

A breath alcohol ignition interlock device (BAIID) is a breath testing device, including all parts necessary for operation, e.g., handset and camera, installed in a vehicle that prevents it from operating if the breath test registers a breath alcohol concentration that meets or exceeds the alcohol set point.  The device also requires the driver to continue to pass repeated breath tests while the vehicle is running to ensure that the driver remains below the alcohol set point.  However, the interlock device will not interfere with the normal operation of the vehicle while it's in use.

Missouri law requires any person guilty of a second or subsequent intoxication-related traffic offense to install an ignition interlock device on any vehicle they operate before reinstating driving privileges.

Each ignition interlock provider is responsible for reporting ignition interlock compliance to the Department of Revenue and/or the court-ordered supervising authority.

To view the Administrative Rules which establish the standards for the Breath Alcohol Ignition Interlock Device Certification and Operational Requirements visit http://www.sos.mo.gov/adrules/csr/current/7csr/7csr.asp.

If you are required to have an ignition interlock device installed, call the manufacturers listed below to obtain information regarding installation, pricing and locations around the state. Make sure that the device you have installed is one of the approved devices listed below. The State of Missouri and/or their employees do not endorse or recommend manufacturers. Each manufacturer is a commercially operated company that has been approved by the State of Missouri according to 7 CSR 60-2. Rates and policies may vary.

Name of Manufacturer Approved Device contact
LifeSafer L250 800-765-1188
Smart Start

SSI 20/20

SSI 20/30 

SSI 20/35 

SSI FLEX 30/30

Low Cost Interlock LCI-777 800-352-4872
Alcohol Detection Systems (ADS) Determinator 2  833-996-2560
Intoxalock  1001A 844-328-1967


Frequently Asked Questions

When are ignition interlock devices required?

Individuals with more than one intoxication-related traffic offense on their driving record must have an ignition interlock installed prior to:

  • reinstatement of their driving privilege, or
  • issuance of a limited driving privilege or restricted driving privilege. Note that in these cases the ignition interlock must be maintained during the duration of the limited or restricted driving privilege.

In addition to the driver licensing requirements explained above, a court may impose other requirements. The use of ignition interlock devices may be required for a first intoxication-related traffic offense and shall be required for a minimum of six months for any person with a second or subsequent intoxication-related traffic offense. Please note that a court may impose a period longer than six months.

How much does this cost?

MoDOT does not keep a pricing list. The costs vary among the ignition interlock companies. For pricing information contact each of the ignition interlock companies in your area.

What vehicle do I need the device installed in?

Missouri law states that the individual shall not operate any motor vehicle unless that vehicle is equipped with a functioning, certified ignition interlock device. If a driver is convicted for failing to have an ignition interlock installed as required by law, their driving privilege will be revoked for one year. A second offense requires driving privileges to be revoked for five years.

Who processes the paperwork for installation of a device?

The ignition interlock manufacturers are responsible for reporting to the Department of Revenue and/or the court supervising authority.

What if I do not have a vehicle?

You do not have to own the vehicle that you install the device in but you do have to install an ignition interlock device in any vehicle you operate. If that is not possible then you will not be able to reinstate your driving privileges.

Does the law require employers to install ignition interlock devices for their employees?

Missouri law does not require employers to install ignition interlock devices on company vehicles for their employees. However, the employee cannot drive company vehicles without an ignition interlock device installed and therefore will need to make other arrangements.

When will my driver's license be reinstated?

For questions related to your limited driving privilege (LDP), license reinstatement date, ignition interlock electronic log reporting, or any other driver's license related inquires, contact the Missouri Department of Revenue at 573-526-2407 or visit https://dor.mo.gov/drivers/reinstatement.php


What if I live in another state?

Missouri law applies to individuals who live in another state if they have received two or more intoxication-related offenses in Missouri. Ignition interlock programs vary across the United States. The individual must meet all of the same requirements as Missouri residents. It is important to use a device that is approved for use in the State of Missouri and that the information is reported to the Department of Revenue and/or court supervising authority (if applicable). There are currently five manufacturers that have devices approved for use in the State of Missouri. For a list of approved devices and to check on availability in a particular state call the customer service numbers found on the list of installers for Missouri. The customer service numbers go directly to the manufacturers. The customer service representative should be able to assist you in finding a location near you if they provide service in that state. If you are unable to locate an approved provider in the state you are located then you need to contact the Missouri Department of Transportation, Traffic and Highway Safety Division at 800.800.2358 for more information.

Can two people share one ignition interlock device?

No, each ignition interlock device is assigned to a specific person and reporting information is tracked accordingly.

When can I have the ignition interlock device removed?

The Department of Revenue begins the counting period on the day notification from the ignition interlock manufacturer is received, providing all other reinstatement requirements (SATOP, insurance, etc) have been met. Please contact the DOR if you are not sure when the ignition interlock device can be removed.

Is it dangerous to provide a running retest?

Ignition interlocks are programmed to allow a few minutes to perform the breath test, enough time to pull over.

Could an interlock stop a person’s car in traffic, making a more dangerous hazard?

Ignition interlocks are connected to a vehicle’s starter system, not the engine itself. The interlock does not have the ability to stop the vehicle once it is running for safety reasons. When a driver fails a running retest, the vehicle’s horn will honk and/or the lights will flash to alert law enforcement – the vehicle will not stop.

Aren’t ignition interlocks an inconvenience to family members who share the offender’s vehicle?

No, family members are allowed to drive the vehicle as well. They simply must not drink and drive. Having an interlock installed on a vehicle actually allows the offender to continue to drive legally and allows other family members to use the vehicle as well. Other sanctions like vehicle impoundment or immobilization do not allow for this.