
Missouri requires IID for repeat offenders before driving privileges are reinstated.
This information should not be considered legal advice. This is general information and subject to change. Specific situations involving DWI offenses may have varying results. Anyone needing legal advice on a DWI or driver’s license revocation should obtain legal advice from an attorney.
A new law has gone into effect in Missouri requiring repeat DWI offenders to install an in car breathalyzer or ignition interlock device (IID) in their vehicle. The ignition interlock is required for repeat offenders in Missouri for driving while intoxicated (DWI), driving with a blood alcohol concentration level (BAC), or driving under the influence of drugs (DUID).
The ignition interlock device is required for six months beginning at the date of reinstatement, when the license suspension or revocation ends, for the Missouri driver’s license. During the six month period when the ignition interlock is active the offender will have to have it periodically examined and calibrated to ensure compliance. This means going to a certified IID vendor for maintenance each month. The time period required for the breathalyzer (IID) may be longer than six months if the driver has Limited Driving Privilege (LDP). With a LDP the IID must remain installed for the entire time there is a limited driving privilege.
In Missouri the ignition interlock device will be installed to connect with the car’s ignition, the horn, and the headlights. The connection to the ignition prevents the vehicle from starting if alcohol is detected in the driver’s breath before trying to start the car. There must be no blood alcohol concentration to start the car. If the ignition interlock device detects alcohol in the driver’s breath once the car is started the horn and lights will be activated to alert law enforcement officers. This prevents drivers from trying to cheat the ignition interlock device (IID).
Failing to maintain the breathalyzer during the six month period following reinstatement or during the Limited Driving Privilege period will result in a re-suspension of driving privileges. To get another reinstatement will require servicing the ignition interlock (IID) and paying a $20 fee. There may be further suspensions or revocations for driving without having installed an ignition interlock (IID) or in car breathalyzer.
To meet the requirements for reinstatement of Missouri driving privileges the ignition interlock device (IID) must be installed by a vendor that is certified by the Missouri Department of Transportation.
The Missouri DOT website has a list of certified IID vendors and installers. The list includes certified ignition interlock device (IID) installers in Kansas City, St. Louis, St. Charles, Union, Springfield, West Plains, Joplin, Jefferson City, Independence, Columbia, Farmington, Hannibal, and many other Missouri cities. The list includes the name of the ignition interlock/in car breathalizer vendor and the city, address, and phone number.
Prices for the ignition interlock device may vary depending on the vendor/installer but will likely range from $50 to $200 for installation and $50 to $100 for renting the device. Other costs may include maintenance, downloads, and calibration of the breathalyzer. The Missouri DOT states that an average ignition interlock device costs $800 per year.
The breath alcohol ignition interlock device, or in car breathalyzer, models available for installation in Missouri include: Consumer Safety Technology – Intoxalock-Model 1001A, Draeger Interlock XT, LifeSafer FC-100, Guardian Interlock Systems – AMS 2000, Smart Start – SSI-1000, Smart Start – SSI 20/20, and Alcohol Detection Systems – Determinator DM-904.









