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Ignition interlock in Missouri

In Missouri, a court decides whether you get an interlock after a first intoxication-related offense and must order one after a second or later offense. The Missouri Department of Transportation certifies the devices, and the Department of Revenue handles license reinstatement.

Checked Oct 23, 2026Sources
First offense: only at a high BAC
First offense, to drive during the post-conviction suspension
no, unless offenders' BAC at or above 0.15
First offense, as a penalty or to get the license back
no
Repeat offense, as a penalty or to get the license back
yes
IIHS, October 20261

    286 locations in Missouri from the companies' own locators. Distances are straight-line; call to confirm the location services your device.

    Each dot is a service location listed by an interlock company. Orange rings mark your search.Company locators, Oct 2026

    Who has to install one in Missouri

    Your situationInterlockHow longLaw
    First offense, BAC below 0.15, no injury or damageCourt decidesNot statedRSMo 302.4402
    First offense, BAC 0.15 or higherRequiredNot statedRSMo 302.4402
    First offense that caused property damage or injuryRequiredNot statedRSMo 302.4402
    Second or later intoxication-related offenseRequiredAt least 6 months from reinstatementmodot.org3
    Driving a company vehicle for an employerEmployer not requiredNot statedmodot.org4

    A judge can order an interlock in other cases too. Your court order or DMV letter is what binds you.

    Where each company can install in Missouri

    You'll go back to the same company's locations for service for the whole order, so check that one is close to where you live and work before you book.

    Locations as each company lists them on its own locator (Smart Start, Intoxalock, LifeSafer, Low Cost Interlock, RoadGuard), pulled Oct 2026. Some shops serve more than one company. Alcohol Detection Systems doesn't publish a locator we could read.

    Interlock companies approved in Missouri

    From the state's approved list (read it). Use a company on this list, or the install won't count. 12-month figures are lease, install and removal from each company's filed or published fee schedule, not Missouri prices; see how we add them up.

    How much an interlock costs in Missouri

    Estimated total for your order

    1. LifeSafer
    2. Low Cost Interlock
    3. RoadGuard
    4. Intoxalock
    5. Smart Start

    Lease times the months you pick, plus install, removal and any enrollment fee, from each company's filed or published schedule (New York filing, Feb 2025; National schedule, Sept 2026; New York filing, 2021; New York filing, Feb 2021; New York filing, Apr 2025). Missouri prices can differ; calibration visits and lockout fees come on top.

    If you can't afford it

    Providers must offer a discounted fee if your income is at or below 150% of the federal poverty level, and you then pay 10% of the device cost. Extra costs from noncompliance are not discounted. You can show eligibility with last year's federal tax return, income statements from the last three months, or a court order.

    Financial help in other states

    The rules in Missouri

    Program run by
    The Missouri Department of Transportation certifies devices, and you can reach its Highway Safety and Traffic Division at 800-800-2358. The Department of Revenue handles license reinstatement at 573-526-2407.3
    License you get
    You drive on a limited or restricted driving privilege that requires the interlock device (RSMo 302.309 and 302.525).5
    Time on the device
    The minimum is six months from the date your license is reinstated. If the device records confirmed alcohol readings or tampering in the last three months of those six, the period runs until you have three consecutive months without a violation.6
    Help paying
    Providers must offer a discounted fee if your income is at or below 150% of the federal poverty level, and you then pay 10% of the device cost. Extra costs from noncompliance are not discounted. You can show eligibility with last year's federal tax return, income statements from the last three months, or a court order.7
    Getting it removed
    The counting period starts the day the Department of Revenue receives notice from the device manufacturer. After that period you can have the device removed once your other reinstatement requirements, such as SATOP and insurance, are met. The Department of Revenue can answer questions at 573-526-2407.8
    Violations
    A conviction for driving without a required device revokes your driving privilege for 1 year the first time and 5 years the second time, according to MoDOT. If you fail to keep proof of the device, your license is suspended again. Lending or renting a vehicle without a device to someone with this restriction is a class A misdemeanor (RSMo 577.600).9
    Driving for work
    Missouri law does not require employers to install interlocks on company vehicles.4
    Out-of-state license
    If you live outside Missouri and have no approved provider near you, call the MoDOT Traffic and Highway Safety Division at 800-800-2358.10

    Questions about interlocks in Missouri

    How long do you have to have an interlock in Missouri?

    The minimum is six months from the date your license is reinstated. If the device records confirmed alcohol readings or tampering during the last three months of that period, you keep it until you have three consecutive months without a violation, so the total time can run longer than six months.6

    Can I get help paying for an interlock in Missouri?

    Yes, if your income is at or below 150% of the federal poverty level. Providers must offer a discounted fee under which you pay 10% of the device cost, though extra costs from noncompliance are not discounted. You can verify income with a federal tax return, three months of income statements, or a court order.7

    How do I get an interlock removed in Missouri?

    Removal is allowed after your counting period ends, which starts the day the Department of Revenue receives notice from the device manufacturer. You also need to have met your other reinstatement requirements, such as SATOP and insurance. For questions about your case, call the Department of Revenue at 573-526-2407.8

    What happens if I drive without an interlock in Missouri?

    A conviction for operating without a required device revokes your driving privilege for 1 year on a first conviction and 5 years on a second, according to MoDOT. Failing to keep proof of the device on file leads to another license suspension.9

    Does my employer have to put an interlock in a work vehicle in Missouri?

    No. Missouri law does not require employers to install ignition interlock devices on company vehicles. The facts available here do not cover how the requirement applies if you must drive a work vehicle, so ask the court or the Department of Revenue about your situation.4

    Related guides

    InterlockCompare is independent and doesn't make, sell or install interlocks. Not legal advice.

    Sources

    1. Missouri: first offense, post-conviction suspension: no, unless offenders' BAC at or above 0.15iihs.org/research-areas/alcohol-and-drugs/alcohol-interlock-laws-by-state
    2. a court may require that any person who is found guilty of a first intoxication-related traffic offenserevisor.mo.gov/main/OneSection.aspx
    3. modot.org/node/462
    4. Missouri law does not require employers to install ignition interlock devices on company vehiclesmodot.org/node/462
    5. limited driving privilegerevisor.mo.gov/main/OneSection.aspx
    6. for a period of not less than six months immediately following the date of reinstatementrevisor.mo.gov/main/OneSection.aspx
    7. shall be responsible for ten percent of the cost of the ignition interlock devicerevisor.mo.gov/main/OneSection.aspx
    8. begins the counting period on the day notification from the ignition interlock manufacturer is receivedmodot.org/node/462
    9. revoked for five yearsmodot.org/node/462
    10. 800.800.2358modot.org/node/462