Missouri calls it DWI, not DUI. What are the actual elements of the offense?

Missouri's DWI offense is defined in RSMo § 577.010: a person commits the offense of driving while intoxicated if they operate a motor vehicle while in an 'intoxicated or drugged condition.' 'Intoxicated condition' means under the influence of alcohol. 'Drugged condition' means under the influence of a controlled substance or drug, including marijuana. Elements the prosecution must prove: (1) Operation of a motor vehicle: Missouri courts have interpreted 'operation' broadly — sitting in the driver's seat with the engine running while parked can constitute operating a motor vehicle under Missouri law (similar to Massachusetts OUI doctrine). Moving the vehicle is not required; control of the vehicle while intoxicated is the key element; (2) In an intoxicated or drugged condition: this means impaired to the extent that the driver lacks the ability to operate the motor vehicle safely. The separate per se statute (RSMo § 577.012) adds a second offense: driving with a BAC of .08% or higher, which is a per se violation regardless of whether the driver appeared impaired. Prosecutors often charge both offenses simultaneously; (3) BAC evidence: breath test results from Missouri-approved devices (most commonly the Datamaster or equivalent) are admissible if the test was properly administered by a certified operator following Missouri Department of Health and Senior Services protocols. Field sobriety tests (FSTs) — Horizontal Gaze Nystagmus (HGN), Walk and Turn, One-Leg Stand — are used as preliminary evidence but are not per se determinative; (4) Marijuana DWI: since Amendment 3 legalized recreational marijuana in Missouri in 2022, law enforcement has increasingly deployed Drug Recognition Experts (DREs) for suspected marijuana-impaired driving. Unlike alcohol, there is no per se THC threshold in Missouri law — the prosecution must prove actual impairment (drugged condition) through observation, DRE evaluation, and chemical testing (blood test for THC, not breath).

I refused the Missouri breathalyzer. What happens to my license?

Missouri's Implied Consent Law (RSMo § 577.020) and license revocation procedures: (1) Refusal consequences: refusing the chemical test (breath, blood, or urine as designated by the officer) results in an administrative license revocation of 1 year for a first refusal. For a second refusal within 5 years: 1-year revocation again, but the person is not eligible for a limited driving privilege during that year (unlike first-refusal where limited privilege may be available); (2) The 15-day clock: upon arrest and refusal, the officer confiscates your Missouri driver's license (or issues notice if you have an out-of-state license) and issues a Notice of Revocation and 15-day temporary license. Within those 15 days, you must request an administrative hearing by contacting the Missouri Department of Revenue (Form 2385 — Petition to Review — filed with the DOR). Failure to request within 15 days waives the right to an administrative hearing and the revocation becomes effective on day 31 after arrest; (3) The administrative hearing: the administrative hearing before a DOR hearing officer (not a judge) reviews: whether the officer had probable cause to believe you were DWI; whether you were placed under arrest; whether you refused the test; and whether you were properly informed of the consequences of refusal. If the hearing officer finds all elements, revocation is upheld. If the arresting officer fails to appear, many DOR hearing officers dismiss the revocation. The administrative record created at the DOR hearing is important because it is sometimes used at the criminal DWI trial; (4) Limited driving privilege (LDP): a first-refusal driver whose revocation is upheld may petition for a limited driving privilege through the circuit court (not DOR) allowing driving for employment, school, and essential purposes with an Ignition Interlock Device; (5) Refusal vs. submitting and failing: in Missouri, taking a breath test and failing (.08%+ result) also leads to administrative suspension (90 days for first offense). Some defense attorneys advise clients that a refusal, while causing a longer license revocation, avoids providing direct BAC evidence for the criminal case — but this is a complex strategic decision with significant downsides on both the administrative and criminal sides.

Missouri DWI penalties — how bad is a first offense?

Missouri's first-offense DWI penalties (RSMo § 577.010, Class B misdemeanor for BAC .08%-.149% with no aggravating factors): Criminal penalties: maximum 6 months in county jail and $1,000 fine plus court costs and assessments. Missouri courts often impose probation for first-time DWI offenders rather than jail, particularly with clean prior records and cooperation with the court's conditions. Missouri Suspended Imposition of Sentence (SIS): Missouri's criminal procedure allows courts to impose an SIS — the court accepts a guilty plea, imposes probation conditions, but does NOT formally sentence the defendant. If the defendant successfully completes probation (typically 2 years for DWI), the court does not formally enter the conviction. An SIS outcome means the person can truthfully say they have not been convicted of DWI on most applications. However: (a) the SIS is NOT expungeable under § 610.140 because the statute prohibits expungement of DWI offenses, and DOR still records the SIS for license purposes; (b) a subsequent DWI after an SIS still counts as a prior offense for sentencing enhancement purposes; License consequences (separate from criminal): 90-day administrative suspension if BAC test was taken and showed .08%+; no suspension for first offense if test was refused but the administrative revocation from refusal is 1 year; SATOP completion required for reinstatement; Ignition Interlock Device (IID): Missouri requires IID for reinstatement of driving privileges for first-offense DWI offenders with a positive BAC test (RSMo § 302.304). IID must be maintained for 6 months for first offense; Financial total: first-offense DWI in Missouri typically costs $2,500-$6,000+ including fines, court costs, SATOP fees ($125-$300+), IID installation and monitoring ($70-$100/month), and attorney fees.

What defenses are available in a Missouri DWI case?

Missouri DWI defenses: (1) No reasonable suspicion to stop: the 4th Amendment and Missouri Constitution Art. 1, § 15 prohibit pretextual or suspicionless traffic stops. If the officer lacked reasonable articulable suspicion of a traffic violation or criminal activity to justify the initial stop, the entire stop may be suppressed, eliminating all evidence gathered from it. Common stop challenges: ambiguous traffic violation (did the driver actually fail to signal?); checkpoint procedural violations (Missouri sobriety checkpoints must follow State v. Moul, 872 S.W.2d 228 supervisory authorization requirements); (2) No probable cause to arrest: even if the stop was valid, the officer must have probable cause to believe the driver was DWI before arresting them and requesting chemical testing. Failed field sobriety tests (HGN, Walk and Turn, One-Leg Stand) are the primary basis for DWI arrest probable cause; challenges to FST validity include: road surface conditions, lighting, driver's physical conditions (medical conditions affecting balance), weather, improper administration by officer; (3) Breathalyzer calibration and protocol: Missouri's Datamaster breathalyzer must be calibrated and maintained according to Missouri DHSS regulations. Defense attorneys request maintenance and calibration records (DHSS Form 1). If the device was out of calibration or not properly maintained, the result may be suppressed; (4) Rising BAC defense: if the driver's BAC was below .08% at the time of driving but above .08% at the time of testing (30-60 minutes later), the BAC was 'rising' — expert testimony on alcohol absorption curves can argue that the legal BAC limit was not exceeded while the driver was actually operating; (5) Medical conditions: diabetes (can produce acetone that registers as alcohol on breathalyzers), GERD (gastroesophageal reflux can cause mouth alcohol contamination of breath tests), medications, and head injuries can affect breathalyzer results or mimic intoxication symptoms.

Missouri marijuana is legal now. Can I drive after using it?

Missouri's Amendment 3 (2022) legalized adult recreational marijuana, but driving while impaired by marijuana remains illegal under RSMo § 577.010 (DWI — 'drugged condition'). Key distinctions: (1) No per se THC limit: unlike alcohol (.08% per se), Missouri has NO per se blood THC threshold for DWI. A driver with detectable THC in their blood is NOT automatically committing DWI — the prosecution must prove actual impairment (a 'drugged condition' that affected the driver's ability to operate safely). This contrasts with some states (Washington, Colorado) that have adopted 5 ng/mL active THC per se limits for driving; (2) Drug Recognition Experts (DREs): Missouri State Highway Patrol has expanded its Drug Recognition Expert program post-Amendment 3. DREs are officers trained in a 12-step protocol to evaluate suspected drug-impaired drivers. The DRE evaluation includes eye examinations, pulse rate, blood pressure, temperature, muscle tone, and injection site examinations — the results are used to support a DWI charge for drugged condition. DRE testimony is admissible in Missouri courts (see State v. Lasley regarding expert testimony standards); (3) Blood testing for THC: unlike alcohol (breath test available), marijuana impairment evidence requires a blood draw for THC quantification. Missouri must obtain voluntary consent or a warrant before blood draw (Missouri v. McNeely, 569 U.S. 141, 2013 — the U.S. Supreme Court held warrantless nonconsensual blood draws in DWI cases generally violate the 4th Amendment unless exigent circumstances exist); (4) Defense challenges to marijuana DWI: challenging DRE protocol compliance; challenging whether the THC level present caused actual impairment (as opposed to residual THC from prior legal use); noting that THC metabolites can remain in blood for days or weeks after use without active impairment; (5) Combined alcohol and marijuana: if a driver is over .08% BAC AND has marijuana in system, the case is typically charged as both the per se alcohol DWI and drugged condition DWI — the combination is argued to increase impairment beyond either substance alone.

DUI & Traffic Laws in Missouri (2026)

DUI & Traffic Violations for Missouri readers: dashcam preservation, document control, and practical next moves

A practical dui & traffic violations guide for Missouri readers who need clearer direction around tow paperwork, dashcam preservation, document control, and early next steps.

Reviewed January 2026 3 min read Official-source grounded Ver en Espanol En Español

Key Takeaways

Missouri calls it DWI (not DUI): RSMo § 577.010; per se .08% BAC (§ 577.012); 'drugged condition' covers marijuana/controlled substances — but NO per se THC threshold; DRE evaluations required for marijuana impairment proof
First DWI: Class B misdemeanor (6mo/$1K max); SIS (Suspended Imposition of Sentence) option avoids formal conviction if probation completed; IID + SATOP required for reinstatement
Implied consent (RSMo § 577.020): refusal = 1-yr administrative revocation (DOR); 15-day window to request DOR hearing; refusal does NOT mean acquittal — field sobriety/DRE evidence still usable
Enhancement ladder: Prior Offender (2 DWIs within 5yr) = Class A misdemeanor; Persistent Offender (3+ DWIs) = Class D felony; Aggravated (4+) = Class C felony; DWI with death = Class B felony
Amendment 3 marijuana (2022) complicates DWI enforcement: blood warrant required post-McNeely (2013); DRE expansion; THC detection doesn't automatically prove impairment (no per se limit)

Key Numbers — Missouri All 50 states →

Filing Deadline 5 years

Fault Rule Pure Comparative

Insurance System At-Fault

Key Statute Mo. Rev. Stat. § 516.120

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Missouri is a "DWI state" — the offense is called Driving While Intoxicated (DWI), not DUI (Driving Under the Influence) as used in most other states. Under RSMo § 577.010, a person commits DWI by operating a motor vehicle while in an intoxicated or drugged condition. The per se blood alcohol content threshold is .08% (RSMo § 577.012 — "Driving with Excessive Blood Alcohol Content" creates a separate per se offense). Missouri's DWI law operates in a state that legalized recreational marijuana in November 2022 (Amendment 3), creating new complexity around drug-impaired driving enforcement: Missouri State Highway Patrol drug recognition experts (DREs) have been increasingly deployed to identify marijuana-impaired drivers, as breathalyzers cannot detect marijuana and Missouri's per se DWI law (for BAC) does not automatically cover THC impairment — the prosecution must prove the driver was actually "drugged" (impaired by the drug) rather than just having consumed it.

Missouri's Implied Consent Law (RSMo § 577.020) requires all drivers on Missouri roads to consent to chemical testing of breath, blood, urine, or saliva when lawfully arrested for DWI. Refusal to submit to the chemical test triggers an administrative revocation of driving privileges for 1 year — separate from and in addition to any criminal penalties. Missouri's revocation is administrative, handled by the Missouri Department of Revenue (DOR) through license action, not the criminal court. The driver has 15 days from the date of arrest to request an administrative hearing challenging the revocation (Form 2385). If no hearing is timely requested, the revocation goes into effect on the 31st day after arrest. Missouri's administrative revocation and the criminal DWI proceeding run on parallel tracks — the case outcomes can differ (criminal charges may be dismissed while administrative revocation stands, or vice versa).

Missouri DWI Enhancement Structure

Missouri's DWI offense structure escalates based on prior convictions within a 5-year lookback period: First DWI offense (no prior within 5 years): Class B misdemeanor; up to 6 months in jail; $1,000 fine; 90-day license suspension. DWI with BAC .15% or higher on first offense: Class A misdemeanor (elevated). Second DWI within 5 years (Prior Offender): Class A misdemeanor; up to 1 year in jail; $2,000 fine; minimum 5-year license suspension. Third DWI (Persistent Offender — two or more prior DWIs regardless of when): Class D felony; up to 7 years in prison. Aggravated DWI (three or more prior DWIs): Class C felony; 3-10 years in prison. Chronic DWI (four or more prior DWIs): Class B felony; 5-15 years. DWI resulting in death: Class B felony. DWI resulting in serious physical injury: Class A misdemeanor or Class E felony depending on circumstances. Missouri's "SATOP" (Substance Awareness Traffic Offender Program): first-time DWI offenders are required to complete SATOP as a condition of license reinstatement — a substance abuse education and counseling program. Higher-level offenders require more intensive SATOP intervention (SATOP has multiple levels based on risk assessment).

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