Drugged Driving (DUID) in Missouri in MO — Dui Legal… | CGMIMM
Dui · MO
Drugged Driving (DUID) in Missouri
Missouri drugged driving (DUID) covers driving impaired by drugs — illegal, prescription, or even legal substances. Marijuana legalization complicates many Missouri DUID cases.
Published May 9, 2026
## Drugged driving (DUID) in Missouri
**Drugged driving** (DUID — Driving Under the Influence of Drugs) covers operating a vehicle while impaired by drugs — including illegal drugs, prescription medications, marijuana (where legal), and even over-the-counter drugs. Missouri DUID enforcement has expanded significantly with legalization.
## Substances covered
**Illegal drugs:**
- Cocaine
- Methamphetamine
- Heroin
- LSD / hallucinogens
- Specific schedules I-V
- Strict liability typically
**Prescription drugs (when impaired):**
- Opioids (oxycodone, etc.)
- Benzodiazepines (Xanax, etc.)
- Sleep medications (Ambien)
- ADHD medications (Adderall)
- Other prescriptions
**Marijuana / cannabis:**
- Different rules (legal in some states)
- THC limits in some states
- Active vs metabolic THC
- Specific issues
- Significant legal complexity
**Over-the-counter drugs (when impaired):**
- Cold medications
- Antihistamines (Benadryl)
- Sleep aids
- Specific medications
**Combination:**
- Multiple drugs
- Drugs + alcohol
- Specific impairment increased
- Often more severe charges
## Two main types of statutes
**Per se laws (strict liability):**
- Specific drug presence = automatic violation
- No proof of impairment needed
- Common for THC (some states)
- Common for illegal drugs
- Specific to ${s.name}
**Impairment laws:**
- Must prove actual impairment
- Behavior + observations
- Less mechanical
- More common for prescription drugs
**Zero tolerance for some substances:**
- Any detectable amount
- Specific to substance
- Strictest enforcement
## Marijuana DUI specifics
**Major recent issue:**
**Per se THC limits:**
- Some states: 5ng/ml THC blood
- Limited science behind limit
- Frequent users may exceed without impairment
- Significant legal challenges
**Active vs metabolic THC:**
- Delta-9 THC (active, impairing)
- 11-Hydroxy-THC (active metabolite)
- Carboxy-THC (inactive metabolite)
- Different testing approaches
**Detection windows:**
- THC: hours after use
- Metabolic THC: days to weeks
- Inactive THC: weeks to months (heavy users)
- Specific to use pattern
**Legal use defense:**
- Medical / recreational marijuana
- Doesn't excuse impaired driving
- Specific legal issues
- Major defense in legal-state cases
## Detection methods
**Field assessment:**
- Drug Recognition Expert (DRE) evaluation
- Specific 12-step protocol
- Specific signs assessment
- Subjective evaluation
**Field sobriety tests:**
- Designed for alcohol
- Less reliable for drugs
- Specific limitations
- Limited evidentiary value
**Chemical tests:**
**Blood test:**
- Most accurate
- Most invasive
- Birchfield warrant requirement
- Specific procedures
- Specific drug panels
**Urine test:**
- Less common
- Detects metabolites
- Often inconclusive on impairment
- Specific procedures
**Saliva / oral fluid:**
- Increasing use
- Roadside detection
- Specific accuracy
- Specific procedures
**Hair test:**
- Long history
- Not used for impairment
- Specific to long-term use
## Drug Recognition Experts (DRE)
**Specially-trained officers:**
**Training:**
- IACP-certified
- 16-month program
- Specific protocols
- Court qualification
**12-step DRE evaluation:**
1. Breath alcohol test
2. Interview arresting officer
3. Preliminary examination + first pulse
4. Eye examinations
5. Divided attention tests
6. Vital signs + second pulse
7. Dark room exam (pupils)
8. Muscle tone + injection sites
9. Third pulse + statements
10. Opinion of officer
11. Toxicology
12. Final report
**Reliability disputes:**
- Frequent expert challenges
- Specific protocols
- Specific evidence challenges
## Penalties
**Generally similar to alcohol DUI:**
**First offense:**
- Misdemeanor typically
- Up to 1 year jail
- Fines
- License suspension
- Probation
- Treatment
**Repeat / aggravated:**
- Felony possible
- Specific enhancements
- Mandatory minimums
**Drugged DUI causing injury:**
- Same as alcohol DUI causing injury
- Felony
- Significant prison time
- See DUI causing injury guide
**${s.name}-specific penalties:**
- Specific to ${s.name}
- Specific provisions
- Specific to substance
- Specific aggravating factors
## Defenses
**Substance-specific:**
**Prescription medication:**
- Legal use
- Therapeutic dose
- Specific defense (varies)
- Some states allow
- Specific factual issues
**Marijuana:**
- Per se limits questioning
- THC science challenges
- Active vs metabolic challenges
- Long detection windows
- Specific scientific challenges
**Procedural:**
- Stop legality
- Search legality
- Birchfield issues (blood test warrants)
- Specific procedures
**Scientific:**
- Test reliability
- Chain of custody
- Specific lab procedures
- Calibration
- Cross-contamination
- Standards used
**DRE challenges:**
- Subjective opinions
- Specific protocols followed?
- Officer qualifications
- Specific factual issues
**Causation:**
- Drugs detected ≠ impairment
- Specific dose-response
- Long detection windows
- Inactive metabolites
## Combined alcohol + drugs
**Often charged separately:**
- Alcohol DUI
- Drug DUI
- Combined DUI (in some states)
- Multiple counts
- Sentence enhancements
**Synergistic effect:**
- Even smaller amounts impair
- Specific scientific issues
- Standard charges
- Significant penalty enhancement
## Legal medication issues
**Defenses available:**
- Prescription evidence
- Therapeutic dose evidence
- Doctor recommendations
- Specific medical use
- ADA accommodations
**Limitations:**
- Doesn't excuse actual impairment
- Mixed reception in courts
- Specific to ${s.name}
- Specific to drug
## CDL drivers + drugs
**Special rules:**
- Federal Motor Carrier regulations
- DOT drug testing
- Specific prohibited substances
- Specific limits
- See CDL DUI guide
## Implied consent + drugs
**${s.name} implied consent:**
- Generally covers drug testing
- Birchfield blood test warrant
- Specific procedures
- Refusal consequences
**Refusal:**
- License suspension
- Used as evidence
- Specific to substance
- Specific consequences
## Strategic considerations
**For defendants:**
- Hire experienced DUI / DUID attorney
- Specific drug-related experience
- Document medical use
- Preserve evidence
- Don't talk to police
- Don't refuse counsel
- Specific to ${s.name}
**Specific defenses:**
- Stop legality
- Test reliability
- DRE qualification
- Specific to substance
- Procedural issues
- Scientific challenges
## Recent trends
**Major issues:**
**Marijuana legalization:**
- More DUID cases
- Per se limits questioned
- Scientific challenges
- Specific to legal-state
**Opioid crisis:**
- More prescription drug DUIs
- Specific issues
- Treatment approach
- Specific to circumstances
**Detection technology:**
- Roadside oral fluid testing
- Specific accuracy improvements
- Legal challenges
- Specific to jurisdiction
**Per se law disputes:**
- Constitutional challenges
- Specific to ${s.name}
- Specific scientific basis
- Specific litigation
## What you should do
If charged with drugged DUI in Missouri: hire DUI attorney with DUID experience IMMEDIATELY. Missouri laws differ significantly from alcohol DUI. DRE evaluations + lab tests have specific challenges. Most Missouri DUI attorneys handle DUID. Specific specialists exist. Marijuana cases especially complex.
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*This guide is general information about Missouri law as of mid-2026 and is not legal advice. DUID cases are technical + scientific. Talk to a licensed Missouri DUI attorney about your specific situation.*
This guide is for general information only and does not constitute legal advice. Laws change and outcomes depend on your specific situation — talk to a licensed attorney before acting on anything you read here.