PA Court Rules Medical Marijuana Use Can Result in DUI Charges
Posted in DUI on June 20, 2025
In a landmark 2022 decision, the Pennsylvania Superior Court ruled that legal medical marijuana users can still be charged with DUI under state law—even without evidence of impairment. This case, Commonwealth v. Stone, clarified the legal conflict between Pennsylvania’s Medical Marijuana Act (MMA) and the state’s Driving Under the Influence (DUI) laws.
🚗 Case Background: Medical Marijuana and DUI Arrest
Defendant: River Garrett Stone
Charge: DUI under 75 Pa.C.S. § 3802(d)(1)(i)
Context: Stopped for speeding; admitted to being a medical marijuana patient; THC detected in blood test.
Defense: Argued that the Commonwealth must prove the THC was from non-medical marijuana.
Trial Court Ruling: Allowed jury instruction requiring proof of non-medical THC.
🧑⚖️ Key Legal Issue
Can a legal medical marijuana user in Pennsylvania be convicted of DUI based solely on the presence of THC in their system?
🏛️ Pennsylvania Superior Court Ruling
In Commonwealth v. Stone, the court reversed the trial court’s decision, holding:
Marijuana remains a Schedule I drug under Pennsylvania law—even for medical users.
The Medical Marijuana Act (MMA) does not reclassify marijuana or exempt users from DUI statutes.
The DUI law under § 3802(d)(1)(i) applies regardless of whether the marijuana was legally prescribed.
“The Commonwealth does not need to prove that the THC in a defendant’s blood came from non-medical marijuana to convict under Pennsylvania’s DUI statute.”
🔍 Legal Reasoning
MMA’s limitations: The MMA allows legal possession and use of medical marijuana but does not create an exception to DUI laws.
Strict liability: § 3802(d)(1) makes it a violation to drive with any Schedule I substance in your blood—impairment does not need to be proven.
Policy clarity: The court emphasized it is up to the legislature, not courts, to change marijuana’s classification or update DUI laws.
🚨 What This Means for Medical Marijuana Patients in PA
If you’re a registered medical marijuana user in Pennsylvania, here’s what you need to know:
✅ Legal use ≠ protection from DUI: Even if prescribed, THC in your system can lead to DUI charges.
🕒 THC can linger in your body long after impairment fades, and a person can be charged with a DUI based upon having THC metabolites in the body.
🔧 How This Affects Future DUI Cases in Pennsylvania
Courts will not permit jury instructions that require prosecutors to distinguish between medical vs. non-medical marijuana.
Expect more DUI convictions based on THC presence alone, regardless of medical authorization.
Defense strategies in marijuana DUI cases must focus on constitutional issues, such as due process or equal protection, rather than statutory exemptions.
📝 Final Thoughts: Legal Weed, Legal Risks
Commonwealth v. Stone sets a strong precedent: in Pennsylvania, medical marijuana and DUI laws are on a collision course, and for now, DUI laws win. Until marijuana is rescheduled under state law or the DUI statute is reformed, legal use can still result in criminal penalties.