Arizona Court Rules THC Metabolites Alone Cannot Justify License Suspension

LOS ANGELES- The Arizona Court of Appeals has ruled that the presence of THC metabolites in a driver’s bloodstream is not sufficient grounds for suspending their driver’s license unless the driver is shown to be impaired. This decision, made in the case of Aaron Kirsten, upholds provisions in the 2020 voter-approved cannabis legalization law, Proposition 207.

Kirsten was pulled over in Sedona in October 2022 for speeding, and officers noted signs of impairment such as bloodshot eyes and slurred speech. However, while his initial breathalyzer test showed a blood alcohol content (BAC) slightly above the legal limit, a more detailed test revealed a BAC of 0.063, below the legal threshold of 0.08. Additionally, a blood test detected THC metabolites, leading the Arizona Department of Transportation (ADOT) to suspend his license for 90 days.

Kirsten appealed the suspension, arguing that he was not impaired by THC at the time of his arrest and that THC metabolites can remain in the bloodstream long after cannabis use. The Court of Appeals agreed, stating that under Arizona law, the state can only penalize drivers for cannabis use if they are impaired “to the slightest degree” while driving.

The ruling clarifies the limitations of the state’s authority under Proposition 207, which legalized recreational cannabis use. According to the court, driving is a privilege, and the state cannot suspend driving privileges solely due to the presence of THC metabolites without proving impairment.

This decision marks the first appellate court interpretation of Proposition 207’s protections for cannabis users and limits the ability of state agencies like the Motor Vehicle Division (MVD) to suspend licenses based solely on THC metabolite levels.