Measuring marijuana intoxication in drivers has become more confusing since adult-use marijuana was legalized in Arizona.
But in a new ruling earlier this month from the Arizona Court of Appeals, the presence of THC in the bloodstream is no longer adequate evidence of DUI. Instead, the state must now provide proof of impairment as grounds for license suspension.
While critics of the court’s new ruling argue that there is now an implication that it is safe to drive while under the influence of marijuana, the crux of the matter is rooted in overall struggles in detecting marijuana impairment. Before the ruling, detecting marijuana in the bloodstream was enough evidence to warrant a DUI charge, regardless of when cannabis was consumed.
The ruling is connected to a DUI charge in Sedona in October 2022 brought to the Arizona Court of Appeals. According to court documents, the appellant was pulled over for speeding. It was early in the morning, and the officer noticed bloodshot eyes, and slurred speech. A breathalyzer test was issued, in which the appellant blew a 0.083, and refused a field sobriety test. Then he was arrested for driving under the influence.
However, after consenting to a blood test in police custody, results revealed that the appellant’s blood alcohol content was 0.063 less than what is permitted under Arizona law. His blood test detected tetrahydrocannabinol metabolites. Though the appellant claimed he had not consumed marijuana within the 24 hours leading up to his arrest, state law required the suspension of a driver's license for 90 days upon the detection of THC metabolites.
This is a tricky leg to stand on, as experts agree that cannabis can stay in the bloodstream anywhere from days to months. Similarly, Breathalyzer cannot detect the presence of marijuana. After the ruling was appealed to the Maricopa County Superior Court, the court was then tasked with understanding how the marijuana applied to state laws.
The court found that, due to two different provisions in Proposition 207, which legalized recreational marijuana in Arizona, the state was not allowed to suspend the appellant’s license solely based on finding THC metabolites in the bloodstream.
For one, court documents noted, Proposition 207, explicitly requires the state to suspend a license while driving impaired. However, under A.R.S 36-2852, which pertains to possession and personal use of marijuana, “the following acts by an individual who is at least 21 years of age are lawful, are not an offense under the laws of this state or any locality, may not constitute the basis for detention, search or arrest, and cannot serve as the sole basis for seizure or forfeiture of assets, for imposing penalties of any kind under the laws of this state or any locality or for abrogating or limiting any right or privilege conferred or protected by the laws of this state or any locality.”
Because Arizona law also views driving as a privilege, this is a privilege that is ultimately protected by Arizona’s cannabis laws.
Instead, law enforcement will be urged to acquire clear evidence of impairment, rather than relying on tactics that were designed for detecting alcohol intoxication.
