A ruling by the Arizona Supreme Court means the state can no longer prosecute motorists for driving under the influence of marijuana unless they were impaired when they were pulled over.
The ruling is a key victory for weed proponents and civil libertarians, who worried authorities would send innocent drivers to jail under Arizona’s stringent drugged-driving law.
States vary in how they treat drivers who use cannabis. Some require proof that the driver was actually impaired. Others apply a “per se” approach similar to the .08 limit used in drunk driving cases: A maximum level is set for marijuana metabolites in the bloodstream, and results above that number are evidence of guilt.
Still others have zero tolerance laws. This means a driver caught with any amount of weed in his or her system, no matter how little, is guilty. In just eight states, including Arizona, that includes inactive metabolites that don’t cause impairment.
This is especially critical to patients who use pot regularly because in heavy users the inactive metabolites in cannabis can linger in the bloodstream for weeks.
Arizona is one of 21 states with full-fledged medical marijuana. Voters narrowly approved it in 2010. Another five states have adopted limited MMJ designed mostly to help children with severe epilepsy. And two, Colorado and Washington, have legalized all pot for adults over 21.
The court’s ruling in Arizona removed a threat by prosecutors against all medical weed patients. Some said any patients who used should expect to be arrested if they drove; patient advocates said this was just a way of recriminalizing MMJ.
Now, prosecutors can no longer argue that the presence of inactive metabolites is proof of impairment under the drugged driving statute. They must show a driver was actually impaired – that he or she was driving erratically, for example.
The Arizona Supreme Court isn’t the first to limit a marijuana driving law. In 2013 the Michigan Supreme Court ruled police must have evidence a driver is actually “under the influence,” or impaired, before seeking charges.
The case in Arizona started when police stopped a resident for speeding. He later admitted he’d smoked pot the night before. He was tested, and the results showed inactive metabolites in his blood.
Arizona’s drugged driving law doesn’t make a distinction between active and inactive metabolites. So prosecutors charged the man with driving under the influence of a drug and operating a vehicle with the presence of marijuana metabolites in his system.
In court, they insisted the legislature intentionally left the definition of metabolite vague so it would cover all of the chemicals, whether or not they affect driving abilities. The state Supreme Court disagreed, saying that approach “leads to absurd results.”
“Most notably, this interpretation would create criminal liability regardless of how long the metabolite remains in the driver’s system or whether it has any impairing effect.”