Prosecutor Argues Smoking Pot a Week—Even a Month—Before Driving Is Grounds for DUI

A ruling could mean Arizona’s 40,000 legal medical marijuana users would be banned from driving.

Photo Credit: Shutterstock.com/Couperfield

Smoking cannabis a week prior to driving a car is grounds for a DUI according to the argument of a prosecuting attorney in Maricopa County, Arizona on Tuesday.

An Arizona driver received a traffic citation and when given a blood test, was found to have carboxy THC—a metabolite in cannabis that is fat soluble, inert, and possess an relatively long detection window in blood and urine—in his system. A trial jury threw out the charge that the driver was "driving with an illegal drug or its metabolite" in his body. The Court of Appeals declared that laws on impaired driving “must be interpreted broadly,” and the case was reopened.

Despite the fact that the THC metabolite is proven to show up in blood tests for a whole month following use of cannabis, Susan Luder, a deputy attorney, made the argument to the Arizona Supreme Court that a THC metabolite positive blood test was legal grounds to prosecute for a DUI charge.


According to an article in the Arizona Daily Star, Luder’s own expert witness testified that the presence of THC does not mean a person is impaired—which Luder did not dispute.

As the Daily Star reported, the court’s chief justice, Rebecca Berch, as well as Justice Robert Brutinel questioned Luder’s logic. Luder acknowledged the argument that it may not be fair to charge someone long after their substance use. But, she said, “That’s up to the legislature to decide.”

A ruling is still pending, but if Luder’s logic is upheld and the driver convicted, he could lose his license for a year. The Daily Star article also points out the larger implications of the ruling, which could mean Arizona’s 40,000 legal medical marijuana users would be banned from driving altogether.

“[U]sers will effectively be banned from driving, given how long metabolite remains in the system,” the article reads. “And it also makes potential criminals out of anyone else who drives and also has used marijuana in the last 30 days, including those who might be visiting from Washington or Colorado, where recreational use of the drug is legal.”

Don't let big tech control what news you see. Get more stories like this in your inbox, every day.

April M. Short is a freelance writer who focuses on health, wellness and social justice. She previously worked as AlterNet's drugs and health editor.