Courts Debate How To Measure DUI Related To Old Marijuana Use

November 06, 2013

The Arizona Supreme Court is being asked to decide if a motorist who may have smoked pot up to a month ago can be charged with and prosecuted for driving under the influence of drugs.

Under Arizona law, it is a crime to operate a motor vehicle with any amount of drugs or their metabolites in your body. One secondary metabolite of marijuana can remain in the blood for 30 days, but even an expert witness for the prosecution has acknowledged the chemical is not psychoactive. The state argues the Legislature can declare a positive blood test for Carboxy-THC by someone who has been driving is a crime.

Chief Justice Rebecca Berch wondered how far that logic can be stretched.

“Let's assume that scientific testing develops and now we discover that you can find Carbocy-THC remaining in the system for a year,” Berch said. “Does that have any effect on your position here today?”

Prosecutors said that is up to lawmakers to decide, but Berch continued to push.

“Let's now assume that it's five years you can test Carboxy-THC remaining in the system,” Berch said. “Does there come a point where the statute lacks a rational basis?”

Deputy Maricopa County prosecutor Susan Luder said maybe but would not concede the point saying it was not reality. The justices had equally difficult questions for the plaintiffs. They gave no indication when they would rule.