Arizona DUI Marijuana Law | Ventura DUI | David Lehr Law

Arizona Supreme Court Rules on Driving-Under-the-Influence Law for Marijuana Users

Arizona Supreme Court DUI Law for Marijuana Users

On April 22, 2014, the Arizona Supreme Court recently ruled that law enforcement can’t prosecute Arizona motorists for driving under the influence of marijuana unless the person is actually impaired at the time of the stop.

The Arizona Supreme Court justices rejected arguments made by the Maricopa County Attorney’s Office that a motorist whose blood contains a slight amount of the secondary metabolite Carboxy-THC, found in marijuana, can be presumed to be driving while impaired.  The Court stated that medical evidence shows that’s not the case.

This ruling immediately affects legal medical marijuana users in Arizona, who currently number more than 40,000.  It means that legal medical marijuana users will not be banned from driving regardless of how long the Carboxy-THC metabolite remains in the user’s blood.  This ruling also provides protection against impaired driving charges for anyone else who might have marijuana in their system, including those who might be visiting from other medical marijuana states, like California, or those who might be visiting from Washington or Colorado, where recreational use of marijuana is legal.Arizona Supreme Court | Ventura DUI | David Lehr Law

The case stems from a driver who, after being cited and given a blood test, was found to have Carboxy-THC in his system and was charged with driving with an illegal drug or its metabolite in his body.  While the trial judge dismissed the charge, an Arizona Court of Appeal said the laws on impaired driving “must be interpreted broadly.”

Susan Luder, a deputy Maricopa County attorney, told the justices that the Legislature is legally entitled to declare that a positive blood test for Carboxy-THC can be used to prosecute someone who, if convicted, can lose a driver’s license for a year.  Ms. Luder also acknowledged, however, that Carboxy-THC can show up in a user’s blood test a month after the marijuana was initially ingested.  Ms. Luder also did not dispute the concession of her own expert witness that the presence of the metabolite does not indicate that someone is impaired.

Thankfully, Justice Robert Brutinel, who authored the majority ruling, stated this argument makes no sense.  According to Justice Brutinel:

“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…if a metabolite could be detected five years after ingesting a proscribed drug, a driver who tested positive for trace elements of a non-impairing substance could be prosecuted.”

Justice Brutinel noted that even prosecutors contend the metabolite itself does not cause impairment.