PHOENIX — A prosecutor argued Tuesday there’s nothing wrong with charging a motorist who smoked marijuana up to a month earlier with driving while drugged.
In arguments to the Arizona Supreme Court, Susan Luder, a deputy Maricopa County attorney, acknowledged that Carboxy-THC, a secondary metabolite of marijuana, can show up in blood tests for a month after someone has used the drug. And she did not dispute the concession of her own expert witness that the presence of that metabolite does not indicate someone is impaired.
But Luder told the justices 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.
Chief Justice Rebecca Berch questioned how far that logic can be stretched, asking Luder whether her argument falls apart if it turns out that Carboxy-THC can be measured a year, or even five years, after someone smoked the drug.
Luder said she understands arguments about why it may not be fair to charge someone 30 days later, “But that’s up to the Legislature to decide,” she said.
Justice Robert Brutinel also questioned where the line is drawn. He said some otherwise illegal drugs eventually metabolize all the way down to water.
“Where do you draw the line to when the metabolite’s no longer illegal?” he asked.
“It’s hard to say,” Luder responded.
The court ruling affects whether any of the 40,000 Arizonans who are legal medical marijuana users will effectively be banned from driving, given how long metabolite remains in the system. 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.
The immediate court case involves a driver cited for a traffic violation who, when 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.
A trial judge threw out the charge. But the Court of Appeals said the laws on impaired driving “must be interpreted broadly.”
Attorney Michael Alarid said that ruling effectively bans driving by anyone with the slightest amount of Carboxy-THC in the blood, “which is an absurd result.”
But Justice Scott Bales said the fact remains that anyone who tests positive for that drug had, in fact, used marijuana. And he said there is no way for police to “extrapolate backwards” to determine exactly when that person was impaired.
“If we don’t know that, wouldn’t it be reasonable for the Legislature to prohibit driving while you have Carboxy-THC in your system?” Bales asked.
Bales acknowledged some people who test positive for Carboxy-THC never drove when they were impaired. But he said, “if it’s a choice between erring on over-inclusive or under-inclusive, why isn’t that ... a policy question for the Legislature rather than one for us?’’
Alarid, however, said the only issue is whether there is specific evidence of impairment while someone is driving, which police could determine.
A simple ban on driving with Carboxy-THC in the blood is not rationally related to the purpose of the statute, which is to protect the public from “impaired’’ drivers, he said.
The justices gave no indication when they will rule.