The New Ruling Helps DUI Law in Arizona to Comport with Common Sense
Because the purpose behind Arizona's DUI laws is to protect against drivers whose ability to drive is impaired, the Arizona Supreme Court held in a ruling on April 22, 2014 that the metabolite that is prohibited under the current DUI law must be one that is capable of causing impairment in order for a person to be prosecuted for DUI.
Under current Arizona DUI law, a person can be prosecuted for:
(1) Driving while their ability to drive is impaired as a result of alcohol, drugs or a combination;
(2) Driving within two hours of having a Blood Alcohol Level above a prescribed limit; or
(3) Driving while they have a controlled substance or the metabolite of a controlled substance in their system1.
When a person's body metabolizes or breaks down a substance, the substance is broken into by-products or metabolites. Marijuana is first broken down into Hydroxy-THC which will then be broken down into Carboxy-THC. While Hydroxy-THC is an "active" metabolite and can be "impairing," Carboxy-THC is "inactive" and is not "impairing."
Carboxy THC can continue to be present and show up in a person's system for days, weeks or even up to a month after a person ingested marijuana even though it will have no impairing effect on that person. In the past, the police, prosecutors, courts and juries did not distinguish between people who drove with marijuana metabolites that were in fact capable of causing impairment from those who drove with metabolites that could not under any circumstances have caused impairment in DUI prosecutions. That has now changed as a result of the Arizona Supreme Court's decision in State v. Harris, opinion filed April 22, 2014.
Finally, some common sense breathed into a least a portion of the marijuana DUI legislation in Arizona.
1If the person has a valid prescription for the controlled substance and the amount of the controlled substance found in their system is consistent with a therapeutic range, the prescription can be a defense to (3) above only. A medical marijuana card is not currently considered a prescription by most judges and is therefore not even admissible according to many of those judges to explain the presence of marijuana in a person's system. That is still fodder for future litigation.