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Arizona’s Highest Court Resolves Questions regarding DUI Convictions of Medical Marijuana Users (Dobson v. McClennen, 238 Ariz. 389 (2015))

Posted On: June 14, 2016 by Marc Neff

The two petitioners were each charged with and convicted of two counts of driving under the influence:  first, driving while impaired to the slightest degree under ARS Sec. 28-1381(A)(1); and second, driving while any amount of an impermissible drug or its metabolite is in the body under ARS Sec. 28-1381(A)(3) (emphasis added). Arizona’s DUI laws identify these as separate offenses. The trial court denied their motions to present their state-issued medical marijuana cards as evidence. The state dismissed the (A)(1) impairment charge, but both were convicted of the (A)(3) impermissible drug charge.

Petitioners appealed to the Maricopa County Superior Court, which affirmed the convictions. They then sought special action review in the court of appeals. The court denied relief, holding that neither ARS Sec. 36-2811(B) nor Sec. 36-2802(D) provides immunity for defendants facing charges for driving with an impermissible drug or its metabolite under (A)(3). The Supreme Court of Arizona granted review because the issue of whether the Arizona Medical Marijuana Act (AMMA) immunizes a registered patient from an (A)(3) DUI conviction is a recurring one in Arizona. The availability of an affirmative defense was also at issue.

After reviewing questions of statutory interpretation de novo and determining that neither position urged by the parties represented the best reading of the provisions, the court found that:

  • A registered patient may be convicted of an (A)(3) violation if the state proves beyond a reasonable doubt that the patient, while driving, had marijuana (or its metabolite) in his/her body
  • The patient may establish an affirmative defense under Sec. 36-2802(D) by:

—  showing that his/her use was AMMA authorized (subject to rebuttable presumption); and
—  the marijuana/metabolite was in a concentration insufficient to cause impairment

  • The patient must prove the insufficiency of the concentration by a preponderance of the evidence.

In this case, the petitioners made no effort to show that the marijuana concentration was insufficient to cause impairment. They relied on their argument that the AMMA categorically barred the (A)(3) charge and offered only their registry cards into evidence (although the cards would be admissible to invoke the presumption that the patient’s use was AMMA authorized). The court also found that any error by the trial court in excluding the petitioners’ registry cards was harmless.  The Court of Appeals opinion was vacated and the convictions affirmed.


–Registered qualifying medical marijuana users are not immune from a DUI charge.

–Any amount of marijuana in the user-driver’s body is enough for a charge and conviction.

–The user-driver has an affirmative defense: s/he must prove by a preponderance of the evidence that the amount was not enough to cause impairment.

–The affirmative defense may be challenging in reality as “there is no generally applicable concentration that can be identified as an indicator of impairment for illegal drugs.” State ex rel. Montgomery v. Harris, 234 Ariz. 343, 347 (2014). Nevertheless, this court stated that this risk of uncertainty “should fall on the patients, who generally know or should know if they are impaired and can control when they drive.”

–Expert witness testimony may be required.

For more than twenty-five years, the Law Offices of Marc Neff has been defending the rights of individuals and corporations facing serious criminal charges. Throughout Pennsylvania, New Jersey, and elsewhere, Mr. Neff has successfully defended clients charged with white-collar crimes such as mail fraud and bank fraud, RICO, drug distribution, money laundering, sex crimes and other serious offenses.

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Posted in: Driving under the influence (DUI), Drug Crimes