Medical Marijuana Cardholders And DUI In Arizona

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Since Proposition 203 – the Arizona Medical Marijuana Act – became state law in 2010, more than 80,000 people have sought and obtained medical marijuana cards in the state of Arizona. However, if you are suspected of marijuana-DUI in Arizona, a medical marijuana card will not keep you from being charged with driving under the influence, but it may be used as a defense if your DUI case goes to a jury trial. That’s what the Arizona Supreme Court ruled in November, and here’s why. Arizona’s Supreme Court ruled that medical marijuana card holders do not have any “blanket” immunity from prosecution under Arizona’s DUI laws. The current state laws prohibit motorists from driving while under the influence of marijuana or from even having in the bloodstream any amount of the active chemical component in marijuana, a compound called tetrahydrocannabinol or simply “THC.” But in its unanimous ruling, Arizona’s Supreme Court also gave medical marijuana card holders a new defense in DUI cases. If a medical marijuana card holder can “prove” to a court that he or she was not impaired while behind the wheel, the card holder cannot be convicted of driving under the influence.

Exactly how will that work? The first consideration is the chemical differences between alcohol and marijuana. Alcohol is water-soluble, so it leaves the bloodstream in just hours, but marijuana is fat-soluble and may remain in the system long after the user’s high has faded. Unlike alcohol, traces of THC can remain in a user’s bloodstream for days – sometimes even weeks – after the intoxication wears off. Because medical marijuana card holders use pot regularly, most card holders will have some trace of THC in their blood most of the time – whether or not they are actually “stoned” at any given moment. Prior to the November decision, medical marijuana card holders who drive were risking a DUI conviction. The state high court’s decision says card holders can try to show in court that even with THC in their blood, they were not under its influence while driving. The ruling overturned a lower court decision that made the presence of THC the key legal issue rather than intoxication and the impaired driving it can cause.


Arizona is one of the 23 states in the U.S. that currently allow marijuana to be used legally for medical reasons. However, the Arizona high court’s November ruling puts the burden on the defendant to prove his or her innocence in marijuana-DUI cases. Other states are taking their own approaches. For example, in 2013, the Michigan Supreme Court ruled that medical marijuana patients do not violate that state’s DUI law unless the police can prove that the driver was actually driving while impaired at the moment of the traffic stop. Arizona actually has two DUI laws addressing marijuana. One of the laws directly and exclusively forbids driving while impaired, but the other law prohibits Arizona drivers from having any trace of THC in the bloodstream. That law still stands for those who smoke pot illegally in Arizona – those who are not medical marijuana card holders – and it does not offer card holders the same protection, for example, as Michigan’s law.

Arizona’s Supreme Court justices frankly acknowledged in their decision that there is no commonly accepted threshold regarding what concentrations of THC are sufficient to cause impairment. Chief Justice Scott Bales wrote in the opinion. “The risk of uncertainty in this regard should fall on the patients, who generally know or should know if they are impaired and can control when they drive, rather than on the members of the public whom they encounter on our streets.”

In the particular case considered by the Arizona Supreme Court, two defendants had been convicted of marijuana-DUI in Arizona municipal courts. The municipal courts did not permit the suspects to use their medical marijuana cards as a defense, so they appealed their convictions to the Maricopa County Superior Court and then to the Arizona Court of Appeals. Both of those courts upheld the municipal court convictions, so the defendants made their final appeal to the state’s highest court.

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In the November opinion, those DUI convictions were upheld by the Arizona Supreme Court. While offering future DUI suspects a possible defense, the court ruled that the marijuana card did not grant to card holders any blanket immunity. The suspects offered no evidence and in fact made no effort to prove that they were not driving while under the influence of marijuana. They simply asserted that the card alone should protect them from DUI prosecutions, and the state’s Supreme Court justices rejected that assertion. Defendants “made no effort to show that the marijuana in their bodies was in an insufficient concentration to cause impairment,” Chief Justice Bales wrote. However, the justices suggested no particular legal method or mechanism for medical marijuana card holders to prove their innocence at a trial. The justices did, however, open up a Pandora’s Box of legal questions and issues.

For example, frequent marijuana users – and presumably medical marijuana card holders – build up a physical tolerance to marijuana. The amount of marijuana that easily intoxicates one person may have no intoxicating effect whatever on another person. How can you prove a negative – that you are not intoxicated? At least one attorney interviewed by Tucson’s KVOA News 4 believes the Arizona Supreme Court’s ruling may be unconstitutional because it violates the presumption of innocence and reverses it. Under the ruling, a medical marijuana card holder charged with DUI is effectively presumed guilty until proven innocent. Nevertheless, as recently as 2014, the same Arizona Supreme Court said that to equate the mere presence of THC traces in the blood to impairment was, in the language of the opinion, “absurd.” It’s the equivalent of saying that if you drank a beer a week ago and you get into an accident, it happened because you were intoxicated.


Marijuana-DUI will without any doubt be a contentious point in the 2016 effort to legalize recreational marijuana use in the state of Arizona – the “Regulate Marijuana Like Alcohol” campaign. Barrett Marson, a spokesman for that campaign, told the Arizona Republic that the campaign has gathered about half of the number of signatures that are needed to put the initiative on the 2016 Arizona ballot. Speaking for Arizonans for Responsible Drug Policy, a group opposing the legalization of marijuana for recreational purposes in Arizona, spokeswoman Melissa DeLaney told the Arizona Republic that the ruling was a win for public safety.

But even if lawmakers and courts can decide on a THC “intoxication level” comparable to the 0.08 percent blood alcohol content level that’s the legal limit for alcohol, is the technology available to determine an individual’s “level” of marijuana intoxication? Not really. At least not yet. A large number of researchers and tech firms are now racing to develop an accurate, easy-to-use marijuana breathalyzer. As legalized recreational and medical marijuana consumption expands across the nation, local police agencies will be requiring tools to assess accurately the intoxication levels of marijuana-impaired drivers.

While it’s not difficult to detect the presence of THC in the blood, there is still no sure way – and no accurate device – to determine the amount of time THC has been in the blood or to determine a driver’s current level of impairment. For now, in the states where marijuana is legal for recreational consumption, the legal limit for a marijuana-DUI charge is five nanograms of THC per milliliter of blood. The problem is that a person could have five nanograms of THC per milliliter of blood in their system weeks after smoking pot. There is simply no quick, convenient, and accurate breath test to determine if a driver is or is not intoxicated on marijuana at any particular moment.

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Any Arizona DUI conviction can have serious consequences, so it’s vital for DUI defendants in this state to know and understand their legal rights and options. In the greater Phoenix area, a defendant should obtain the services of an experienced Phoenix DUI defense attorney. A conviction for a first DUI offense in Arizona could land you in jail for ten days and could cost you a fine of not less than $1,250. You may also be ordered to perform community service, to submit to alcohol and substance abuse education, screening, and/or treatment, and to install an ignition interlock device (IID) in your personal vehicle.

A second or subsequent DUI conviction in Arizona is punishable by up to ninety days in jail and by a fine of not less than $3,000. Your driver’s license will be revoked for a full year after a second DUI conviction in Arizona, an IID installation and community service will be ordered, and you will additionally be required to undergo extensive alcohol and substance abuse education, screening, and/or treatment. Interested in learning more about DUI laws or marijuana laws in the state of Arizona? Comment below or reach out to us on our social media channels, we’d love to hear from you. If you need legal help regarding a DUI matter, contact and speak with an experienced Phoenix DUI defense attorney today.

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