A New Defense for Driving Under the Influence of Marijuana? By Andrew Mishlove on May 13, 2014

drugged driving in WisconsinThe state of Wisconsin now permits a limited group of individuals to smoke marijuana, a potentially intoxicating substance, for medicinal purposes. For the rest of marijuana users in Wisconsin, possession of the drug could result in a maximum fine of up to $1,000 and six months in jail for first time users and steeper penalties for subsequent offenses.

Especially on the heels of new legislation legalizing some uses of medical marijuana, Wisconsin residents are increasingly wondering what the penalties are for smoking marijuana then operating a motor vehicle.

The state law prohibits drugged driving in two scenarios. First, it prohibits driving while under the influence of an intoxicant to the extent that the driver is incapable of driving safely. Second, the law prohibits driving with any non-prescribed controlled substance in the driver’s blood stream regardless of whether or not the driver appears physically impaired.

Under the second prong of Wisconsin’s drugged driving statute, it seems that a person can be convicted of drugged driving for merely having traces of marijuana in her blood stream even if she does not show signs of impairment from the drug at the time of arrest. However, a recent legal decision from the Arizona State Supreme Court brought about a different reading of drugged driving law that may have implications for some non-impaired marijuana users in states such as Wisconsin.

Marijuana Metabolism 101:

In order to understand the Arizona drugged driving case, it is helpful to have a basic understanding of how marijuana is metabolized. When marijuana’s tetrahydrocannabinol (“THC”) is taken into the bloodstream by smoking or oral ingestion, the body metabolizes it into byproducts called metabolites. One of the most common metabolites is Hydroxy-Tetrahydrocannabinol (H-THC), which may be found in the bloodstream when the user is impaired from the drug. A marijuana user then processes H-THC into secondary metabolites such as Carboxy-Tetrahydrocannabinol (C-THC), which may remain in the bloodstream for several weeks after the marijuana is first ingested. State-administered drug tests typically look for C-THC.

Arizona Drugged Driving Case: In the case before the Arizona Supreme Court, the defendant was accused of drugged driving after, upon arrest, his blood test revealed trace amounts of THC-C in his bloodstream. The defendant sought to draw a distinction between the type of marijuana metabolite found in his blood, THC-C, and the type of marijuana metabolite that is typically found in the bloodstreams of recent, impaired users, THC-H. The defendant argued that the Arizona legislatures did not intend to punish a person for having a stale trace of marijuana byproduct is his blood stream. Such a reading would not serve the legislator’s purpose of protecting Arizona’s residents from chemically impaired drivers.

The Arizona Supreme ultimately accepted the defendant’s argument and acquitted the defendant of the drugged driving charge. It also reasoned that the meaning of Arizona’s drugged driving statute was ambiguous and that criminalizing any trace of stale marijuana would lead to absurd results, such as criminalizing driving for a person who used marijuana five years ago or criminalizing driving by a person who had a marijuana byproduct in his system who did not illegally use marijuana.

Implications for Wisconsin Drivers:

So what does this Arizona case mean for some vehicle-driving marijuana users in Wisconsin?

At present, drugged driving in Wisconsin carries serious penalties such as suspension of driver’s license, substantial fines or imprisonment. The resolution of the Arizona case suggests that some marijuana users arrested for drugged driving for merely having marijuana in their system might be able to raise a defense to the charge based on the type of marijuana byproduct found in their system at the time of arrest.

If you or someone you know has been affected by a charge of driving a motor vehicle while under the influence of marijuana, contact an experienced OWI lawyer at Mishlove and Stuckert in Milwaukee, Wisconsin for a more thorough analysis of your case.


* PDF download of the Arizona Supreme Court Ruling

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