Well, folks, it is finally here.  With the contemporary “reefer madness” showing no signs of slowing, the minds at Hound Labs, an Oakland based, scientific instrument research start-up, have recently released a marijuana breathalyzer machine!  Say what?!!  Yes, in all seriousness, this company states that it has developed a machine to detect marijuana use “within the last couple of hours,” similar to hand-held, portable breath testing devices that detect alcohol.  With alcohol, every state recognizes an alcohol limit of .08, except Utah, which lowered that level to .05 at the beginning of the year.  But with marijuana, that level is . . . uh . . . hey!  Brownies!

We, on the criminal defense bar, as well as many involved in the criminal justice system, have been wrestling with the complex and oftentimes perplexing quagmire that has been marijuana for nearly a decade.  Should it be legalized like alcohol?  Is it legal for medical use?  What constitutes medical use?  Who can get a certification (not a prescription) and for what?  How much can be legally possessed and consumed?  Is it safe to drive with a certification?  What is the difference between CBD and THC?  At what level is a person impaired?

The Arizona Supreme Court just recently heard arguments on a case that hopes to answer some of these questions, so be assured, we will keep you informed.  However, the law is notoriously slow to reflect and address changing public norms, and as “weed culture” pushes more and more into the mainstream with many states, from New York to Michigan, Colorado, and Nevada (to name a few) legalizing pot for recreational use, the legal field is scrambling to address safety concerns and now-outdated laws.

Although less commonly understood by lay persons, the law is clear that driving under the impairing influence of legal, illegal, or prescription drugs will land a person with a DUI.  One area of significant controversy and concern is driving under the influence of marijuana’s psychoactive chemical, THC, or its metabolite, Hydroxy-THC, both of which are considered to have “impairing” effects.  Studies about alcohol and its effects on a person’s cognitive or motor abilities are vast and seemingly never-ending and are the basis for the .08 legal limit.  Scientists agree: all persons will be impaired by alcohol for the task of driving if their blood alcohol concentration is a .08 or greater.  These studies were possible because of alcohol’s legal status with the federal government.  Marijuana, on the other hand, is still classified as a Schedule I drug according to the United States’s Controlled Substances Act.  Many, if not most, researchers are employed by public universities funded by federal grant money, but the universities are prohibited from conducting federally illegal activities . . . such as using marijuana.

So what’s the limit for marijuana—and why is that the limit?  Well, there isn’t an agreement among scientists (see above regarding not being able to conduct studies), so some states, like Colorado, have set arbitrary limits like 5ng of THC/mL of blood.  In Arizona, if the instruments can detect THC in your blood, you’re over the limit because no one is permitted to drive with active marijuana metabolites in his or her bloodstream.  But what if that miniscule amount isn’t actually impairing the person?  And how can someone even tell if a person is impaired “to the slightest degree” by marijuana?

Drug DUIs are understandably more complicated than alcohol DUIs because unlike alcohol, the issue, and many times legal controversy, around drug DUIs lies in the nature of the arrest by an officer who may or may not be a “certified drug recognition expert” who allegedly observes signs and symptoms of impairment.  These officers often rely on observing certain “cues,” a person’s physiological response to a stimulus or performance of a certain task.  Sure, these tests can indicate that something is amiss—but they cannot confirm or deny the presence of a specific drug in a person’s system, or that a drug is the cause of any physiological curiosities.  These field tests are used as an investigative tool—not definitive proof.  It is not until blood tests come back that any determination can be made regarding the presence of an impairing drug in the system at the time of the arrest.  So when it comes to a person suspected of driving while high, an arrest can be made without actually knowing whether or not that person has consumed marijuana and more importantly, whether or not that consumption impaired their ability to drive by the slightest degree.  Wowza.  Yet, marijuana DUI arrests happen all the time—arguably more now than ever—as more people take advantage of the legal green light to embrace their inner hippies.

“Well, that doesn’t seem fair! How can an officer arrest me for driving high if they have not proved that I have marijuana in my system?  These FST tests sound awfully arbitrary, and what, exactly, “qualifies” one to be a “Drug Recognition Expert?”  I bet there are racial disparities in the number of marijuana arrests, too.”  Hound Labs founder, emergency room physician and deputy sheriff Mike Lynn, was both angered and perplexed by these very questions, so he set out to develop the first breathalyzer to test for recent marijuana use, when a person is most likely to be impaired, by identifying marijuana on a person’s breath.  Lynn argues that his machine will help keep drivers safe and police more honest by providing a more concrete method of determining marijuana ingestion.  That sounds pretty good, right?  Well, don’t get too excited just yet.

According to research published in Trends in Molecular Medicine,  levels of THC do not line up in a “straightforward way” to levels of individual impairment.  Some people can be impaired at 1 nanogram per milliliter of blood, while others may show no signs of impairment at 5 nanograms.  There is much more yet to understand about the way THC interacts with the human body or about the other 500+ compounds found in marijuana and how the body reacts during different phases of absorption and elimination or break down.  Since THC is stored in fat cells (unlike alcohol) and can be released over time, it is extremely difficult to tell whether someone has smoked marijuana that day or a week or even a month ago—particularly if that person is a heavy user.

So while Lynn’s test boasts of being able to detect whether someone has marijuana on their breath—indicating that they may have recently smoked marijuana—it still cannot tell if someone is impaired due to the presence of that marijuana because of the complicated nature by which THC interacts with the body.  Nothing is mentioned, either, about the consumption of edibles, oils, or other forms of marijuana use (go into your local dispensary and you’re sure to find a Wonka-esq assortment of items).

No one has argued that marijuana does not, in fact, impair the cognitive or motor functions needed for safely operating a motor vehicle, but research has shown that there is not yet  scientific agreement to establish a standardized legal limit for THC levels.  It seems Lynn’s machine may only be able to confirm or deny the presence of marijuana—which is better than deciding that someone has ingested marijuana based on her ability to count backwards from 30 to 0 with her head tipped back and eyes closed.  The best practice, according to the article in Trends in Molecular Medicine, to determine impaired driving due to marijuana may still be pointing to specific driving behaviors coupled with a blood test confirming the presence of THC or its impairing metabolite in the system at some level.  We patiently await more research in this important area.  As for Lynn’s claims regarding keeping police honest and tackling racial profiling, we appreciate his efforts and admire his optimism.

Science clearly has a long way to go in catching up with the contemporary culture and the law further, still.  In the meantime, however you choose to indulge, be safe and contact an attorney to navigate through the tumultuous and ever-changing sea that is the marijuana DUI.