By: Ashley Russo

On January 1, 2014, Colorado became the first place in the United States to legally sell marijuana to anybody over the age of 21 for any purpose. Soon after, Alaska, Nevada, Oregon, and Washington state opened up their own recreational dispensaries. While it is legal to purchase and use marijuana in these states, it is absolutely not legal to drive while under the influence. However, nearly four years later, scientists, law enforcement officials, and members of state legislatures have yet to develop a reliable field test for establishing whether or not one is actually driving under the influence of marijuana.

Police officers in these states are concerned with maintaining the safety of their roads. Since legalization, police officers throughout the country have participated in formal education seminars on marijuana. These programs teach officers how to identify various marijuana products and paraphernalia, and what to do when they pull over a driver that they suspect is under the influence of marijuana. Outside of states that have yet to legalize marijuana, police officers look to behavioral indicators to base their judgements on when determining if someone is driving under the influence of THC.

However, despite the increasing number of states that have either legalized marijuana, or that have taken steps towards legalization, no police officer has access to the equivalent of a reliable alcohol breathalyzer or blood test for marijuana. Although tests exist that can detect some of marijuana’s components, such as a blood test, there is no standardized amount of a chemical that can be detected in the breath or blood of a driver that can give the police or courts a decent sense of who is impaired.

Marijuana affects everyone differently, which is likely due to its main psychoactive chemical: delta-9-tetrahydrocannabinol, or THC. These can range from a dry mouth and red eyes to paranoia and anxiety. It can also cause feelings of euphoria, elation, and pain relief. With this, some police departments have started to use drug-recognition experts in the field that are specially trained to evaluate suspected drugged drivers. These experts look to the driver’s blood pressure and pulse while conducting eye exams, balance tests, and even performing tests on iPads, such as tracking an object on a screen or estimating an elapsed amount of time.

On the scientific front, scientists are working to create such a chemical test and a standard to apply to that test. However, it is proving to be very difficult for research to be done at the federal level for such a device. Federally, marijuana is a Schedule 1 substance, meaning that it is considered a drug that has no accepted medical use and has a high potential for abuse. This means that engineers or scientists living in Colorado, where marijuana is legal at a state level, and working in a federal lab, where marijuana is illegal are prevented from conducting research on the substance. This prevents these people from testing samples for research purposes, even from a purely scientific standpoint.

Currently, in states that have legalized the substance, THC blood tests do exist. These allow police officers to determine a permissible inference that someone was impaired by THC while driving a vehicle. For example, in Colorado, if a person has more than 5 nanograms of THC per milliliter of blood, a court or jury may find that they were impaired.

However, several experts in the field assert that the 5 nanogram of THC per milliliter of blood cutoff does not actually mean anything when determining if someone was high while driving. There is not enough research done to determine whether that threshold means that a person is still impaired or not. This means that currently, there is no quantitative measure that could stand in a court of law in issuing a driver a DUI charge for THC.

But, if marijuana is so difficult to detect, how have law enforcement officials been using breathalyzers to determine if someone was driving under the influence of alcohol for decades? Ethanol, the chemical in alcoholic drinks, is distributed fairly quickly throughout the body. Because humans are mostly water, ethanol is usually cleared from the body within a matter of hours. However, THC dissolves in fat. This means that THC has the ability to linger throughout the bodies of different people much more so than alcohol. Gender, body fat, frequency of use, and the method and type of marijuana used all influence how long THC stays in one’s body. Research studies at state levels have found that THC can stay in the blood of a marijuana-user for up to 30 days, even when abstaining from the drug for the month. In the same study, users who regularly used marijuana found that the THC levels in their blood remained above the 5 nanogram level for several days after they stopped using it.

Because of these inconsistencies in determining a driver’s THC level at the time of their arrest, a blood test is insufficient to establish that someone was intoxicated at the time of their arrest. With this, some scientists have attempted to search for an answer in establishing a threshold in breath. However, they are running into similar problems with this route – THC degrades very quickly on the breath and only appears in small amounts.

There are certain leads that scientists, some being experts in extracting small molecules, have in order to create a reliable THC breathalyzer. However, there is still a long way to go until a reliable threshold is created for establishing whether or not a person was intoxicated while operating a motor vehicle. Until then, police officers will have to continue to use behavioral queues to determine if someone was driving while high on marijuana.

Student Bio: Ashley is a current 3L at Suffolk University Law School. She is the Managing Editor of the Journal of High Technology Law and the President of the Suffolk Public Interest Law Group. She holds a B.A. in History and Political Science from Hobart and William Smith Colleges.

Disclaimer: The views expressed in this blog are the views of the author alone and do not represent the views of JHTL or Suffolk University Law School.


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