Marijuana “Breathalyzer” Development Progressing

In an article a few weeks ago from the National Institute of Standards and Technology, the groundwork for a reliable Marijuana breathalyzer was discussed. Since Marijuana is burgeoning more and more in society as an acceptable and medicinally useful substance, there’s been a larger push to establish reliable breathalyzers to determine if a person is too high to be driving. 28 states now allow either recreational or medicinal use and there’s a growing worry that this will cause more drivers to go out on the road under a heavy influence of Marijuana. As you can imagine though, it’s a lot more complicated accurately measuring how much someone is under the influence of marijuana than it is for alcohol. It’s also not like alcohol breathalyzers are some perfect thing either. They are by their design imperfect and have to be used in a very specific time frame to be effective and usable in court proceedings. So the fight to determine if someone is too high to drive is an uphill battle and i’m not even sure if it’s one worth fighting for. However, it seems scientists at NIST(where said article is from) have made a mini breakthrough according to this piece. “But scientists at the National Institute of Standards and Technology (NIST) have taken an important step toward that goal by measuring a fundamental physical property of the main psychoactive compound in marijuana, delta-9 tetrahydrocannabinol (THC). Specifically, they measured the vapor pressure of this compound—a measurement that, due to the compound’s chemical structure, is very difficult and has not been accomplished before. The results were published in Forensic Chemistry.” NIST left the link to those results so you may access them here as well. Tara Lovestead, the author of the study explains that vapor pressure “describes how a compound behaves when it transitions from a liquid to a gas. That’s what happens in your lungs when a molecule leaves the blood to be exhaled in your breath. So if you want to accurately measure blood levels based on breath, you need to know the vapor pressure.” Despite this little breakthrough there is still much more research needed to actually move forward with this reliable breathalyzer idea and there are more underlying questions that further complicate this crusade.

One concern the article mentions, is how do you determine if a person is too impaired by marijuana to drive? What level of being high makes a dangerous driver out on the road and what is the relationship between motor vehicle accidents and marijuana intoxication? Are those relationships direct or indirect? When does an officer have probable cause to use it? These questions have no easy answers at all. There are enormous complications in determining if being high makes you more likely for an accident which is the assumption under which a  breathalyzer would work. As with alcohol there is also a vast difference in people’s reactions to Marijuana based on a variety of different factors. Things like weight, age, amount of food consumed, prior experience in smoking all make a difference. An experienced marijuana consumer who say smokes a 1 gram blunt to themselves will very likely be in a less inebriated state than say someone who hasn’t smoked much if at all before and shares in on smoking a .5 gram bowl or blunt. So how do you deal with that variation? I think the fact that there are a vast amount of different Marijuana strains with differing effects also further complicates things. There are Indica strains- strains that are useful for relaxation, anxiety, insomnia, and pain relief. These are the ones generally used medically and they can cause sleepiness or disorientation depending on how much you consume. There are also a variety of strains of the Indica branch that again have differing effects. The relaxation type  strain is what I envision being more stigmatized when used for driving, because it’s purpose is to slow you down and usually make you tired.

Other strains like the  Sativa strains are useful for a more uplifting, energetic, or euphoric feeling and are also known to increase focus and creativity. Once again, there also many differing types under the Sativa branch. But I think you can see why this would be complicated if Sativa marijuana can actually make you more focused. I am skeptical a person high on a Sativa strain is a danger on the road at all or more dangerous than someone under a lesser influence of an Indica strain.

Also, people smoking Indica strains are logically going to be less likely to want to go out on the road and drive, since they’re probably going to be tired. There’s obviously exceptions to this but my point is that the people who I think would be more likely to be unsafe drivers under the influence of marijuana are more likely to stay off the road and the people who are more likely to go out on the road under the influence of weed are more likely to be safe drivers under that influence. That is speculation on my part but I think it makes logistical sense. Also these strains don’t just have differing effects but differing effectiveness. Smoking a little bit of a very powerful strain can make you very high while smoking a lot of a weaker cheaper strain might not even affect you that much.  So even though NIST is developing a technology called PLOT-cryo that could be better at measuring vapor pressure and therefore calibrating breathalyzers to a standard measurement, I’d still be skeptical whether it be effective in determining how much influence someone is under and whether that influence is actually affecting their driving ability. People shouldn’t be driving impaired but the logistics of this idea are very tough.


This is the opinion of Jake Morask and not Laura Law as a whole.

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