Driving Under the Influence of Marijuana
February 18th, 2014
The NY Times reports that most people who drive under the influence of marijuana, if stopped and tested, will pass the standard field sobriety tests. The articles reports: "In a 2012 study published in the journal Psychopharmacology, only 30 percent of people under the influence of THC, the active ingredient in marijuana, failed the field test."
So if that is true, what are the dangers of driving under the influence of marijuana?
The science, as summarized in the article, is hardly persuasive, since some studies show that stoned drivers tend to have less accidents than "sober" drivers.
The scientific debate may go on, but it is very clear that driving under the influence of marijuana is highly dangerous - to your driver's license.
Marijuana DWI Arrests on the Rise
I have seen an increasing number of arrests and prosecutions for driving under the influence of marijuana. It seems that there are more and more people who don't drive after drinking, or perhaps don't drink at all, but will drive after smoking marijuana (or, as is often the case, while smoking marijuana!).
Typically (but not always), these drivers do fairly well on the field sobriety tests. However, when arrested and asked to take a blood test (breath tests can't detect drugs only alcohol), these drivers face a difficult dilemma.
Drivers who Refuse the Blood Test
In NH, if driver under arrest for DWI-Marijuana refuses the blood test, he or she faces a 6 month administrative suspension. In the hearing regarding the administrative suspension, the prosecution has to show only that the officer had reasonable grounds to believe that driver was under the influence of some substance. The officer doesn't have to pinpoint that substance as marijuana, or even as a controlled substance. Since 2013, a DWI arrest can be premised on driver's impairment being caused by ANY substance, even something purchased over-the-counter, and the prosecution doesn't have to identify the substance, only the existence of impairment.
The good news, however, is that without a blood test, and as long as driver doesn't say too much about what she has been doing that evening, it is very difficult for the government to prevail in a DWI-drug case. In my experience, many DWI-marijuana clients who refuse the blood test end up with no DWI conviction, even if they do often have to suffer through the administrative suspension.
Drivers who Submit to the Blood Test
After being warned about the administrative suspension, many of my DWI-marijuana clients opt to submit to the blood test. At that point, they have escaped any possibility of an administrative suspension. However, they may have greatly increased the likelihood of a conviction. Why?
No Legal Limit for Marijuana Impairment in NH
First of all, in NH there is no "legal limit" for THC concentrations in the bloodstream. That means that there is no administrative suspension for a positive THC test. With alcohol, by contrast, a blood test at or over .08% blood alcohol concentration will result in a 6 month administrative suspension, just like a test refusal.
However, the lack of a "legal limit" also opens the door for the government to argue that any positive THC level is proof of guilt. In NH, the prosecution will often call an expert witness, employed by the State of NH, who will opine that the facts of the case as a whole - including the THC level - lead the expert to believe that the driver was impaired. If the case is tried to a Judge who already has a "zero tolerance" mindset for driving after smoking marijuana, a positive blood test can be a big boost for the prosecution. On the other hand, in my experience, many NH judges are very skeptical of DWI prosecutions premised upon low levels of THC in the bloodstream and little other evidence of impairment.
License Suspensions Reserved for the Innocent?
If you've been following this story you may have noticed that when we don't know what's in driver's bloodstream - when driver refuses a test - the likelihood of administrative suspension is substantial. When we do know precisely what is in driver's bloodstream - when stoned driver submits to the blood test - the likelihood of administrative suspension is zero. That's the way we do things in NH!
Why No Legal Limit for Marijuana Impairment?
Why is there no "legal limit" for THC in NH? The first problem is that there is no scientific consensus on where to set that limit. All experts, including the ones employed by the State, will acknowledge that every person reacts to drugs differently, and every person has a different level of drug "sensitivity" that will affect whether a given THC level has an impairing effect on that person.
The second problem is that for casual smokers (who are probably more impaired by marijuana), the psychoactive THC, referred to as delta 9-tetrahydrocannabinol, gets metabolized and leaves the blood stream very quickly, such that levels may be negligible within a very short time (e.g., only 1-2 ng/ml, while the driver still feels high). Daily users, by contrast, build up this compound in their fatty cells, such that medical marijuana patient and Denver News reporter William Breathes remained abstinent from marijuana for 15 hours and STILL tested positive at a 13.5 ng/ml level. Thus, the novice user, who is more high than the average user, has an "exculpatory" blood alcohol level, while the frequent user, who is 100% sober, has an "inculpatory" level. This is going to be more and more of a problem, now that medical marijuana has been legalized (but not yet available) in NH.
Marijuana Metabolites are No Fun
Incidentally, delta-9-tetrahydrocannabinol, the psychoactive compound, is "metabolized" (broken down) into a non-psychoactive byproduct, Delta-9 Carboxy THC. This is the substance that remains in the body for days or even weeks (and gets the Cumberland Farms employee fired for a positive drug test even though the employee isn't high, hadn't smoked on duty and hadn't touched marijuana for days). In NH, and unlike in other States such as Pennsylvania, a DWI prosecution cannot be premised on the presence of this non-psychoactive metabolite of THC in the bloodstream.
So, the moral of the story is simple. Even if you are a safe driver while stoned, mixing driving and marijuana is hazardous to your driver's license.