Marijuana Reclassification | Judge Mary Celeste (Ret.)
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Judge Mary Celeste (Ret.) | Denver, CO Facebook Twitter LinkedIn 2016 Best Legal Blog Nominee
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The Impact of the Gerhardt Decision on Marijuana Driving Case

One of the major consequences of legalizing marijuana is that it can affect drivers on the roadways. Courts across the country are facing issues such as the applicability of the long established standard field sobriety test for alcohol-driving impairment to determine marijuana-driving impairment; the characteristics indicative of marijuana-driving impairment; and the blood nanogram concentration levels that establish marijuana-driving impairment. The Massachusetts Supreme Court was the first state Supreme Court out of the box to address these issues.


On January 6, 2017, the Massachusetts Supreme Court heard oral arguments in the case of Commonwealth v. Gerhardt1, which required the court to consider several novel


• What physical characteristics (e.g., bloodshot eyes, dilated pupils, lack of coordination, slow balance or reaction times, garbled or slow speech) permit an inference of impaired driving by reason of marijuana use?

• Is there a scientifically established correlation between performances on field sobriety tests and marijuana-impaired driving?

• Is there a level of intoxication that is generally accepted as establishing impairment as to driving?


• Has any jurisdiction, foreign or domestic, recognized such a level of intoxication?


As far as marijuana-driving cases go, the facts of the Gerhardt  case were not unusual. The defendant (Gerhardt) was stopped for driving without working tail lights. Once stopped, an officer saw smoke inside the vehicle and detected the odor of marijuana. The defendant stated that he had smoked around three hours before the stop, although another passenger said it had only been 20 minutes. Gerhardt pulled two marijuana cigarettes (“roaches”) from an ashtray and handed them to the officer. In a subsequent search, officers found two more roaches.


As more and more marijuana-driving cases come forward, the plain view doctrine will play a large role. The plain-view doctrine has been expanded to include plain feel, plain smell, and plain hearing.4 The U.S. Supreme Court agrees that the smell of marijuana may provide probable cause to obtain a search warrant.5 Further, some state courts hold that detection of the odor of marijuana or marijuana smoke provides probable cause for a warrantless search.6 Oddly enough, searches based upon marijuana smell have decreased in the states of Colorado and Washington, which were two of the first states to legalize recreational marijuana.


All of the facts related to the Gerhardt stop established probable cause to request that he perform a standard field sobriety test and Gerhardt consented. He failed several tests:


        Rather than standing heel to toe, with his right foot infront and his left toes touching his heel, as he had been shown, Gerhardt moved his feet so that they were side by side; he also did not turn around as instructed . . . Gerhard[t] did not remain upright on one foot, instead

putting his foot down multiple times, and swayed. It should be noted that counting backwards and reciting the alphabet, although frequently used by law enforcement in suspected driving-impairment stops, is not part of National Highway Traffic Safety Administration sanctioned alcohol field sobriety tests.


       For purposes of alcohol impairment, a standard field sobriety test consists of the horizontal gaze nystagmus, the one-leg stand, and the walk-and-turn.9 For purposes of detecting drug impairment, sometimes the Romberg or modified Romberg test is added:


       [T]he officer will ask you to stand with your feet together, head tilted slightly back and eyes closed. You will be asked to estimate when 30 seconds has passed, and say “stop” when you think it’s been that long. While you are balancing, the officer will look for six clues: amount and direction of swaying, eyelid/body tremors, estimate of when 30 seconds has passed, muscle

tone, sounds or statements made during the test, ability to follow directions.


Some research says that standard field sobriety tests are effective in identifying marijuana-driving impairment, some research says that they are only moderately successful, while other research says that only the walk-and-turn or the one-leg stand tests are effective. One study stated that the finger-to-nose test was the best test to accurately predict cannabis impairment. Many agree, however, that the horizontal gaze nystagmus test is not effective.


Indicators of marijuana-driving impairment include eyelid tremors, increased pulse, elevated systolic blood pressure, dilated pupil size, lane weaving, driving on the wrong side of the road, drifting, following too close, driving a large distance from the vehicle ahead, not responding to questions, reddened eyes, slow pupil reaction, nervousness, laughing, and unusual facial expressions. Some believe that one side effect includes “green tongue,” although the appellate courts in both Utah and Washington are skeptical.


Studies and reports from 2004 through 2012 designated THC blood concentration levels from 2 to as high as 30 THC ng/ml as establishing marijuana-driving impairment. The more recent studies and reports, however, do not support the designation of a blood nanogram concentration level as the sole indicator of marijuana-driving impairment. The July 2017 National Highway Traffic Safety Administration Marijuana-Impaired Driving Report to Congress stated that there is a “poor correlation of THC concentrations in the blood with impairment”

and that “setting per se levels is not meaningful.” In 2016 the AAA Traffic Safety  Administration also stated that “it is difficult to establish a relationship between a person’s THC blood or plasma concentration and performance impairing effects. Concentrations of parent

drug and metabolite are very dependent on pattern of use as well as dose. . . . It is inadvisable to try and predict effects based on blood THC concentration alone.”20 Also in 2016, the AAA Traffic Safety Research Foundation conducted a study and concluded that “quantitative threshold for per se laws for THC following cannabis use cannot be scientifically supported.”


There are pending federal studies related to marijuana and driving. The National Institute on Drug Abuse is using a $1.4 million grant to conduct a five-year study to determine how marijuana impacts critical brain functions for driving. The National Highway Traffic Safety Administration is conducting a second research project to take initial steps towards developing a battery of tests to identify drivers who have recently used marijuana. The State of Colorado granted the University of Colorado $1.68 million to look at the impacts of marijuana use on driving.


In the midst of all of this attention on marijuana and driving, the long-awaited Gerhardt decision was handed down in September 2017. The applicability of standard field sobriety tests to marijuana-driving impairment presented a few important legal issues for the Massachusetts Supreme Court. One issue was that standard field sobriety tests were established to detect alcohol driving impairment—not marijuana or drugdriving impairment. Additionally, as the court noted, there are conflicting studies on the topic and no consensus in the scientific

community to support their applicability to marijuanadriving impairment.


Regardless, the Gerhardt court stated that “[t]he absence of scientific consensus regarding the use of standard [field sobriety tests] in attempting to evaluate marijuana intoxication  does not mean that they have no probative value.” As such, the court concluded that, although a police officer may testify about their observations related to standard field sobriety tests:


                A police officer may not suggest, however, on direct examination that an individual’s performance on  a[] [standard field sobriety test] established that the individual was under the influence of marijuana. Likewise, an officer may not testify that a defendant “passed” or “failed” any [standard field sobriety test], as this language improperly implies that the [standard field sobriety test] is a definitive test of marijuana use or impairment.


The court went even further and concluded that:


               The fact that the [standard field sobriety tests] cannot be treated as scientific “tests” of impairment means that evidence of performance on [standard field sobriety  tests], alone, is not sufficient to support a finding that a defendant’s ability to drive safely was impaired due to the

consumption of marijuana, and the jury must be so instructed.



What other factors should be considered in determining driving impairment? Perhaps toxicology reports indicating THC blood nanogram concentration levels; the degree of bad driving; physical evidence, such as marijuana paraphernalia or cigarettes in plain view; inculpatory statements, such as “I just smoked some marijuana”; an odor of marijuana; observations by law enforcement of characteristics like bloodshot eyes; and others as identified by the Gerhardt Court. Toxicology reports offering THC blood concentration levels are themselves under scrutiny. As noted above in the National Highway Traffic Safety Administration’s report to Congress, setting per se levels is not meaningful, and last year’s AAA Traffic Safety Research Foundation study concluded that “quantitative threshold for per se laws for THC following cannabis use cannot be scientifically supported.” If the toxicological findings also become an issue, then Massachusetts may only be left with the drug recognition expert observations as identified and supported by the ruling: bad driving, physical evidence, odor, and inculpatory statements.


This may cause the “road” to conviction in marijuana-driving cases to narrow in Massachusetts and perhaps in other Daubert states. Massachusetts, federal courts, and over half of the state courts in the U.S. use the Daubert standard for the admissibility of scientific evidence.30 Does this mean that other courts will adopt the Massachusetts analysis on the admissibility of standard field sobriety tests in marijuana-driving cases even though the Massachusetts decision is not binding on them? Is the Massachusetts Supreme Court ruling in Gerhardt

setting the stage for how courts should treat standard field sobriety tests for marijuana-driving-impairment cases and maybe even all drugged-driving cases?


What about other drugs and driving impairment? A recent report authored by the Foundation for Advancing Alcohol Responsibility and the Governors Highway Safety Association found that 43% of drivers who died in a crash had used a legal or illegal drug compared to 37% who tested above the illegal per se limit for alcohol.31 While this information may be indicative of an increase in drugged-driving fatalities as surpassing alcohol-driver fatalities, the report states that “[d]ata on drug presence in crash-involved drivers are incomplete in most jurisdictions, inconsistent from state to state, and sometimes inconsistent across jurisdictions within states.” Although the Foundation for Advancing Alcohol Responsibility has the best nationwide data on this matter, there are some shortcomings in the data because it only tested 57% of drivers involved in crashes. It is also important to note that driving under the influence of drugs or drugs found at the time of an autopsy is not necessarily equivalent to impaired driving.


All things considered, driving under the influence of marijuana in particular, and driving under the influence of drugs in neral, is an escalating problem for the roadways and the courts. State trial and supreme courts will have to make important decisions about how to address the science   stablishing impairment, the role of the drug recognition expert, and the applicability of standard field sobriety tests in drugged-driving cases. Will the Massachusetts findings regarding marijuana

and driving under a Daubert analysis influence how courts will treat driving under the influence of other drugs as well? Slowly he answers will come.