MARIJUANA LAW UPDATES BY: JUDGE MARY A. CELESTE (RET.)


Marijuana Driving Impairment: Is the Science There Yet?


M


assachusets will soon become the first state supreme court to rule on several debated issues on


marijuana driving impairment. On January 6, 2017 the court heard oral arguments in the case of Commonwealth v. Gerhardt,1


the court remanded the case with a series of questions for the trial court that found that there was no “firm science yet on how marijuana affects driving and at what dose.”2 Amongst other questions, the high


court asked: • 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 performance on field sobriety tests and impaired driving?


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


• Has any jurisdiction, foreign or domestic, recognized such a level?3 Depending on the answers to these


questions, we may soon have a court finding on: whether there’s an exact Delta 9 THC blood concentration level that equates to marijuana driving impairment; whether the alcohol standard field sobriety tests are applicable to determine marijuana driving impairment; and what observations are consistent with marijuana driving impairment. As far as marijuana driving cases


go, the facts in the Massachusetts case are not all that unusual. The defendant (Gerhardt) had tail lights out and, when stopped, the officer smelled marijuana. The defendant stated that he had smoked for 20 minutes and again three hours prior. The officer saw marijuana cigars on the floor of the car,


46 datia focus in which


in plain view. This established probable cause to request standard field sobriety testing. The defendant consented to the testing—the smell of marijuana alone, without the viewing of the “cigars,” was enough for a search. Later, the officer conducted a search of the car and found two “roaches.”


The Plain View Doctrine has been


expanded to include plain feel, plain smell, and plain hearing.4


The U.S.


Supreme Court stated that the smell of marijuana may provide probable cause to search.5


A majority of courts hold


that detection of the odor of either fresh marijuana or marijuana smoke, standing alone, provides probable cause for a warrantless search.6 Te defendant in the Massachusets


case “failed two of the standard field sobriety tests. He could not stand on one leg for 30 seconds. When asked to walk a line test, Gerhardt needed a couple of explanations and then didn’t stop and turn around aſter the suggested nine steps. He was able to count backwards and recite a portion of the alphabet.”7


The standard field sobriety tests


consist of: the horizontal gaze nystagmus (HGN),8


the one-leg stand, and the


walk-and-turn. Sometimes the Romberg or modified Romberg test is added, in which: “the 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.”9


With the exception of the HGN test, some say that the SFSTs apply in toto10 say that they are mildly sensitive11


One study , some , and still


others say that they apply to the walk-and- turn or one-leg stand only.12


stated that the finger to nose test was the best predicted cannabis impairment.13


Many


agree, however, that HGN does not apply.14 Observations of marijuana driving


impairment are almost too numerous to list. Te “green tongue” is popular. However, at the appellate court level, it is causing some concern in both Utah and Washington.15


Tere is also the modified


Romberg (MRB) eyelid tremors, increased pulse, elevated systolic blood pressure, dilated pupil size, lane weaving, driving on the wrong side, driſting, following too close, large distance from vehicle ahead, not responding to questions, reddened eyes, slow pupil reaction, nervousness, laughing, and facial expression, to name a few.16


It will be interesting to see if the


Massachusets court sanctions any of these, or makes other findings regarding observations consistent with marijuana driving impairment. Although there was no discussion of blood


testing of the defendant in the Massachusets case, the high court did ask the lower court if there was a level that is generally accepted to establish impairment in driving. With respect to THC blood


concentration levels and marijuana driving impairment, again the reports and studies are mixed. Te National Highway and Transportation Safety Administration (NHTSA) has 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 patern of use as well as dose . . . It is inadvisable


summer 2017


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