In the recent case of Commonwealth v. Gerhardt, the Supreme Judicial Court took a major-league swing at the use of field sobriety tests (FSTs) by law enforcement to prove that a suspect is under the influence of marijuana. Correctly pointing out the obvious, that FSTs were designed to test alcohol sobriety, the court found that modern science has not quite embraced the idea of using such methods to determine marijuana impairment. To the extent that an FST has any use at all, it is to provide a controlled opportunity for observation of a driver: An officer may testify as to the general demeanor, appearance and behavior of a suspect while performing such tried and true activities as the horizontal gaze nystagmus test, the nine-step walk and turn test, and the alphabet and counting tests.
The court was so antagonized by the use of the term “field sobriety test” that it ordered a re-branding of the FST to fit its ruling in Gerhardt. Henceforth, when using an FST to measure a suspect’s observable conduct, it must be referred to in court as a “roadside assessment.” Just in case there was any meat left on the bone of the FST, the court went on to issue a model jury instruction, which advises, “The roadside assessments are not scientific tests of impairment of marijuana use. A person may have difficulty performing such tasks for many reasons unrelated to the consumption of marijuana … [E]vidence of how a defendant performed in roadside assessments, standing alone, is never enough to convict a defendant of operating under the influence of marijuana.”
In light of Gerhardt, one must wonder whether the use of “roadside assessments” has any value at all to law enforcement. A review of cases that support the conviction of operating a motor vehicle while under the influence of marijuana demonstrates that proof of such impairment need not require the suspect to step out of the motor vehicle. For instance, in Commonwealth v. Rosado, the police officer observed that there was a strong odor of marijuana in the car, the defendant’s eyes were red, his speech was slow, his answers to questions odd, and he laughed at inappropriate times. When asked by the officer whether he had any marijuana in the motor vehicle, the defendant stated, “If there was, I would have smoked [it].” At least the defendant had a sense of humor, but it did him no good. The Appeals Court upheld his conviction for driving under the influence of marijuana.
Clearly, state legislators are concerned, and for good reason. The public has embraced the use of marijuana for recreational purposes, but there is no general consensus among scientists as to what effect such use might have on an individual’s ability to safely operate a motor vehicle. Recent legislation establishes a commission to study the issue. In the meantime, law enforcement and the courts are left a bit in the lurch when it comes to assessing, with any degree of certainty, the evidence that will meet the legal definition of “impairment.”