Yesterday, the Massachusetts Supreme Judicial Court issued its decision in Commonwealth v. Gerhardt, a case challenging whether field sobriety tests can be admitted into evidence against a individual charged with operating under the influence of marijuana. Field sobriety tests were developed to assess a individual's impairment based on the consumption of alcohol. They were not designed to assess a individual's impairment based on the ingestion of drugs.

The Commonwealth and defense attorneys presented conflicting research to the Court -- the results from studies presented ranged from a strong correlation of ingestion of marijuana and performance on the field sobriety tests, to some correlation, to no correlation whatsoever. Further, the Court was presented with findings that individuals who have consumed marijuana are affected differently, and "[n]o studies have concluded that any specific characteristics are routinely found in people who have used marijuana and were impaired." 

The Court ultimately held that field sobriety tests can be used to evaluate a citizen who an officer believes to be under the influence of marijuana, and these tests can be admitted into evidence through an officer's testimony at trial. The Court found that performance on field sobriety tests is relevant, and "provide[s] a link in the chain of proof." An officer is permitted to testify about their observations "to the extent that [the tests] are relevant to establish a driver's balance, coordination, mental acuity, and other skills required to safely operate a motor vehicle."

However, in recognizing the conflicting research about whether field sobriety tests truly correlate to impairment based on the ingestion of marijuana, the Court placed significant limitations on a police officer's testimony about an individual's performance:

First, the Court held that field sobriety test cannot be treated as scientific tests to establish impairment based on the ingestion of marijuana. An officer must now refer to field sobriety tests as "roadside assessments" during their testimony so as not to suggest that these tests are a scientific validation of an individual's impairment based on ingestion of marijuana. 

Second, a police officer may not testify that an individual's performance of field sobriety tests, or roadside assessments, establish that the individual was under the influence of marijuana. Nor can officer testify that an individual "passed" or "failed" any field sobriety test since this type of language implies that performance on these tests is definitive of impairment. 

Third, a police officer may not testify that it is their opinion that an individual was under the influence of marijuana. Only a qualified expert is able to provide this type of opinion.

Fourth, evidence of an individual's performance on field sobriety tests alone is never enough for the Commonwealth to prove that an individual operated under the influence of marijuana.

Fifth, while there is no scientific consensus on what, if any, physical characteristics indicate marijuana intoxication, jurors are permitted to use their own common sense in evaluating whether the Commonwealth introduced sufficient evidence to satisfy its burden. 

Sixth, the Court drafted a jury instruction that is to be used in prosecutions for operating under the influence of marijuana.