Massachusetts SJC Limits Police Testimony on Sobriety Tests for DUI/Marijuana Cases

Whether and what kind of sobriety tests would be allowed in court to prosecute drivers suspected of operating while under the influence of marijuana, was a question just waiting to be answered from the moment pot was legalized in Massachusetts – whether for medical or recreational use.  Well, the legal community now has the first such indication of those legal boundaries.

In a decision released just two days ago, the Massachusetts Supreme Judicial Court (SJC) unanimously restricted the ability of police officers to testify as to their own, subjective opinions of whether or not a given suspect was driving under the influence of pot.  Before going further, some quick contrast is needed here to explain what evidence is allowed in Massachusetts OUI/DUI alcohol cases:  In traditional DUI arrests, officers typically require the driver to perform what are called Field Sobriety Tests (“FST’s”), which consist of various tests such as walking heel-to-toe, reciting the alphabet, standing on one leg, and an additional test known as a Horizontal gaze nystagmus test, which measures the responsiveness of the eyes to a moving object such as a pen.  All of these are scientifically accepted indicators of alcohol intoxication.  If a suspect fails those tests, an officer may testify in court that the defendant failed the tests.  However, in this important decision, the court ruled that, due to the fact that there is as of present date no scientific consensus that these Roadside Sobriety Tests can definitively prove that a person is intoxicated by marijuana, the court limited what an officer can testify to on the stand.

The SJC decision stems from a February 2013 arrest by state police of a driver who was stopped for allegedly driving with his head lights off; the name of the case is Commonwealth v. Gerhardt.  The trooper in that case testified that he observed smoke inside the vehicle and smelled marijuana.  He also testified that the driver acknowledged that he had previously smoked about a gram of pot, and was unable to perform a “walk-and-turn” test, and was not able to stand on one foot, according to the trooper.  The defendant’s attorney objected to the trooper’s conclusions about whether or not the defendant was “high” on cannabis, and the SJC took direct appellate review of the case before it went any further.

The high court’s (excuse the pun) justices also noted that the effects of cannabis on users are more complex than with alcohol and less correlated to an amount consumed.  They concluded that these factors make it difficult for an untrained observer to conclude whether or not someone is high. The most salient part of the decision said that “Because the effects of marijuana may vary greatly from one individual to another, and those effects are as yet not commonly known, neither a police officer nor a lay witness who has not been qualified as an expert may offer an opinion as to whether a driver was under the influence of marijuana.”

Pot users who think they can now toke away and drive, better think twice, for two reasons:

  • The ruling made clear that police can still arrest any driver that they believe is high, and they can still describe in court how the defendant driver acted during the roadside tests. As an example, an officer could tell a jury that a driver was unable to walk a straight line. The ruling merely prevents the officer from actually terming or describing the task as a “test”, nor can an officer testify that a defendant driver “failed” it. An officer could also testify that a defendant smelled strongly of marijuana and seemed confused; but the officer could not use those observations to arrive at a subjective conclusion that the driver was, in fact, high. Such conclusions by an officer would be allowed if the defendant were being prosecuted for OUI/alcohol.


  • Driving after smoking or ingesting marijuana is irresponsible and selfish (and that comes from a Massachusetts drug charges lawyer who, even though I don’t use cannabis recreationally, supported decriminalization and legalization of marijuana, for both medical and recreational use.) Let’s be honest:  We all know that if someone wants a buzz, whether from alcohol of cannabis, driving should be out of the question.

As a Massachusetts drug charges defense lawyer, I think the most important part of the opinion is the court’s emphasis that, despite the above limitations, “jurors are still permitted to utilize their common sense” in weighing whether or not the sobriety assessments and other evidence indicate impairment due to cannabis use.  The translation comes down roughly to this:  Just because police officers can’t testify that a DUI-marijuana defendant didn’t “fail” a “test”, that doesn’t mean a jury still won’t see through to what was going on, if the defendant exhibited  number of other symptoms of being high.

Bottom line:  Will this ruling mean that prosecutors will now have a very difficult time convincing a jury or judge that a defendant being prosecuted for OUI/marijuana was, in fact, operating under the influence?  Probably not a great deal:  Juries will use common sense, which this decision encourages.    My outlook, as a Massachusetts OUI/drugs lawyer, remains the same:  If you’re going to use either port, alcohol, or any other drug – legal or illegal – do not drive.

Also, I believe that we can expect that in the not too distant future, the esteemed Massachusetts Legislature will pass either a bill or new regulations, establishing blood concentrations for cannabis that establish impairment, just as we presently have blood alcohol concentration standards that are measurable by either breathalyzers (when they work properly,) or by blood tests.  We’ll soon see the same types of standards and tests for marijuana.  And that will probably be a good thing, when it comes to public safety – which we should all be concerned about.

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