Field Sobriety Tests Invalid in Determining Whether Driver Is Intoxicated by Marijuana

With the legalization of marijuana in Massachusetts and Maine and the decriminalization of possession of small amounts of marijuana in Vermont and New Hampshire a new legal front has been established in determining how to measure an individual’s level of impairment when operating a motor vehicle.  The lack of specific scientific evidence as to how to detect impairment is one of the major reasons Vermont governor Phil Scott vetoed a bill to legalize possession of marijuana last year and continues to be a huge concern for Vermont law enforcement in their ability to arrest individuals for driving under the influence of marijuana or other drugs.

The Massachusetts Supreme Court decision in COMMONWEALTH V. GERHARD has now limited police officer’s ability to use the standardized field sobriety tests as evidence of drug impairment, tests which have long been validated to detect alcohol impairment.

“The research on the efficacy of FSTs to measure marijuana impairment has produced highly disparate results. Some studies have shown no correlation between inadequate performance on FSTs and the consumption of marijuana; other studies have shown some correlation with certain FSTs, but not with others; and yet other studies have shown a correlation with all of the most frequently used FSTs.”

As has been litigated in Vermont Courts (and recently won by Attorney Evan Chadwick in a drugged driving case), a law enforcement officer who is not a certified Drug Recognition Expert should not be able to  testify as to their opinion of impairment when investigating an individual for DUI-Drugs .  The Gearhardt decision adds an extra layer of protection for these types of investigations by limiting what evidence can be presented on the roadside investigation.