Now that recreational marijuana use is legal for most adults in Massachusetts, police officers are likely to watch for signs of drugged driving. If they have reasonable suspicion you may be operating a vehicle under the influence of marijuana, officers may stop your vehicle and ask you to submit to field sobriety testing.
Field sobriety tests come in a few different forms. Usually, though, officers ask suspected OUI drivers to perform physical and mental tasks. While field sobriety tests may be effective for drunk driving, they may not be reliable for drugged driving.
The National Institute of Justice supported a study to determine how THC levels in participants’ blood and urine affected their cognitive and psychomotor abilities. THC, of course, is the compound in marijuana that produces a user’s high.
The study found no link between THC levels and cognitive or psychomotor impairment. In fact, participants with low levels of THC in their bodily fluids generally showed greater impairment than those with higher levels of the compound.
Field sobriety tests
The NIJ’s study also concluded that standard field sobriety tests are not effective for measuring marijuana intoxication. That is, study participants with high levels of THC in their bodies performed similarly to those with lower levels of THC. While more research is necessary, field sobriety testing for marijuana intoxication certainly appears to be unreliable.
Beyond field sobriety testing, officers have few tools to determine if someone may be driving under the influence of marijuana. Consequently, if an officer uses your failed field sobriety test to support your arrest, you may have a valid defense against the OUI charges you are facing.