BOSTON (AP) — Massachusetts officials promised a crackdown Wednesday on marijuana-impaired driving as the state prepared for full implementation of the voter-approved law legalizing adult use of recreational pot.
State police said they were increasing the number of officers with special training in detecting whether motorists are under the influence of THC, the psychoactive chemical in marijuana.
One continuing hurdle for law enforcement is the lack of a reliable scientific test, similar to a breath test for alcohol, to measure THC impairment.
Officials also unveiled a public education media campaign aimed at younger adults that uses a humorous touch to drive home the risks associated with driving while high. One TV spot depicts an obviously stoned young man repeatedly and futilely attempting to light a gas grill without a propane tank, suggesting how dangerous it might be if the man tried to drive somewhere to fill the tank.
Arthur Kinsman, regional administrator for the National Highway Traffic Safety Administration, said the goal isn’t to ‘‘demonize’’ marijuana use, but change perceptions that it’s safer to drive after using pot than after drinking alcohol.
‘‘This isn’t a Cheech and Chong movie, where everybody is kind of laughing and driving along and everyone is laid back,’’ said Kinsman, referring to the popular 1970s-era stoner comedy duo.
Massachusetts voters were among those in four states that approved recreational marijuana questions last November, joining four states that had done so previously.
Jennifer Queally, undersecretary of public safety for law enforcement, cited evidence that those earlier states had experienced a spike in marijuana-related highway crashes since legalization.
A recent study by the Highway Loss Data Institute, a leading insurance research group, found that collision claims in Colorado, Washington and Oregon went up 2.7 percent in the years since legal recreational marijuana sales began, when compared with surrounding states.
Drivers who are high on marijuana demonstrate slower reaction times, sleepiness and more difficulty estimating time and distance, according to the National Highway Traffic Safety Administration.
Col. Richard McKeon, head of the Massachusetts State Police, said law enforcement planned to increasingly rely on drug recognition experts, officers who are trained in identifying drug impairment. There are currently 33 such experts in the state police force and 141 total in departments around the state, he said, with funding available to add another 60 in 2018.
But McKeon acknowledged the current lack of a conclusive test for measuring THC impairment makes prosecutions difficult.
‘‘We can testify to our observations and we bolster that with our training and our experience and that is how we bring these cases forward,’’ he said. ‘‘But it is a challenge.’’
A recently passed bill that makes revisions to the Massachusetts law included creation of a task force to study ‘‘all aspects of law enforcement personnel ability to properly test impaired operators and prevent impaired operation of motor vehicles.’’
While questioning some of the methodology behind studies that link marijuana legalization to increases in highway crashes, cannabis industry representatives have generally embraced efforts by states to tackle impaired driving.
Mike Dundas, chief executive of Sage Naturals, a medical marijuana dispensary in Cambridge, said his staff is trained to discuss the risks with customers.
‘‘We urge other dispensaries to join us in partnering with the state to raise awareness about the dangers of smoking and driving,’’ said Dundas.