Massachusetts officials promised a crackdown Thursday 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.