Young driver stopped for defective headlight and license plate lights. Officer notes distinct odor of burnt marijuana and driver admits to smoking earlier in the evening in Maine where MJ is legal. Officer requests driver participate in standard field sobriety tests. Driver does remarkably well on standard HGN, walk and turn and one legged stand tests, but DUI arrest follows. Defense prepared to argue police officer lacked expertise, education or training to reach an admissible opinion of impairment by marijuana or probable cause to arrest. Further, defense contends standard field sobriety tests are not designed for detection of impairment by marijuana. Prosecution agrees to not file DUI Drugs complaint before scheduled arraignment.