State police said they found a kilogram of cocaine during a traffic stop on Interstate 93 in Andover Wednesday afternoon.
Johnny V. Nunez, 31, of Roxbury, was charged with trafficking heroin.
Police said Trooper James McTeague stopped Nunez's Acura MDX because it had no inspection sticker and he wasn't staying in his lane, police said.
McTeague said he found drug paraphernalia inside the vehicle.
Trooper Brian Cooper and K9 Drako searched the car and found the heroin, police said.