The discovery was made on Interstate 85 near Flowery Branch Road, police said.
Authorities said the driver gave the officer conducting the stop a false driver's license. Police said the officer found probable cause to search the vehicle and that a K-9 alerted them to an odor in the vehicle.
Police said they found two large black trash bags in the trunk with five bricks of marijuana and one large zip-close bag also containing marijuana.
Tyrone Alexander, 33, of Greenville, S.C., was arrested and taken to the Gwinnett Detention Center.
Alexander is charged with trafficking marijuana, false documents and driving on a suspended license. He is being held without bond.