After being stopped, the driver, Chandler Moore, 21, of Arlington, Texas, and a passenger, Richard Laster of Greenville, Miss., told different stories about their destination, raising police curiosity.
One said they were enroute to Lake Providence in Northeast Louisiana.
The driver declined to give permission to search the vehicle and a K-9 officer was called in.
Troopers said the dog alerted on 16.3 pounds of marijuana.
Laster is charged with possession of marijuana with intent to distribute, conspiracy to deliver marijuana, possession of drugs with a juvenile and possession of marijuana. He was held without bond.
Moore was charged with improper lane usage, possession of marijuana with intent to distribute, conspiracy to deliver marijuana, illegal carrying of a weapon and possession of drugs with a juvenile.
Information about other passengers in the vehicle was not available.