It happened Thursday afternoon on SR 1 southbound at Biddle Toll Plaza in Middletown.
State troopers stopped 24-year-old Vance Turner for allegedly speeding.
During the traffic stop, one of the troopers noticed the smell of marijuana.
Police searched the vehicle and found a shopping bag containing five pounds of marijuana separated in plastic storage bags.
Authorities say the drugs have a street value of $10,000.
Turner was taken into custody, facing a number of drug charges.