A Drug Enforcement Administration (DEA) agent, while patrolling a highway in an area under surveillance for suspected drug trafficking, noticed an apparently overloaded pickup truck with an attached camper traveling in tandem with a Pontiac. Savage (D1) was driving the truck, and Sharpe (D) was driving the Pontiac. The truck was riding low in the rear, and the camper did not bounce or sway appreciably when the truck drove over bumps or around curves. The agent concluded it was heavily loaded. Quilted material covered the rear and side windows of the camper. The agent decided to make an 'investigative stop' and radioed the State Highway Patrol for assistance. A Highway patrol car caught up with the Pontiac, and the pickup turned off the highway and onto a campground road. The officers followed the two vehicles as they exceeded the speed limit of 35 miles an hour. The road eventually looped back to the highway, onto which Ds turned and continued to drive south. The Highway patrol signaled both vehicles to stop. The pickup continued down the highway. The Highway patrol pursued the truck while the DEA pulled up behind the Pontiac. D produced a Georgia driver's license bearing the name of Raymond J. Pavlovich. DEA asked for local officers to hold D while he left to join the Highway Patrol. The Highway Patrol had stopped the pickup truck about one-half mile down the road. D1 had been ordered to get out and assume a 'spread-eagled' position against the side of the truck and patted him down. D1 produced his own Florida driver's license and a bill of sale for the truck bearing the name of Pavlovich. D1 said he was taking the truck to have its shock absorbers repaired. D1 became nervous when the officer told him he would be held until the DEA arrived. DEA arrived at the scene approximately 15 minutes after the truck had been stopped. DEA twice sought permission to search the camper, but D1 declined to give it, explaining that he was not the owner of the truck. DEA confirmed his suspicion that it was probably overloaded. He put his nose to the window and could smell marihuana. DEA removed the keys from the ignition, opened the rear of the camper, and observed a large number of burlap-wrapped bales resembling bales of marihuana. DEA then placed D1 under arrest and left him with the Highway Patrol. DEA returned to the Pontiac and arrested D. Approximately 30 to 40 minutes had elapsed between the time of the stop and arrest. The truck contained 43 bales weighing a total of 2,629 pounds. Acting without a search warrant, Cooke had eight randomly selected bales opened and sampled. Chemical tests showed that the samples were marihuana. Ds were charged with possession of a controlled substance with intent to distribute. Ds' motion to suppress the contraband, was denied and Ds were convicted. A divided panel of the Court of Appeals for the Fourth Circuit reversed the convictions. The court held the investigative stops unlawful because they 'failed to meet the requirement of brevity' thought to govern detentions on less than probable cause. 'The length of the detentions effectively transformed them into de facto arrests without bases in probable cause, unreasonable seizures under the Fourth Amendment.' The case was remanded by the Supreme Court, and the Court of Appeals again reversed the convictions. The Supreme Court granted certiorari.