Pettit was driving across Utah when he was stopped for repeatedly crossing the fog line. During the stop, he was acting abnormally nervous (the trooper specifically described that his lower body was fidgeting, his whole arm was shaking when he handed over a driver's license, and he told the trooper twice in 25 seconds that he was making him nervous). Pettit's travel plans were also the sort of thing that makes any cop think of drug trafficking (he was driving a car registered to an absent third party one-way across the country with very little luggage or personal effects). Also, his license was suspended in both of the states where he had a driver's license.
The initial stop was at 3:32. At 3:43, the trooper had completed a citation for the traffic offense, but he did not actually give Pettit the citation or return Pettit's ID card to him. Instead, he asked for consent to search the car, which Pettit granted. During the search, he found $2000 cash. A K9 who showed up during the search quickly alerted to the scent of drugs, and 2.5 kg of cocaine were finally found in the spare tire.
In court, Pettit moved to suppress the evidence, arguing that the trooper unlawfully extended the stop without reasonable suspicion. His motion was denied, he was convicted, this appeal followed.
Although the police are allowed to do certain things during an ordinary traffic stop (such as request license and registration, run computer checks, issue citations, ask questions whether or not they are related to the stop, and request consent to search), a traffic stop may not extend beyond the time reasonably required to effectuate its purpose. An officer may only extend the traffic stop beyond that time if either 1- the encounter becomes a consensual encounter or 2- the officer develops reasonable suspicion of other criminal activity during the stop.
The Tenth Circuit held that at 3:43, the traffic stop was over. By then, the trooper had already completed all of the normal tasks associated with a traffic investigation, and was prepared to issue a citation (although he did not immediately do so). However, since the trooper did not return Pettit's documents to him, this had not become a consensual contact. So the important question is whether or not the Trooper had reasonable suspicion.
Reasonable suspicion has been defined by the Supreme Court as a particularized and objective basis for suspecting criminal conduct under a totality of the circumstances. It's not a difficult standard to meet, it doesn't require that an officer eliminate all innocent explanations first, or even that a suspect be more likely guilty than innocent. In this case, the factors listed above (Pettit's unusual nervousness, the normal indicia of drug trafficking, and even the suspended licenses) were enough to amount to reasonable suspicion when viewed as a whole. The detention thus being justified, Pettit's conviction was affirmed.