The text notes that the courts have prohibited as unreasonable the kind of pretextual stops exemplified by random, unscheduled stops. The case of Whren and Brown v. United States involved a legal challenge to a stop in which police officers had observed a traffic violation. When the police officer approached the driver's window, he observed plastic bags of what appeared to be cocaine in Whren's hands. The police arrested the suspects and recovered several types of illegal drugs from the vehicle. The appellate court decided that the police officers had probable cause to believe that the defendants had violated the traffic code. That rendered the stop reasonable under the Fourth Amendment, the drug evidence thereby discovered admissible, and the appellate court's decision correct. Questions and answers regarding police responsibilities and legal limitations related to traffic stops