First, a traffic violation serves as an objectively reasonable basis to pull over a car and briefly detain the occupants. A lawful traffic stop, even if it is a pretext to stop the driver for a drug violation, is reasonable regardless of the police officer’s motivation. Prolonged detention is only justified by a change in circumstances after the initial traffic stop or probable cause. Probable cause to arrest gives an officer the right to arrest and perform a subsequent search incident to the arrest. The probable cause can be supplied by an informant’s information (tip), if it is a reliable tip and it is corroborated. corroborated. In a bit of circular logic, if the search reveals what the tipster suggested would be there, the tip is then corroborated, and the evidence has a better chance of being admitted in court.