In Rodriguez v. United States, the Supreme Court held that the Fourth Amendment prohibits police officers from extending a traffic stop to investigate matters unrelated to the original purpose of the stop. While officers may investigate such matters simultaneous with routine traffic-stop activities like obtaining identification and registration, they may not "add time" to a stop to conduct any unrelated investigation (absent reasonable suspicion to do so).
In United States v. Brinson, No. CR-119-096 (S.D. Ga.), a Georgia district court recently applied Rodriguez and held that an officer's intentional 100-second delay in issuing a traffic ticket to ask about transporting drugs violated the Fourth Amendment. The stop was for a defective brake light. When checking for outstanding warrants, the officer discovered that the defendant had a prior drug conviction. So he suspended the process of writing a ticket to ask about possible drug activity. After a few questions, the defendant fairly quickly admitted that he had "weed" in the car. The court suppressed the evidence and statements, because the officer impermissibly added time to the stop to ask about drugs. "Even though only one minute and forty seconds elapsed from the moment Deputy Snyder exited his patrol car until Defendant admitted possession of marijuana, this unconstitutionally prolonged the traffic stop and exceeded its narrow purpose."
This opinion joins a few others, holding that even short detours into unrelated matters during a traffic stop are prohibited. See United States v. Clark and United States v. Campbell, where brief questioning about unrelated matters impermissibly extended each stop. (Good faith reliance on prior case law saved the stop in Campbell, but should have less force going forward now that Rodriguez is four years old).