Police officers stop over 50,000 drivers per day, Stanford University’s Open Policing Project found. In Whren v. United States, the U.S. Supreme Court unanimously ruled in 1996 that if a driver committed a traffic violation but the officer stopped them due to other suspicions unrelated to the traffic violation, the search is still reasonable and legal under the Fourth Amendment. The officer accused Parker of driving 57 mph in a 35 mph zone and failing to stop at the police officer’s siren.