Stops and Seizures

In Whren v. United States, the Supreme Court unanimously held that a traffic stop supported by probable cause does not violate the Fourth Amendment just because officers may have had an additional investigative motive. The decision affirmed an objective Fourth Amendment rule for traffic stops.

Terry v. Ohio, 392 U.S. 1 (1968), upheld a limited stop and frisk based on reasonable suspicion and safety concerns. The decision recognized that stops and frisks are Fourth Amendment events, but allowed a narrow weapons pat-down without probable cause when specific facts make the intrusion reasonable.

In Heien v. North Carolina, the Supreme Court held that an officer's objectively reasonable mistake about the law can still create reasonable suspicion for a traffic stop under the Fourth Amendment. The stop began with one nonworking brake light, even though state law was later read to require only one working stop lamp.