Terry v. Ohio, 392 U.S. 1 (1968), was a landmark U.S. Supreme Court decision in which the Court ruled that it is constitutional for American police to "stop and frisk" a person they reasonably suspect to be armed and involved in a crime. Specifically, the decision held that a police officer does not violate the Fourth Amendment to the U.S. Constitution's prohibition on unreasonable searches and seizures when questioning someone even though the officer lacks probable cause to arrest the person, so long as the police officer has a reasonable suspicion that the person has committed, is committing, or is about to commit a crime. The Court also ruled that the police officer may perform a quick surface search of the person's outer clothing for weapons if they have reasonable suspicion that the person stopped is "armed and presently dangerous." This reasonable suspicion must be based on "specific and articulable facts," and not merely upon an officer's hunch.
A Terry stop in the United States allows the police to briefly detain a person based on reasonable suspicion of involvement in criminal activity. Reasonable suspicion is a lower standard than probable cause which is needed for arrest. When police stop and search a pedestrian, this is commonly known as a stop and frisk. When police stop an automobile, this is known as a traffic stop. If the police stop a motor vehicle on minor infringements in order to investigate other suspected criminal activity, this is known as a pretextual stop. Additional rules apply to stops that occur on a bus.
A traffic stop, commonly referred to as being pulled over, is a temporary detention of a driver of a vehicle by police to investigate a possible crime or minor violation of law.
Reasonable suspicion is a legal standard of proof in United States law that is less than probable cause, the legal standard for arrests and warrants, but more than an "inchoate and unparticularized suspicion or 'hunch'"; it must be based on "specific and articulable facts", "taken together with rational inferences from those facts", and the suspicion must be associated with the specific individual. If police additionally have reasonable suspicion that a person so detained is armed and dangerous, they may "frisk" the person for weapons, but not for contraband like drugs. However, if the police develop probable cause during a weapons frisk, they may then conduct a full search. Reasonable suspicion is evaluated using the "reasonable person" or "reasonable officer" standard, in which said person in the same circumstances could reasonably suspect a person has been, is, or is about to be engaged in criminal activity; it depends upon the totality of circumstances, and can result from a combination of particular facts, even if each is individually innocuous.
City of Indianapolis v. Edmond, 531 U.S. 32 (2000), was a United States Supreme Court case in which the Court held, 6–3, that police may not conduct vehicle searches, specifically ones involving drug-sniffing police dogs, at a checkpoint or roadblock without reasonable suspicion. In the case, the Indianapolis Police Department was conducting warrantless searches of vehicles, without individualized suspicion, for the purpose of "general crime control". Previous Supreme Court decisions had given the police power to create roadblocks for the purposes of border security and removing drunk drivers from the road, but in this decision, the Court limited police power, holding that the search can only occur if it was designed to serve special needs, beyond the normal need for law enforcement.
Illinois v. Caballes, 543 U.S. 405 (2005), was a decision by the Supreme Court of the United States in which the Court held, 6–2, that the use of a drug-sniffing police dog during a routine traffic stop did not violate the Fourth Amendment, even if the initial infraction is unrelated to drug offenses. In the case, Illinois native Roy Caballes was charged with narcotics trafficking after Illinois State Police uncovered marijuana in the trunk of his car during a routine traffic stop for speeding. Justice John Paul Stevens wrote for the six-justice majority that a well trained police dog will only alert to the presence of illegal substances that no citizen has the right to possess, and therefore it is not unconstitutional for the police to use a dog to uncover it. Chief Justice William Rehnquist took no part in the consideration of this case, and did not author an opinion.
United States v. Arvizu, 534 U.S. 266 (2002), is a case in which the Supreme Court of the United States unanimously reaffirmed the proposition that the Fourth Amendment required courts to analyze the reasonableness of a traffic stop based on the totality of the circumstances instead of examining the plausibility of each reason an officer gives for stopping a motorist individually.
Consent searches are searches made by police officers in the United States based on the voluntary consent of the individual whose person or property is being searched. The simplest and most common type of warrantless searches in the United States are searches based upon consent. No warrant, probable cause or reasonable suspicion is required to perform a search if a person, or someone else with the proper authority, consents to a search.
A random checkpoint is a military and police tactic. In a military context, checkpoints involve the setup of a hasty roadblock by mobile truck- or armored vehicle-mounted infantry to disrupt unauthorized or unwanted movement or military activity and to check for valid identification and search for contraband, fugitives, or weapons that are not permitted in civilian hands. Random checkpoints are set up to achieve surprise, as opposed to known permanently located checkpoints, which suspects could circumvent. They are often established in locations where they cannot be observed by approaching traffic until it is too late to withdraw and escape without being observed.
Brendlin v. California, 551 U.S. 249 (2007), was a decision by the Supreme Court of the United States that held that all occupants of a car are "seized" for purposes of the Fourth Amendment during a traffic stop, not just the driver.
Illinois v. Lidster, 540 U.S. 419 (2004), was a case in which the Supreme Court of the United States ruled that the Fourth Amendment permits the police to use a roadblock to investigate a traffic incident.
United States v. Brignoni-Ponce, 422 U.S. 873 (1975), was the case in which the Supreme Court determined it was a violation of the Fourth Amendment for a roving patrol car to stop a vehicle solely on the basis of the driver appearing to be of Mexican descent. A roving patrol car must have articulable facts that allow for an officer to have a reasonable suspicion that the person is carrying illegal aliens beyond their ethnicity. The Court handed down a 9–0 decision that affirmed the Circuit Court's ruling in the case.
Whren v. United States, 517 U.S. 806 (1996), was a unanimous United States Supreme Court decision that "declared that any traffic offense committed by a driver was a legitimate legal basis for a stop."
Pennsylvania v. Mimms, 434 U.S. 106 (1977), is a United States Supreme Court criminal law decision holding that a police officer ordering a person out of a car following a traffic stop and conducting a pat-down to check for weapons did not violate the Fourth Amendment to the United States Constitution.
Heien v. North Carolina, 574 U.S. 54 (2014), was a decision by the United States Supreme Court, ruling that a police officer's reasonable mistake of law can provide the individualized suspicion required by the Fourth Amendment to the United States Constitution to justify a traffic stop. The Court delivered its ruling on December 15, 2014.
Rodriguez v. United States, 575 U.S. 348 (2015), was a United States Supreme Court case which analyzed whether police officers may extend the length of a traffic stop to conduct a search with a trained detection dog. In a 6–3 opinion, the Court held that officers may not extend the length of a traffic stop to conduct a dog sniff unrelated to the original purpose of the stop. However, the Court remanded the case to the United States Court of Appeals for the Eighth Circuit to determine whether the officer's extension of the traffic stop was independently justified by reasonable suspicion. Some analysts have suggested that the Court's decision to limit police authority was influenced by ongoing protests in Ferguson, Missouri.
Navarette v. California, 572 U.S. 393 (2014), was a case in which the United States Supreme Court clarified when police officers may make arrests or conduct temporary detentions based on information provided by anonymous tips. In 2008, police in California received a 911 call that a pickup truck was driving recklessly along a rural highway. Officers spotted a truck matching the description provided in the 911 call and followed the truck for five minutes, but did not observe any suspicious behavior. Nevertheless, officers conducted a traffic stop and discovered 30 pounds (14 kg) of marijuana in the truck. At trial, the occupants of the car argued that the traffic stop violated the Fourth Amendment of the United States Constitution, because the tip was unreliable, and officers did not personally observe criminal activity. Writing for a majority of the Court, Justice Clarence Thomas held that the 911 call was reliable, and that officers need not personally observe criminal activity when acting upon information provided by an anonymous 911 call.
In the law, the totality of the circumstances test refers to a method of analysis where decisions are based on all available information rather than bright-line rules. Under the totality of the circumstances test, courts focus "on all the circumstances of a particular case, rather than any one factor". In the United States, totality tests are used as a method of analysis in several different areas of the law. For example, in United States criminal law, a determination about reasonable suspicion or probable cause is based on a consideration of the totality of the circumstances.
United States v. Sharpe, 470 U.S. 675 (1985), was an important decision of the U.S. Supreme Court in which the Court explained how long police are permitted to stop vehicles as part of an investigatory stop before violating the Fourth Amendment. A seven-member majority of the Court determined the twenty minute stop in this case was legal, so the government won. However, the Court declined to adopt a bright line rule, deciding instead that "common sense and ordinary human experience must govern over rigid criteria." The Court announced that the rule for determining whether a detention is too long will depend on whether the police "diligently pursued" an investigation to quickly confirm or dispel their suspicions. The Court clarified that judges should avoid "unrealistic second-guessing" of police and should take into account "swiftly developing situation[s]." Sharpe has been frequently cited, and is the framework used to challenge unduly prolonged police stops in thousands of criminal cases.
United States v. Cortez, 449 U.S. 411 (1981), was a United States Supreme Court decision clarifying the reasonable suspicion standard for the investigative stop of a vehicle.
