§ 4.01. Officer-Initiated Encounters with Individuals

An encounter is a face-to-face interaction between an officer and a member of the public, conducted for the purpose of investigating unlawful conduct or performing a caretaking function. It does not include social, non-investigative, or non-caretaking interactions between a police official and a member of the public.

Consistent with current law, this Chapter adopts the following terms and definitions:

  • (a) “Initial encounter”: An encounter in which the officer does nothing to impede the individual from leaving or otherwise terminating the encounter—and a reasonable person would in fact feel free to do so
  • (b) “Stop”: An encounter that is brief in duration and does not constitute an arrest and that a reasonable person would not feel free to leave or otherwise terminate.
  • (c) “Frisk”: A pat-down search of an individual’s body during a stop, conducted over the individual’s clothing for the purpose of finding a weapon.
  • (d) “Custodial arrest”: An encounter in which an individual is taken into custody and transferred to a stationhouse or other temporary holding facility.


a. Encounters, generally. Face-to-face encounters between officers and members of the public are an essential—and common—aspect of police work. Officers approach people on the street to ask for information, or because they see someone behaving suspiciously and wish to investigate further. Officers conduct traffic stops and issue citations to enforce traffic laws. They break up fights and help defuse tense situations. And when necessary, they take individuals into custody. All of these are essential tools of law enforcement that, when used appropriately, enable officers to help maintain public safety.

At the same time, as discussed in greater detail throughout this Chapter, these sorts of interactions have the potential to erode the very sense of public safety and security that they are meant to promote. When officers treat residents in a harsh or aggressive manner, routinely stop individuals who are innocent of any criminal offense, or fail to explain their actions when there is ample opportunity to do so, community members may come to mistrust the police and question the legitimacy of law enforcement. Individuals who do not trust the police may be less likely to report crime or otherwise cooperate and engage with law enforcement in the co-production of safety. They also may be less willing to comply with the law. In addition, encounters that are unduly coercive, or are conducted in a discriminatory manner, can impose physical, dignitary, and other harms on the individuals involved.

These Principles offer guidance to agencies and to officers on how to use these tools in a way that promotes, rather than detracts from, law enforcement’s public-safety mission. Although policymaking around the use of encounters often is said to involve a tradeoff between liberty and privacy on the one hand and security on the other, that is not always the case. There are instances in which certain police tactics actually can undermine safety while intruding on liberty and privacy. When police act in a manner that is unduly coercive or intrusive, they may in fact be undermining the broader goal of keeping the public safe. And even when there is a tradeoff—which does occur at times—that line must be drawn carefully to maximize the benefits of policing while minimizing any harms. The Principles in this Chapter are designed to ensure that encounters between officers and members of the public are conducted in a manner that promotes the public’s sense of safety and security, while at the same time promoting the safety of the officers carrying out those actions.

b. Social interactions excluded. The focus of this Chapter is on interactions between officers and members of the public conducted for an investigative or community-caretaking purpose. The community-caretaking purpose refers to actions that are not initiated for the purpose of investigating crime, such as when an officer enters a home to render aid to someone inside. Beyond investigative and community-caretaking actions, officers also interact with members of the public in order to better get to know the community and learn about its problems and concerns. These sorts of interactions are not the subject of this Chapter, and are addressed separately in the Section on community policing, § 1.08.

c. Initial encounters. These Principles use the term “initial encounter” to describe any interaction between an officer and a member of the public that is investigative in character, but legally falls short of a stop or an arrest. Although courts sometimes describe these as “voluntary” or “consensual” encounters, these Principles intentionally do not adopt that language because of a concern that at least some of the encounters characterized this way by courts are not in fact voluntary or consensual.

d. Stops. Consistent with constitutional law, these Principles define a “stop” as an encounter in which a reasonable person would not feel free to leave or to otherwise terminate the interaction. At the same time, agencies should be aware that many individuals may not in fact feel free to leave in circumstances that courts have said fall short of a stop. Studies consistently have shown that individuals often do not feel free to walk away or decline to speak with officers—even if officers behave in a nonthreatening manner, or make clear that the individual may terminate the encounter at any point. Indeed, the notion that individuals should feel free to terminate an encounter initiated by law enforcement is somewhat in tension with the notion, also reflected in case law, that individuals should assist law enforcement and comply with law-enforcement requests. When officers ask a motorist, “may I see your license?” that is clearly a command even when phrased as a question. It is unclear whether all individuals would understand the question “may I speak with you?” differently. In addition, the degree to which an individual feels free to leave may depend on that person’s race, age, or gender, as well as prior experiences with law enforcement, which typically are factors that courts do not take into account, and of which officers themselves may be unaware. In cases of ambiguity, officers should ensure that they have a legitimate law-enforcement justification for initiating the encounter.

e. Frisks. This Principle borrows the terminology adopted by the Supreme Court in Terry v. Ohio, 88 S. Ct. 1868 (1968), to describe a limited pat-down search, conducted during a stop, over an individual’s clothing, for the purpose of finding a weapon. As the Terry Court itself acknowledged, however, the use of the term “frisk” should not be understood to minimize the seriousness of the physical intrusion that it entails, and the importance of ensuring, consistent with §§ 4.02 and 4.06, that it is used both lawfully and sparingly. Finally, as discussed in § 4.04, the Court has extended the Terry rule to permit officers, in the course of a vehicle stop, also to conduct a protective sweep of those areas within the passenger compartment of a vehicle that are within the driver or passengers’ immediate control. Although some courts have described these searches as “car frisks,” in order to avoid confusion these Principles use “frisk” to refer to the limited search of a person, and “protective sweep” to describe a search of an automobile or other area.

f. Custodial arrests. These Principles distinguish between a custodial arrest—in which an individual is taken into custody and transported to the stationhouse or to a temporary detention facility—and a brief detention out in the field conducted for the purpose of issuing a citation. Although both a citation and a custodial arrest must be supported by probable cause, a custodial arrest involves a much greater intrusion into the interests of the arrested person’s privacy, autonomy, and bodily integrity, and also potentially exposes the arresting officer to a greater risk of harm. For those reasons, these Principles urge legislatures and agencies to permit officers to issue a summons or a citation in lieu of custodial arrest, and encourage officers to in fact do so when permissible under state law and consistent with the goal of public safety. See § 4.05. These Principles also distinguish between custodial arrests and stops for the purpose of issuing a summons in describing the circumstances under which officers should be permitted to conduct a frisk or a search. See § 4.06.

Reporters’ Notes

1. Encounters, generally. Leaders both in and out of law enforcement have emphasized the need to ensure that encounters are conducted in a manner that promotes public safety and police legitimacy. In particular, officials have recognized that the goals of safety and legitimacy are not in conflict with one another, but in fact are interrelated: Tactics that emphasize crime reduction at the expense of trust and security do not make communities safer as a result. See, e.g., Police Executive Research Forum, Constitutional Policing as a Cornerstone of Community Policing 16 (2015) (“[o]ur past approaches to policing didn’t decrease the gap between us and the community. Increasing arrests for mostly nonviolent offenses didn’t necessarily make our communities safer” (quoting Chief Ron Teachman)). The International Association of Chiefs of Police (IACP), for example, has acknowledged that use of heavy-handed enforcement tactics by departments has resulted in “a reduction in perceptions of police fairness, legitimacy, and effectiveness,” to the detriment of public safety. IACP National Policy Summit on Community–Police Relations: Advancing a Culture of Cohesion and Community Trust (2015). Numerous studies support this conclusion. See Chris L. Gibson, Samuel Walker, Wesley G. Jennings & J. Mitchell Miller, The Impact of Traffic Stops on Calling the Police for Help, 20 Crim. Just. Pol’y Rev. 10, 1-21 (2009); Tom R. Tyler, Jeffrey Fagan & Amanda Geller, Street Stops and Police Legitimacy: Teachable Moments in Young Urban Men’s Legal Socialization (Columbia Law School Public Law & Legal Theory Working Paper Group Paper No. 14-380, April 2014); Jennifer Fratello, Andrés F. Rengifo & Jennifer Trone, Vera Institute of Justice, Coming of Age with Stop and Frisk: Experiences, Self-Perceptions, and Public Safety Implications (2013).

2. Initial encounters and stops. Studies have shown that individuals may not in fact feel free to terminate encounters that courts would describe as “consensual” or “voluntary” as a matter of law. Janice Nadler writes that “empirical studies over the last several decades on the social psychology of compliance, conformity, social influence, and politeness have all converged on a single conclusion: the extent to which people feel free to refuse is extremely limited under situationally induced pressures” that are common to police–citizen encounters. Janice Nadler, No Need to Shout: Bus Sweeps and the Psychology of Coercion, 2002 Sup. Ct. Rev. 153, 155 (2002); David K. Kessler, Free to Leave? An Empirical Look at the Fourth Amendment’s Seizure Standard, 99 J. Crim. Law & Criminology 51 (Fall 2008); Alisa M. Smith, et al., Testing Judicial Assumptions of the “Consensual” Encounter, 14 Fla. Coastal L. Rev. 285 (2013); Kathryne M. Young & Christin L. Munsch, Fact and Fiction in Constitutional Criminal Procedure, 66 S.C. L. Rev. 445 (2014). In one survey, less than one-quarter of respondents said that they would feel free to walk away if an officer approached them on the sidewalk and asked to speak with them, even if respondents did not wish to talk with the officer. Kessler, supra, at 53. Respondents who said they knew they had a legal right to walk away were only slightly more likely to feel free to do so. Id. at 78. As William Stuntz notes, “the truth is that ordinary people never feel free to terminate a conversation with a police officer.” William J. Stuntz, Terry’s Impossibility, 72 St. John’s L. Rev. 1213, 1215 (1998). See also Tracey Maclin, Black and Blue Encounters—Some Preliminary Thoughts about Fourth Amendment Seizures: Should Race Matter?,26 Val. U. L. Rev. 243, 250 (1991) (“common sense teaches us that most of us do not have the chutzpah or stupidity to tell a police officer to ‘get lost.’”).

A number of courts likewise have recognized that individuals may feel compelled to comply with officer requests, even when they are delivered in a polite and nonthreatening manner. The New Jersey Supreme Court, for example, has emphasized that “many persons, perhaps most, would view the request of a police officer to make a search as having the force of law.” State v. Johnson, 346 A.2d 66, 68 (N.J. 1975). The U.S. Supreme Court itself appears to acknowledge the gap between legal and actual voluntariness—in Schneckloth v. Bustamonte, the Court repeatedly used scare quotes around the terms “voluntary” and “consent.” 412 U.S. 218, 227, 228 (1973). The Court emphasized that the legal standard for voluntariness must strike a balance between legitimate law-enforcement interests and the need to ensure “the absence of coercion”—and that the Court’s test reflects “a fair accommodation” of the interests involved. Id. at 227.

3. Custodial arrests. Both state and federal courts have recognized a distinction between a “custodial” arrest and a brief detention out in the field conducted for the purpose of issuing a summons, which some have referred to as a “non-custodial arrest.” See, e.g., People v. Bland, 884 P.2d 312, 316 (Colo. 1994) (distinguishing “between custodial arrests, which are made for the purpose of taking a person to the stationhouse . . . and non-custodial arrests, which involve only temporary detention for the purpose of issuing a summons.”); Linnet v. State, 647 S.W.2d 672, 674-675 (Tex. Crim. App. 1983) (same); State v. McKenna, 958 P.2d 1017, 1021-1022 (1998) (same). The U.S. Supreme Court has likewise made clear that there is a constitutionally significant difference between a seizure for the purposes of issuing a summons or a citation, and a full custodial arrest. Knowles v. Iowa, 525 U.S. 113 (1998) (holding that a warrantless search incident to arrest is permissible only in the context of a custodial arrest). See also David A. Moran, Traffic Stops, Littering Tickets, and Police Warnings: The Case for A Fourth Amendment Non-Custodial Arrest Doctrine, 37 Am. Crim. L. Rev. 1143 (2000). There is no standard definition of a “custodial arrest” under the law. Courts and legislatures define it in different ways for different purposes. See Rachel A. Harmon, Why Arrest?, 115 Mich. L. Rev. 307, 310 (2016). The definition here emphasizes police custody and conveyance to a law-enforcement facility, and does not depend on whether a suspect is searched thoroughly or “booked” such that a permanent record is made of the encounter.

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