§ 4.06. Consent Searches

(a) During any encounter, an officer may ask for permission to search a person or a person’s property.

(b) Agencies should adopt policies to ensure that consent searches are used sparingly and only in circumstances in which they are likely to be productive. Specifically, agencies should consider:

  • (1) prohibiting officers from seeking consent to search absent reasonable suspicion to believe that the search will turn up evidence of a crime or violation;
  • (2) requiring officers to explain (when not inconsistent with investigative objectives) why they want to conduct a search and that the individual has the right to refuse consent; and
  • (3) requiring officers to obtain and document, either in writing or in some other reliable form such as body-worn-camera video, acknowledgement that consent was sought and provided.

(c) The scope of a consent search must not exceed the scope of the consent given, and should be no broader than necessary to achieve the investigative objective motivating the request for consent.


a. Animating concerns. Consent searches serve a number of important functions. Society has an interest in detecting and deterring criminal activity. If an officer lacks probable cause to justify a search, but nevertheless has reason to believe that an individual is involved in criminal activity, a consent search may be the only means of uncovering evidence or furthering the investigation. Even if an officer has probable cause to believe that a crime has been committed, and could thus obtain a warrant, the target of the search may prefer to grant the officer permission to search so as to quickly dispel the officer’s suspicion.

At the same time, there is a risk that consent searches may be used in ways that impose unnecessary costs on the public, and, in doing so, undermine public trust in the police. These include possible privacy and dignitary costs, among others. Individuals who consent to a search may nevertheless find the experience intrusive and unsettling. Many of the circumstances in which officers seek consent—such as traffic or pedestrian stops—are inherently coercive. Even if an individual is advised of his or her right to refuse, the individual may feel compelled to give officers permission to search to avoid unduly prolonging the encounter or increasing the likelihood of getting a citation. It is therefore difficult to conclude with confidence that anyone who is asked by a police officer for permission to search “consents” in the ordinary meaning of that term. An individual who “consents” may nevertheless perceive the encounter as involuntary and illegitimate—particularly if the person is innocent of any crime. These concerns are exacerbated by the fact that consent searches have the potential to be used in racially disparate ways. In one jurisdiction after another, studies have shown that officers are more likely to seek consent from minority drivers and pedestrians—but that searches of minorities are in fact less likely to turn up evidence or contraband. These disparities can further undermine legitimacy and trust. Finally, a number of studies suggest that frequent use of consent searches may be a poor use of officer time. Hit rates often are extremely low, and even “successful” searches often turn up only small quantities of drugs.

In view of these concerns, a number of jurisdictions have limited the use of consent searches in various ways. Many departments and states require officers to obtain written acknowledgement of consent. Others require that officers have articulable suspicion that the search will turn up evidence or contraband before asking for permission to search. Still others require officers to obtain supervisor approval prior to conducting a search. Finally, at least one state highway patrol has banned the use of consent searches outright.

b. Use of the term “consent.” Although there are reasons to doubt whether any given search conducted with permission is in fact “consensual” in the ordinary sense of the term, these Principles nevertheless adopt the phrase “consent searches” to describe the police activity in question. The phrase is widely used throughout judicial opinions and police department manuals. Because one of the primary goals of these Principles is to provide guidance to agencies—as well as legislatures that may adopt statutes to regulate agency or officer conduct—these Principles, to the extent possible, use familiar terms to avoid the possibility of confusion and to increase the likelihood of adoption.

c. Requirement of reasonable suspicion and explanation. Officers should not seek consent to conduct a search unless they have reasonable suspicion to believe that the search will turn up evidence of a crime and unless they can explain to the individual why they would like to conduct a search, to the extent this is not inconsistent with investigative objectives. A reasonable-suspicion standard recognizes society’s interest in uncovering evidence of criminal activity, and it gives officers an important tool with which to close the investigative gap between their initial suspicions and probable cause for a search or arrest. At the same time, the standard eliminates the use of consent searches in precisely the circumstances in which they are least likely to be efficacious, and most likely to undermine legitimacy and trust. Absent reasonable suspicion, an officer at best has a mere hunch that something is off—and at worst, is operating on the basis of explicit or implicit bias, unfounded hunch, whim, or caprice. Studies suggest these are precisely the circumstances in which officers’ actions are most likely to disproportionately affect minority groups. The additional requirement of an explanation can both assuage fears that the officer is acting arbitrarily and help define the scope of the consent.

d. Written acknowledgement. A reasonable-suspicion requirement is more closely tailored to the underlying concerns with consent searches than is the requirement of written acknowledgement that the target was informed that he or she did not have to consent to the search. Research casts serious doubt on the idea that consent forms meaningfully alter the inherent coerciveness of police–citizen encounters. An individual who feels compelled to consent to a search—out of deference to authority or fear of the consequences of refusing—may feel just as compelled to consent in writing.

“Consent” forms still can serve an important purpose: they create a record of the encounter, and thus help ensure that officers inform individuals of their right to refuse permission to search. But these same purposes can be achieved in other ways—for example, by documenting an encounter using body-worn-camera video. Indeed, body-worn-camera video may be more effective at documenting the circumstances under which an individual agrees to permit officers to search. For this reason, these Principles do not require that consent be obtained in writing if the department has mechanisms in place to document the encounter in an equally effective way.

Reporters’ Notes

Consent searches are a common tool for police departments. Courts repeatedly have stressed the importance of permitting officers to seek cooperation from the public, as well as the fundamental value of consent itself. As the U.S. Supreme Court observed, “[i]n a society based on law, the concept of agreement and consent should be given a weight and dignity of its own.” United States v. Drayton, 536 U.S. 194, 207 (2002). See also Fernandez v. California, 134 S. Ct. 1126, 1132 (2014); Schneckloth v. Bustamonte, 412 U.S. 218, 243 (1973). From the perspective of police departments, seeking consent to search saves officers time by forgoing the procedural requirements of obtaining a warrant. See, e.g., Tracey Maclin, The Good and Bad News About Consent Searches in the Supreme Court, 39 McGeorge L. Rev. 27, 31 (2008). Additionally, asking for consent is sometimes the sole investigatory tool available to an officer who believes a crime has occurred. As the Court acknowledged in Schneckloth, “[i]n situations where the police have some evidence of illicit activity, but lack probable cause to arrest or search, a search authorized by valid consent may be the only means of obtaining important and reliable evidence.” Schneckloth, 412 U.S. at 227.

1. Animating concerns. Despite their legality and usefulness, various issues surrounding consent searches mitigate against their broad use. First and importantly, “consent” searches often are not voluntary in any meaningful sense. Statistics reported by police departments suggest that the vast majority of people consent to searches when asked to do so by police officers—which raises serious doubts about how voluntary these searches are. L.A. Police Dep’t, Arrest, Discipline, Use of Force, Field Data Capture and Audit Statistics and the City Status Report Covering Period of January 1, 2006-June 30, 2006, at 8 (2006) (reporting that of 16,228 requests for consensual search made during the first half of 2006, 16,225, or 99.9 percent, were granted); Alexander Weiss & Dennis P. Rosenbaum, Univ. of Illinois at Chicago, Illinois Traffic Stops Statistics Act 2010 Annual Report: Executive Summary 10 (2011) (reporting that in 2010, requests for consent to search during a traffic stop were granted 82 percent of the time). Extensive psychological research suggests that people asked to consent often do not feel free to refuse, either because they feel required to comply with the request of an authority figure or because they fear the consequences of refusal. As Marcy Strauss writes, there is “abundant evidence” that “individuals read a police officer’s request as a demand that they will . . . most assuredly obey.” See, e.g., Marcy Strauss, Reconstructing Consent, 92 J. Crim. L. & Criminology 211, 240-241 (2001); see also Janice Nadler, No Need to Shout: Bus Sweeps and the Psychology of Coercion, 2002 Sup. Ct. Rev. 153, 155; Illya D. Lichtenberg, Voluntary Consent or Obedience to Authority (Unpublished Dissertation, Rutgers University, 1999). As noted earlier in this Chapter, even the U.S. Supreme Court has recognized that consent may not be truly voluntary. Schneckloth v. Bustamonte, 412 U.S. at 227, 228; § 4.01, Reporters’ Notes.

Overreliance on consent searches can have negative effects on public perceptions of police legitimacy. In 2008, the Bureau of Justice Statistics reported that 18.4 percent of people asked to consent to a search reported the officer’s actions as both improper and disrespectful, as compared to 5.6 percent of drivers who were not subject to a consent search. In addition, 36.6 percent of those asked to consent to a search said that they perceived the underlying stop to be illegitimate as a result, compared to 5.6 percent of drivers generally. Jacinta M. Gau, Consent Searches as a Threat to Procedural Justice and Police Legitimacy: An Analysis of Consent Requests During Traffic Stops, 24 Crim. Just. Pol’y Rev. 752, 768 (2013).

There is also a significant risk that consent searches may be used in racially disparate ways. Department statistics consistently show that officers are significantly more likely to ask African American or Hispanic motorists or pedestrians for consent to search—but that searches of minorities are in fact less likely to turn up contraband. A 2014 study found that Illinois state troopers were 2.5 times more likely to ask Hispanic motorists for consent to search, but were 2.5 times more likely to find contraband in searches of white motorists. ACLU of Illinois, Racial Disparity in Consent Searches and Dog Sniff Searches: An Analysis of Illinois Traffic Stop Data from 2013 (2014); see also Richard A. Oppel, Jr., Activists Wield Search Data to Challenge and Change Police Policy, N.Y. Times (Nov. 20, 2014) (describing similar findings of disparate impact in Durham, North Carolina, and Austin, Texas). A number of law-enforcement agencies and officials have recognized these risks. For example, the Kalamazoo, Michigan, police department revised its consent-search policy after a commissioned study found that Black motorists were stopped at a rate at least two times greater than white motorists. In explaining the need for the revisions, Chief Jeff Hadley cited the “collateral damage” to community relations caused by previous policies. Aaron Mueller, Traffic Stops by Kalamazoo Police Down by Nearly Half in 6 Months Since Racial Profiling Study, MLive.com (March 3, 2014), http://www.mlive.com/‌news/‌kalamazoo/index.ssf‌/2014/03/racial_profiling_study_prompts.html.

Finally, given that consent searches often are conducted based on little or no suspicion, there is reason to doubt their effectiveness. The hit rates for consent searches generally are low. See, e.g., Illya D. Lichtenberg & Alisa Smith, Testing the Effectiveness of Consent Searches as a Law Enforcement Tool, 14 Justice Professional 95, 102-104 (2001) (finding consent-search hit rates for detection of drugs ranging between 9.4 percent and 22.9 percent over various periods in Maryland and Ohio); Report of the New Jersey Senate Judiciary Committee’s Investigation of Racial Profiling and the New Jersey State Police 86 (2001) (noting that just “37 seizures resulted from the 271 consent searches in the year 2000.”). An Ohio study found that as officers made greater use of consent searches, hit rates went down, which suggests that consent searches are most effective when officers are more discerning in deciding when to use them. Lichtenberg & Smith, supra.

2. The limits of written consent forms. Although a number of jurisdictions have responded to these concerns by requiring officers to obtain consent in writing, there is some reason to doubt that consent forms can fully address the concerns described here. As Nancy Leong and Kira Suyeshi note, “a signed consent form does not signify that a suspect rendered consent voluntarily. The form does little to improve a suspect’s understanding of her rights, particularly when the suspect is poorly educated, frightened, not fluent in English, or otherwise impaired in her ability to understand.” Nancy Leong & Kira Suyeshi, Consent Forms and Consent Formalism, 2013 Wisc. L. Rev. 751, 751 (2013). To the extent that individuals feel singled out by the request itself, a consent-to-search form is unlikely to address those concerns. Finally, there also is some risk that the presence of a signed consent form may dissuade courts from looking sufficiently closely at whether consent was in fact voluntary. Id.

3. Requirement of reasonable suspicion. These Principles urge agencies to limit the use of consent searches to circumstances in which they are likely to turn up evidence of crime—namely, when officers have reasonable suspicion to believe that the target of the search is involved in criminal activity. Absent reasonable suspicion to justify the search, an officer’s request to search is based on little more than a hunch. As Justice Sotomayor has argued, “[w]hen we condone officers’ use of these devices without adequate cause, we give them reason to target pedestrians in an arbitrary manner.” Utah v. Strieff, 136 S. Ct. 2056, 2069 (2016) (Sotomayor, J., dissenting).

Several departments across the United States already have taken this approach. See, e.g., Austin Police Dep’t, Austin PD Policy Manual 145 (2017) (“Officers should . . . only request a consent search when they have an articulable reason why they believe the search is necessary and likely to produce evidence related to an investigation.”); Milwaukee Police Dep’t, Standard Operating Procedure: 085 Citizen Contacts, Field Interviews, Search and Seizure (2014) (same); Mueller, supra(noting a similar policy in Kalamazoo, Michigan). In addition, some state courts have interpreted their state constitutions to require a similar “reasonable suspicion” requirement for consent searches. See State v. Fort, 660 N.W.2d 415, 416 (Minn. 2003) (“[I]n the absence of reasonable, articulable suspicion a consent-based search obtained by exploitation of a routine traffic stop that exceeds the scope of the stop’s underlying justification is invalid.”); State v. Carty, 790 A.2d 903, 905 (N.J. 2002).

4. Additional precautions. Agencies also can take additional steps to ensure that consent searches are used in a manner that is consistent with these Principles. First, agencies should ensure there is a mechanism in place to document that officers in fact sought consent to search. Written consent forms can serve this purpose, but so too can requiring officers to document consent using an audio or video recording. See, e.g., Austin Police Dep’t, Austin PD Policy Manual, supra at 147 (“For consent searches not involving a vehicle or subject stop, an officer with supervisory approval may document the voluntary consent using only video and/or audio recording.”).

A number of agencies also have monitored the use of consent searches by requiring officers to get supervisor approval before conducting a search. New Orleans Police Dep’t, Operations Manual, Chapter 1.2.4 Search and Seizure Policy Statement 20 (2016) (“An officer shall immediately notify a supervisor when considering a search based on consent. Before an officer may conduct a consent search, the officer must have the express approval of his or her supervisor.”); Austin Police Dep’t, Austin PD Policy Manual 145 (2017) (same).

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