534 U.S. 266122 S.Ct. 744151 L.Ed.2d 740
UNITED STATES, PETITIONERv.RALPH ARVIZU
No. 00-1519.
United States Supreme Court
Argued November 27, 2001Decided January 15, 2002

Syllabus
Respondent was stopped by Border Patrol Agent Stoddard while driving on an  unpaved road in a remote area of southeastern Arizona. A search of his vehicle  revealed more than 100 pounds of marijuana, and he was charged with possession  with intent to distribute. The Federal District Court denied respondents motion  to suppress, citing a number of facts that gave Stoddard reasonable suspicion to  stop the vehicle. The Ninth Circuit reversed. In its view, fact-specific  weighing of circumstances or other multi-factor tests introduced uncertainty and  unpredictability into the Fourth Amendment analysis, making it necessary to  clearly delimit the factors that an officer may consider in making stops such as  this one. It then held that several factors relied upon by the District Court  carried little or no weight in the reasonable-suspicion calculus and that the  remaining factors were not enough to render the stop permissible.
Held: Considering the totality of the circumstances and giving due weight to the  factual inferences drawn by Stoddard and the District Court Judge, Stoddard had  reasonable suspicion to believe that respondent was engaged in illegal activity.  Because the balance between the public interest and the individuals right to  personal security, United States v. Brignoni-Ponce, 422 U.S. 873, 878, tilts in  favor of a standard less than probable cause in brief investigatory stops of  persons or vehicles, the Fourth Amendment is satisfied if the officers action is  supported by reasonable suspicion to believe that criminal activity may be  afoot, United States v. Sokolow, 490 U.S. 1, 7. In making reasonable-suspicion  determinations, reviewing courts must look at the totality of the circumstances  of each case to see whether the detaining officer has a particularized and  objective basis for suspecting legal wrongdoing. See, e.g., United States v.  Cortez, 449 U.S. 411, 417418. This process allows officers to draw on their own  experiences and specialized training to make inferences from and deductions  about the cumulative information available. Id., at 418. The Ninth Circuits  methodology departs sharply from these teachings, and it reached the wrong  result in this case. Its evaluation and rejection of certain factors in  isolation from each other does not take into account the totality of the  circumstances, as this Courts cases have understood that phrase. The court  appeared to believe that each of Stoddards observations that was by itself  susceptible to an innocent explanation was entitled to no weight. Terry v. Ohio,  392 U.S. 1, however, precludes this sort of divide-and-conquer analysis. And the  courts view that it was necessary to clearly delimit an officers consideration  of certain factors to reduce troubling uncertainty also runs counter to this  Courts cases and underestimates the reasonable-suspicion standards usefulness in  guiding officers in the field. The de novo standard for appellate review of  reasonable-suspicion determinations has, inter alia, a tendency to unify  precedent and a capacity to provide law enforcement officers the tools to reach  the correct decision beforehand. Ornelas v. United States, 517 U.S. 690, 691,  697698. The Ninth Circuits approach would seriously undermine the totality of  the circumstances principle governing the existence vel non of reasonable  suspicion. Here, it was reasonable for Stoddard to infer from his observations,  his vehicle registration check, and his border patrol experience that respondent  had set out on a route used by drug smugglers and that he intended to pass  through the area during a border patrol shift change; and Stoddard's assessment  of the reactions of respondent and his passengers was entitled to some weight.  Although each of the factors alone is susceptible to innocent explanation, and  some factors are more probative than others, taken together, they sufficed to  form a particularized and objective basis for stopping the vehicle. Pp. 611.  232 F. 3d 1241, reversed and remanded.
Rehnquist, C.J., delivered the opinion for a unanimous Court. Scalia, J.,  filed a concurring opinion.
On writ of certiorari to the united states court of  appeals for the ninth circuit
Chief Justice Rehnquist delivered the opinion of the Court.


1
Respondent Ralph Arvizu was stopped by a border patrol agent while driving  on an unpaved road in a remote area of southeastern Arizona. A search of his  vehicle turned up more than 100 pounds of marijuana. The District Court for the  District of Arizona denied respondents motion to suppress, but the Court of  Appeals for the Ninth Circuit reversed. In the course of its opinion, it  categorized certain factors relied upon by the District Court as simply out of  bounds in deciding whether there was reasonable suspicion for the stop. We hold  that the Court of Appeals methodology was contrary to our prior decisions and  that it reached the wrong result in this case.


2
On an afternoon in January 1998, Agent Clinton Stoddard was working at a  border patrol checkpoint along U.S. Highway 191 approximately 30 miles north of  Douglas, Arizona. App. 22, 24. See Appendix, infra (containing a map of the area  noting the location of the checkpoint and other points important to this case).  Douglas has a population of about 13,000 and is situated on the United  States-Mexico border in the southeastern part of the State. Only two highways  lead north from Douglas. See App. 157. Highway 191 leads north to Interstate 10,  which passes through Tucson and Phoenix. State Highway 80 heads northeast  through less populated areas toward New Mexico, skirting south and east of the  portion of the Coronado National Forest that lies approximately 20 miles  northeast of Douglas.1


3
The checkpoint is located at the intersection of 191 and Rucker Canyon  Road, an unpaved east-west road that connects 191 and the Coronado National  Forest. When the checkpoint is operational, border patrol agents stop the  traffic on 191 as part of a coordinated effort to stem the flow of illegal  immigration and smuggling across the international border. See id., at 2021.  Agents use roving patrols to apprehend smugglers trying to circumvent the  checkpoint by taking the back roads, including those roads through the sparsely  populated area between Douglas and the national forest. Id., at 2122, 26, 80.  Magnetic sensors, or intrusion devices, facilitate agents efforts in patrolling  these areas. See id., at 25. Directionally sensitive, the sensors signal the  passage of traffic that would be consistent with smuggling activities. Ibid.;  Tr. of Oral Arg. 2324.


4
Sensors are located along the only other northbound road from Douglas  besides Highways 191 and 80: Leslie Canyon Road. Leslie Canyon Road runs roughly  parallel to 191, about halfway between 191 and the border of the Coronado  National Forest, and ends when it intersects Rucker Canyon Road. It is unpaved  beyond the 10-mile stretch leading out of Douglas and is very rarely traveled  except for use by local ranchers and forest service personnel. App. 26.  Smugglers commonly try to avoid the 191 checkpoint by heading west on Rucker  Canyon Road from Leslie Canyon Road and thence to Kuykendall Cutoff Road, a  primitive dirt road that leads north approximately 12 miles east of 191. Id., at  2930. From there, they can gain access to Tucson and Phoenix. Id., at 30.


5
Around 2:15 p.m., Stoddard received a report via Douglas radio that a  Leslie Canyon Road sensor had triggered. Id., at 24. This was significant to  Stoddard for two reasons. First, it suggested to him that a vehicle might be  trying to circumvent the checkpoint. Id., at 27. Second, the timing coincided  with the point when agents begin heading back to the checkpoint for a shift  change, which leaves the area un-patrolled. Id., at 26, 47. Stoddard knew that  alien smugglers did extensive scouting and seemed to be most active when agents  were en route back to the checkpoint. Another border patrol agent told Stoddard  that the same sensor had gone off several weeks before and that he had  apprehended a minivan using the same route and witnessed the occupants throwing  bundles of marijuana out the door. Id., at 27.


6
Stoddard drove eastbound on Rucker Canyon Road to investigate. As he did  so, he received another radio report of sensor activity. Id., at 29. It  indicated that the vehicle that had triggered the first sensor was heading  westbound on Rucker Canyon Road. He continued east, passing Kuykendall Cutoff  Road. He saw the dust trail of an approaching vehicle about a half mile away.  Id., at 31. Stoddard had not seen any other vehicles and, based on the timing,  believed that this was the one that had tripped the sensors. Id., at 3132. He  pulled off to the side of the road at a slight slant so he could get a good look  at the oncoming vehicle as it passed by. Id., at 32.


7
It was a minivan, a type of automobile that Stoddard knew smugglers used.  Id., at 33. As it approached, it slowed dramatically, from about 5055 to 2530  miles per hour. Id., at 32, 57. He saw five occupants inside. An adult man was  driving, an adult woman sat in the front passenger seat, and three children were  in the back. Id., at 3334. The driver appeared stiff and his posture very rigid.  He did not look at Stoddard and seemed to be trying to pretend that Stoddard was  not there. Id., at 33. Stoddard thought this suspicious because in his  experience on patrol most persons look over and see what is going on, and in  that area most drivers give border patrol agents a friendly wave. Id., at 59.  Stoddard noticed that the knees of the two children sitting in the very back  seat were unusually high, as if their feet were propped up on some cargo on the  floor. Id., at 34.


8
At that point, Stoddard decided to get a closer look, so he began to follow  the vehicle as it continued westbound on Rucker Canyon Road toward Kuykendall  Cutoff Road. Id., at 3435. Shortly thereafter, all of the children, though still  facing forward, put their hands up at the same time and began to wave at  Stoddard in an abnormal pattern. Id., at 35, 61. It looked to Stoddard as if the  children were being instructed. Their odd waving continued on and off for about  four to five minutes. Id., at 35, 73.


9
Several hundred feet before the Kuykendall Cutoff Road intersection, the  driver signaled that he would turn. Id., at 36. At one point, the driver turned  the signal off, but just as he approached the intersection he put it back on and  abruptly turned north onto Kuykendall. The turn was significant to Stoddard  because it was made at the last place that would have allowed the minivan to  avoid the checkpoint. Id., at 37. Also, Kuykendall, though passable by a sedan  or van, is rougher than either Rucker Canyon or Leslie Canyon roads, and the  normal traffic is four-wheel-drive vehicles. Id., at 36, 6364. Stoddard did not  recognize the minivan as part of the local traffic agents encounter on patrol,  id., at 37, and he did not think it likely that the minivan was going to or  coming from a picnic outing. He was not aware of any picnic grounds on Turkey  Creek, which could be reached by following Kuykendall Cutoff all the way up.  Id., at 54. He knew of picnic grounds and a Boy Scout camp east of the  intersection of Rucker Canyon and Leslie Canyon roads, id., at 31, 53, 54, but  the minivan had turned west at that intersection. And he had never seen anyone  picnicking or sightseeing near where the first sensor went off. Id., at 53, 75.


10
Stoddard radioed for a registration check and learned that the minivan was  registered to an address in Douglas that was four blocks north of the border in  an area notorious for alien and narcotics smuggling. Id., at 3738, 6667. After  receiving the information, Stoddard decided to make a vehicle stop. Id., at 38.  He approached the driver and learned that his name was Ralph Arvizu. Stoddard  asked if respondent would mind if he looked inside and searched the vehicle.  Id., at 43. Respondent agreed, and Stoddard discovered marijuana in a black  duffel bag under the feet of the two children in the back seat. Id., at 4546.  Another bag containing marijuana was behind the rear seat. Id., at 46. In all,  the van contained 128.85 pounds of marijuana, worth an estimated $99,080. Brief  for United States 8.


11
Respondent was charged with possession with intent to distribute marijuana  in violation of 21 U.S.C. 841(a)(1) (1994 ed.). He moved to suppress the  marijuana, arguing among other things that Stoddard did not have reasonable  suspicion to stop the vehicle as required by the Fourth Amendment. After holding  a hearing where Stoddard and respondent testified, the District Court for the  District of Arizona ruled otherwise. App. to Pet. for Cert. 21a. It pointed to a  number of the facts described above and noted particularly that any recreational  areas north of Rucker Canyon would have been accessible from Douglas via 191 and  another paved road, making it unnecessary to take a 40-to-50-mile trip on dirt  roads. Id., at 22a.


12
The Court of Appeals for the Ninth Circuit reversed. 232 F.3d 1241 (2000).  In its view, fact-specific weighing of circumstances or other multi factor tests  introduced a troubling degree of uncertainty and unpredictability into the  Fourth Amendment analysis. Id., at 1248 (internal quotation marks omitted). It  therefore attempt[ed] to describe and clearly delimit the extent to which  certain factors may be considered by law enforcement officers in making stops  such as the stop involv[ing] respondent. Ibid. After characterizing the District  Courts analysis as relying on a list of 10 factors, the Court of Appeals  proceeded to examine each in turn. It held that 7 of the factors, including  respondents slowing down, his failure to acknowledge Stoddard, the raised  position of the children's knees, and their odd waving carried little or no  weight in the reasonable-suspicion calculus. The remaining factors the roads use  by smugglers, the temporal proximity between respondents trip and the agents  shift change, and the use of minivans by smugglers were not enough to render the  stop permissible. Id., at 1251. We granted certiorari to review the decision of  the Court of Appeals because of its importance to the enforcement of federal  drug and immigration laws. 532 U.S. 1065 (2001).


13
The Fourth Amendment prohibits unreasonable searches and seizures by the  Government, and its protections extend to brief investigatory stops of persons  or vehicles that fall short of traditional arrest. Terry v. Ohio, 392 U.S. 1, 9  (1968); United States v. Cortez, 449 U.S. 411, 417 (1981). Because the balance  between the public interest and the individuals right to personal security,  United States v. Brignoni-Ponce, 422 U.S. 873, 878 (1975), tilts in favor of a  standard less than probable cause in such cases, the Fourth Amendment is  satisfied if the officers action is supported by reasonable suspicion to believe  that criminal activity may be afoot, United States v. Sokolow, 490 U.S. 1, 7  (1989) (quoting Terry, supra, at 30). See also Cortez, 449 U.S., at 417 (An  investigatory stop must be justified by some objective manifestation that the  person stopped is, or is about to be, engaged in criminal activity).


14
When discussing how reviewing courts should make reasonable-suspicion  determinations, we have said repeatedly that they must look at the totality of  the circumstances of each case to see whether the detaining officer has a  particularized and objective basis for suspecting legal wrongdoing. See, e.g.,  id., at 417-418. This process allows officers to draw on their own experience and  specialized training to make inferences from and deductions about the cumulative  information available to them that might well elude an untrained person. Id., at  418. See also Ornelas v. United States, 517 U.S. 690, 699 (1996) (reviewing  court must give due weight to factual inferences drawn by resident judges and  local law enforcement officers). Although an officers reliance on a mere hunch  is insufficient to justify a stop, Terry, supra, at 27, the likelihood of  criminal activity need not rise to the level required for probable cause, and it  falls considerably short of satisfying a preponderance of the evidence standard,  Sokolow, supra, at 7.


15
Our cases have recognized that the concept of reasonable suspicion is  somewhat abstract. Ornelas, supra, at 696 (principle of reasonable suspicion is  not a finely-tuned standar[d]); Cortez, supra, at 417 (the cause sufficient to  authorize police to stop a person is an elusive concept). But we have  deliberately avoided reducing it to a neat set of legal rules, Ornelas, supra,  at 695696 (quoting Illinois v. Gates, 462 U.S. 213, 232 (1983)). In Sokolow, for  example, we rejected a holding by the Court of Appeals that distinguished  between evidence of ongoing criminal behavior and probabilistic evidence because  it create[d] unnecessary difficulty in dealing with one of the relatively simple  concepts embodied in the Fourth Amendment. 490 U.S., at 78.


16
We think that the approach taken by the Court of Appeals here departs  sharply from the teachings of these cases. The courts evaluation and rejection  of seven of the listed factors in isolation from each other does not take into  account the totality of the circumstances, as our cases have understood that  phrase. The court appeared to believe that each observation by Stoddard that was  by itself readily susceptible to an innocent explanation was entitled to no  weight. See 232 F.3d, at 1249-1251. Terry, however, precludes this sort of  divide-and-conquer analysis. The officer in Terry observed the petitioner and  his companions repeatedly walk back and forth, look into a store window, and  confer with one another. Although each of the series of acts was perhaps  innocent in itself, we held that, taken together, they warranted further  investigation. 392 U.S., at 22. See also Sokolow, supra, at 9 (holding that  factors which by themselves were quite consistent with innocent travel  collectively amounted to reasonable suspicion).


17
The Court of Appeals view that it was necessary to clearly delimit an  officers consideration of certain factors to reduce troubling uncertainty, 232  F.3d, at 1248, also runs counter to our cases and underestimates the usefulness  of the reasonable-suspicion standard in guiding officers in the field. In  Ornelas v. United States, we held that the standard for appellate review of  reasonable-suspicion determinations should be de novo, rather than for abuse of  discretion. 517 U.S., at 691. There, we reasoned that de novo review would  prevent the affirmance of opposite decisions on identical facts from different  judicial districts in the same circuit, which would have been possible under the  latter standard, and would allow appellate courts to clarify the legal  principles. Id., at 697. Other benefits of the approach, we said, were its  tendency to unify precedent and greater capacity to provide law enforcement  officers with the tools to reach correct determinations beforehand: Even if in  many instances the factual mosaic analyzed for a reasonable-suspicion  determination would preclude one case from squarely controlling another, two  decisions when viewed together may usefully add to the body of law on the  subject. Id., at 697698.


18
But the Court of Appeals approach would go considerably beyond the  reasoning of Ornelas and seriously undercut the totality of the circumstances  principle which governs the existence vel non of reasonable suspicion. Take, for  example, the courts positions that respondents deceleration could not be  considered because slowing down after spotting a law enforcement vehicle is an  entirely normal response that is in no way indicative of criminal activity and  that his failure to acknowledge Stoddard's presence provided no support because  there were no special circumstances rendering innocent avoidance improbable. 232  F.3d, at 12481249. We think it quite reasonable that a drivers slowing down,  stiffening of posture, and failure to acknowledge a sighted law enforcement  officer might well be unremarkable in one instance (such as a busy San Francisco  highway) while quite unusual in another (such as a remote portion of rural  southeastern Arizona). Stoddard was entitled to make an assessment of the  situation in light of his specialized training and familiarity with the customs  of the areas inhabitants. See Ornelas, supra, at 699. To the extent that a  totality of the circumstances approach may render appellate review less  circumscribed by precedent than otherwise, it is the nature of the totality  rule.


19
In another instance, the Court of Appeals chose to dismiss entirely the  children's waving on grounds that odd conduct by children was all too common to  be probative in a particular case. See 232 F.3d, at 1249 (If every odd act  engaged in by ones children could contribute to a finding of reasonable  suspicion, the vast majority of American parents might be stopped regularly  within a block of their homes). Yet this case did not involve simply any odd act  by children. At the suppression hearing, Stoddard testified about the children's  waving several times, and the record suggests that he physically demonstrated it  as well.2 The District Court Judge, who saw and heard Stoddard, then  characterized the waving as methodical, mechanical, abnormal, and certainly a  fact that is odd and would lead a reasonable officer to wonder why they are  doing this. App. to Pet. for Cert. 25a. Though the issue of this case does not  turn on the children's idiosyncratic actions, the Court of Appeals should not  have casually rejected this factor in light of the District Courts superior  access to the evidence and the well-recognized inability of reviewing courts to  reconstruct what happened in the courtroom.


20
Having considered the totality of the circumstances and given due weight to  the factual inferences drawn by the law enforcement officer and District Court  Judge, we hold that Stoddard had reasonable suspicion to believe that respondent  was engaged in illegal activity. It was reasonable for Stoddard to infer from  his observations, his registration check, and his experience as a border patrol  agent that respondent had set out from Douglas along a little-traveled route  used by smugglers to avoid the 191 checkpoint. Stoddard's knowledge further  supported a commonsense inference that respondent intended to pass through the  area at a time when officers would be leaving their back roads patrols to change  shifts. The likelihood that respondent and his family were on a picnic outing  was diminished by the fact that the minivan had turned away from the known  recreational areas accessible to the east on Rucker Canyon Road. Corroborating  this inference was the fact that recreational areas farther to the north would  have been easier to reach by taking 191, as opposed to the 40-to-50-mile trip on  unpaved and primitive roads. The children's elevated knees suggested the  existence of concealed cargo in the passenger compartment. Finally, for the  reasons we have given, Stoddards assessment of respondents reactions upon seeing  him and the children's mechanical-like waving, which continued for a full four to  five minutes, were entitled to some weight.


21
Respondent argues that we must rule in his favor because the facts  suggested a family in a minivan on a holiday outing. A determination that  reasonable suspicion exists, however, need not rule out the possibility of  innocent conduct. See Illinois v. Wardlow, 528 U.S. 119, 125 (2000) (that flight  from police is not necessarily indicative of ongoing criminal activity does not  establish Fourth Amendment violation). Undoubtedly, each of these factors alone  is susceptible to innocent explanation, and some factors are more probative than  others. Taken together, we believe they sufficed to form a particularized and  objective basis for Stoddards stopping the vehicle, making the stop reasonable  within the meaning of the Fourth Amendment.


22
The judgment of the Court of Appeals is therefore reversed, and the case is  remanded for further proceedings consistent with this opinion.


23
It is so ordered.



Notes:


1
       GRAPHIC OMITTED; SEE PRINTED OPINION. Coronado National Forest consists of  12 widely scattered sections of land covering 1,780,000 acres in southeastern  Arizona and southwestern New Mexico. The section of the forest near Douglas  includes the Chiricahua, Dragoon, and Peloncillo Mountain Ranges.


2
  At one point during the hearing, Stoddard testified that [the children's waving]  wasn't in a normal pattern. It looked like they were instructed to do so. They  kind of stuck their hands up and began waving to me like this. App. 35.



24
Justice Scalia, concurring.


25
I join the opinion of the Court, because I believe it accords with our  opinion in Ornelas v. United States, 517 U.S. 690, 699 (1996), requiring de novo  review which nonetheless gives due weight to inferences drawn from [the] facts  by resident judges . . . . As I said in my dissent in Ornelas, however, I do not  see how deferring to the District Courts factual inferences (as opposed to its  findings of fact) is compatible with de novo review. Id., at 705.


26
The Court today says that due weight should have been given to the District  Courts determinations that the children's waving was methodical, mechanical,  abnormal, and certainly . . . a fact that is odd and would lead a reasonable  officer to wonder why they are doing this. Ante, at 10. Methodical, mechanical,  and perhaps even abnormal and odd, are findings of fact that deserve respect.  But the inference that this would lead a reasonable officer to wonder why they  are doing this, amounts to the conclusion that their action was suspicious,  which I would have thought (if de novo review is the standard) is the  prerogative of the Court of Appeals. So we have here a peculiar sort of de novo  review.


27
I may add that, even holding the Ninth Circuit to no more than the  traditional methodology of de novo review, its judgment here would have to be  reversed.

