¶ 1. This case involves a consent search of a vehicle, and the issue is whether the driver was "seized" for purposes of the Fourth Amendment when he consented to the search.
¶ 2. Defendant Lawrence Williams was stopped for speeding on 1-94. The state trooper conducting the stop issued a warning citation and returned Williams' driver's license and other paperwork, said "[wej'll let you get on your way then," shook hands, and headed back to his squad car. After two steps, the trooper abruptly turned around and began questioning Williams about whether he had any guns, knives, drugs, or large amounts of money in the car, and asked for permission to search. Williams denied having any of the items in question, and gave consent to search. The trooper found heroin and a gun.
¶ 3. Williams and his passenger, Antwon Mathews, were charged with possession of heroin with intent to deliver and carrying a concealed weapon. The circuit court suppressed the physical evidence recovered in the search, concluding that Williams' consent *5was invalid because his continued detention after the traffic stop had concluded was illegal. The state appealed, and the court of appeals affirmed. We accepted review, and now reverse.
¶ 4. The question of whether a police contact is a "seizure" under the Fourth Amendment is determined by reference to an objective test. "[A] person has been 'seized' within the meaning of the Fourth Amendment only if, in view of all of the circumstances surrounding the incident, a reasonable person would have believed that he was not free to leave." United States v. Mendenhall, 446 U.S. 544, 554 (1980). Here, the traffic stop that immediately preceded Williams' consent was over, and he had been told unequivocally that he was free to leave. The trooper's subsequent questioning did not constitute a new seizure. Accordingly, Williams’ consent to the vehicle search was not invalid as a result of an illegal seizure. The drugs and the gun should not have been suppressed.
HH
¶ 5. The facts are from the complaint, the suppression hearing, the state trooper's incident report, and a videotape of the traffic stop, the latter two items having been admitted into evidence at the suppression hearing.1 At approximately 2:30 a.m. on June 7, 2000, State Trooper James Fetherston was patrolling 1-94 in Eau Claire County when he observed a vehicle approaching him rapidly. Fetherston allowed the vehicle to pass, clocked it at 78.7 m.p.h., activated his emergency flashing lights, and pulled the car over for speeding.
*6¶ 6. Lawrence Williams was the driver and Ant-won Mathews was his front-seat passenger. Fetherston approached the driver's side window, explained that he had stopped the car for speeding, and asked Williams for his driver's license. He then asked Williams whose car he was driving. Williams replied that it was a rental car and that he did not know who the renter was. Mathews told the officer that the car had been rented by his uncle. Williams produced the rental papers and gave them to Fetherston. During this exchange, Williams appeared very nervous, was breathing very fast, and would not make eye contact with the trooper.
¶ 7. Fetherston told Williams and Mathews to "sit tight for a minute," and returned to his patrol car to call in Williams' license. He also requested back-up, saying he had "a Badger going." This particular state patrol terminology, no longer in use, refers to a law enforcement interdiction technique by which the officer attempts to obtain the driver's consent to search the vehicle.
¶ 8. The dispatcher reported that Williams' license was valid and the vehicle was not stolen, but alerted Fetherston that Williams had come up a "ten-zero" on prior offenses, which Fetherston testified meant "caution." At some point during this process, Fetherston turned off his squad's emergency lights. Eau Claire County Sheriffs Deputy Jonathan Staber arrived as backup, parking his squad behind Fetherston's and leaving his emergency lights activated. Both officers then walked towards Williams' car, Staber on the passenger side, and Fetherston on the driver's side.
¶ 9. Fetherston asked Williams to step out of the car. While standing with Williams at the rear of the car, Fetherston pointed out that the rental agreement did not allow Williams to be driving. Williams said he was *7unaware of that fact. Fetherston then returned Williams' driver's license and the rental papers, and indicated he was going to issue a warning for speeding. He showed Williams the warning citation and said, "This is a warning for speeding, need a signature and we'll get you on your way then." The tone throughout, on both sides, was polite and conversational.
¶ 10. During this exchange, Staber, the back-up officer, was standing next to the passenger side of Williams' car. He held a flashlight in his right hand illuminating the inside of the vehicle, and generally kept his left hand resting on the front of his belt.
¶ 11. Williams signed the warning citation. Fetherston handed it to him and asked if he had any questions. Williams stated that he did not, that he was familiar with the state patrol, and knew how everything worked. The officer replied, "Good, we'll let you get on your way then okay."
¶ 12. Williams extended his hand to the officer and said, "Okay. You have a good day." They shook hands, and Fetherston said, "Take care. We'll see you." Williams turned around and took a couple of steps towards his car. Fetherston turned toward his squad, took a step or two, then abrúptly swiveled back around and in a louder but still conversational tone said, "Hey Lawrence." Williams turned back to face Fetherston, replying, "Yes, sir?" Then, in a rapid succession of questions, Fetherston asked Williams about any contraband he and/or Mathews might be carrying:
Fetherston (Q): There's no guns in the car is there?
Williams (A): No, sir.
Q: Any knives?
A: No, sir.
*8Q: How about any drugs? You guys got any drugs in there?
A: No, sir.
Q: Any large amounts of money? You guys bringing, not bringing, back any big quantities of money ...
A: No.
Q: ... from ...
A: No.
Q: May I search your car just to be sure those items that 1 mentioned are not in there?
A: Yes, sir.
Q: That's fine?
A: Yes, sir.
¶ 13. Mathews, an amputee, was then asked to step out of the car. The officer assisted Mathews with his crutches, and Mathews engaged him in a friendly, detailed conversation about a prosthesis he was hoping to get and a lawsuit he was pursuing over how he lost his leg. Fetherston then searched the car and found a loaded handgun and heroin. Williams and Mathews were arrested and charged with possession of heroin with intent to deliver and carrying a concealed weapon, as party to the crime, contrary to Wis. Stat. §§ 961.41(lm)(d)3, 941.23, and 939.05 (1999-2000).2
*9¶ 14. Williams moved to suppress the evidence obtained in the search of his vehicle.3 The Eau Claire County Circuit Court, the Honorable Benjamin D. Proctor, granted the motion.
f 15. The circuit court concluded that Fetherston needed new, separate, and sufficient "reasonable suspicion" to support any further investigation beyond the original traffic stop, and here, all the officer had was "mere curiosity," such that his request for permission to search was just "a shot in the dark." The court held that "[i]t is unreasonable to suspect that under those circumstances any citizen would think that he or she had a right to be uncooperative in the presence of two law enforcement officers at 2:30 in the morning and that any reasonable citizen under those circumstances would think that uncooperativeness might be just cause for further detention. It cannot be expected that every citizen he a lawyer."
¶ 16. The State appealed,4 and the court of appeals affirmed. State v. Williams, 2001 WI App 249, 248 Wis. 2d 361, 635 N.W.2d 869. Applying the Mendenhall test, the court concluded that Williams was "seized" within the meaning of the Fourth Amendment at the time he consented to the search. The court emphasized that its conclusion was based on the totality of the circumstances — including, in particular, the rapid succession of questions, the more abrupt and slightly *10louder tone, the presence and. stance of the back-up officer, the flashing emergency lights of the second squad, the location (a rural interstate highway), and the time of night (2:30 a.m.). Williams, 2001 WI App 249, ¶ 19. In this situation, the court held, a reasonable person "would not have felt free to disregard the questions and walk away." Id.
HH HH
¶ 17. This case presents a question of constitutional fact subject to a two-part standard of review. State v. Matejka, 2001 WI 5, ¶ 16, 241 Wis. 2d 52, 621 N.W.2d 891; see also State v. Griffith, 2000 WI 72, ¶ 23, 236 Wis. 2d 48, 58, 613 N.W.2d 72. The circuit court's findings of evidentiary or historical fact are upheld unless clearly erroneous. Matejka, 2001 WI 5, ¶ 16. The determination of whether Williams was "seized" for Fourth Amendment purposes is reviewed de novo. Id.
¶ 18. Warrentless searches are per se unreasonable under the Fourth Amendment.5 Katz v. United States, 389 U.S. 347, 357 (1967). But there are certain "specifically established and well-delineated" exceptions *11to the Fourth Amendment's warrant requirement. Id. Included among these exceptions are searches conducted pursuant to voluntarily given consent. Id. at 358; State v. Phillips, 218 Wis. 2d 180, 196, 577 N.W.2d 794 (1998).
¶ 19. A "search authorized by consent is wholly valid" under the Fourth Amendment. Schneckloth v. Bustamonte, 412 U.S. 218, 222 (1973). Consent searches are standard, accepted investigative devices used in law enforcement, and are not in any general sense constitutionally suspect. Id. at 231-32, 243.
¶ 20. The defendants contend, and the lower courts held, that the consent to search in this case was invalid because Williams was illegally "seized" when he gave it. Not all encounters with law enforcement officers are "seizures" within the meaning of the Fourth Amendment. Florida v. Bostick, 501 U.S. 429, 434 (1991); State v. Kelsey C.R., 2001 WI 54, ¶ 30, 243 Wis. 2d 422, 442, 626 N.W.2d 777. The general rule is that a seizure has occurred when an officer, "by means of physical force or show of authority, has in some way restrained the liberty of a citizen . ..." Mendenhall, 446 U.S. at 552 (quoting Terry v. Ohio, 392 U.S. 1, 19, n.16 (1968)); State v. Harris, 206 Wis. 2d 243, 253, 557 N.W.2d 245 (1996).
¶ 21. The Mendenhall test for determining whether a particular police contact constitutes a seizure for purposes of the Fourth Amendment was adopted by the United States Supreme Court in INS v. Delgado, 466 U.S. 210, 215 (1984), and Michigan v. Chesternut, 486 U.S. 567, 573 (1988), and derives from Justice Stewart's lead opinion in the Mendenhall case:
*12We conclude that a person has been "seized" within the meaning of the Fourth Amendment only if, in view of all of the circumstances surrounding the incident, a reasonable person would have believed that he was not free to leave. Examples of circumstances that might indicate a seizure, even where the person did not attempt to leave, would be the threatening presence of several officers, the display of a weapon by an officer, some physical touching of the person of the citizen, or the use of language or tone of voice indicating that compliance with the officer's request might be compelled. ... In the absence of some such evidence, otherwise inoffensive contact between a member of the public and the police cannot, as a matter of law, amount to a seizure of that person.
Mendenhall, 446 U.S. at 554-55 (citations omitted); see also California v. Hodari D., 499 U.S. 621, 627-28 (1991).
¶ 22. Questioning by law enforcement officers does not alone effectuate a seizure. "[P]olice questioning, by itself, is unlikely to result in a Fourth Amendment violation." Delgado, 466 U.S. at 216. Unless the surrounding conditions "are so intimidating as to demonstrate that a reasonable person would have believed he was not free to leave if he had not responded, one cannot say that the questioning resulted in a detention under the Fourth Amendment."6 Delgado, 466 U.S. at *13216; see also Griffith, 2000 WI 72, ¶ 39. "As long as the person to whom the questions are put remains free to disregard the questions and walk away, there has been no intrusion upon that person's liberty or privacy as would under the Constitution require some particular and objective justification." Mendenhall, 446 U.S. at 554.
¶ 23. The Mendenhall test for determining whether a seizure has occurred "is necessarily imprecise because it is designed to assess the coercive effect of police conduct, taken as a whole, rather than to focus on particular details of that conduct in isolation." Chesternut, 486 U.S. at 573. The test is an objective one, focusing not on whether the defendant himself felt free to leave but whether a reasonable person, under all the circumstances, would have felt free to leave. Hodari D., 499 U.S. at 628; Chesternut, 486 U.S. at 574. "[T]he 'reasonable person' test presupposes an innocent person." Bostick, 501 U.S. at 438. While it is true that "most citizens will respond to a police request, the fact that people do so, and do so without being told they are free not to respond, hardly eliminates the consensual nature of the response."7 Delgado, 466 U.S. at 216.
¶ 24. The Supreme Court has very recently added to its "seizure" jurisprudence in United States v. Drayton, 536 U.S. 194, 122 S.Ct. 2105 (2002). Drayton *14involved the issue of drug and weapons interdiction on buses. Id. at 2108. The defendants were passengers on a Greyhound bus. At a scheduled stop in Tallahasse, the bus was boarded by local police, who proceeded to question the passengers and ask for consent to search their luggage. Id. at 2109. The defendants were questioned, gave consent to searches of their luggage and persons, and were found to be carrying cocaine. Id. at 2110.
¶ 25. The Supreme Court concluded that the defendants were not "seized" for purposes of the Fourth Amendment. Id. Citing Bostick, the Court held that "[e]ven when law enforcement officers have no basis for suspecting a particular individual, they may pose questions, ask for identification, and request consent to search luggage — provided they do not induce cooperation by coercive means." Id. The Court noted that the officers were armed and displayed their badges, and that one of them positioned himself at the front of the bus, but that their conduct was otherwise not intimidating — no guns were drawn, no commands issued, no show of force made. Id. at 2112. Accordingly, the Court held that the circumstances did not amount to a seizure. Id.
¶ 26. It is quite clear based upon the established evidentiary facts in this case that the traffic stop had concluded before Fetherston questioned Williams about contraband in the car and asked for permission to search. Fetherston told Williams he would be free to go after he signed the warning citation; Williams did so, and the citation was handed to him. Fetherston had already returned Williams' driver's license and rental papers. Fetherston said, unequivocally, ”[w]e'll let you get on your way then okay." Fetherston and Williams *15shook hands and exchanged common parting pleasantries ("have a good day" and "take care, we'll see you"), and turned away from each other, at least momentarily.
¶ 27. Indeed, the circuit court made the following finding: "it is clear that, at least verbally, the trooper had given the defendant permission to be on his way." Accordingly, the court of appeals properly focused its analysis on the events at the conclusion of the initial seizure, and immediately thereafter.8 Like the court of appeals, we see the case as calling for a determination of whether Williams was seized after the conclusion of the original traffic stop, when he was questioned about contraband and asked for permission to search.
¶ 28. This requires, as noted above, consideration of all the circumstances and application of an objective "reasonable person" standard. We know that questioning alone does not a seizure make, and the fact that this defendant — perhaps like most people — spontaneously and voluntarily responded to the officer's questions is *16not enough to transform an otherwise consensual exchange into an illegal seizure. Delgado, 466 U.S. at 216; Drayton, 536 U.S. at _, 122 S.Ct. at 2112-13. We conclude that a reasonable person in these circumstances would not have considered himself compelled to stay and answer the officer's questions. Stated positively, a reasonable person would have felt free to decline to answer the officer's questions and simply "get on [his] way."
¶ 29. That the officer had just invited Williams to "get on [his] way" strongly influences our conclusion. The officer's words and actions, considered as a whole, communicated permission to leave, as the traffic stop was over. The officer did nothing, verbally or physically, to compel Williams to stay. That Williams stayed, and answered the questions, and gave consent to search, is not constitutionally suspect, and does not give rise to an inference that he must have been compelled to do so. Mendenhall specifically rejected this argument. Mendenhall, 446 U.S. at 555-56.
¶ 30. The court of appeals was persuaded that the following circumstances combined to constitute a seizure: the tone, tenor, and rapidity of Fetherston's questioning; the presence and stance of the back-up officer, whose squad lights were still flashing; the location; and the time of night. We disagree.
¶ 31. It is true that Fetherston's questions came hard on the heels of the conclusion of the traffic stop, and that he used a somewhat louder and more assertive tone. But apart from the "Hey, Lawrence," which was spoken at a higher volume, the officer essentially continued to maintain a normal speaking voice. The questions were not accusatory in nature. The exchange was largely non-confrontational; indeed, there was sympathetic small talk as Mathews was being assisted with *17his crutches immediately after consent to search was granted. The change in tone and tenor was not so significant in degree that the officer's questions took on the character of an official command, suggesting that compliance was required.
¶ 32. Furthermore, the presence and behavior of the back-up officer was not so intimidating as to convert this consensual exchange into a seizure. Staber stood nearby, on the passenger side of Williams' car, with a flashlight in his right hand and his left hand resting on his belt. That his left hand was therefore near his weapon is not remarkable, unless we are willing to say that the mere presence of an armed back-up officer always tips the scales toward a finding of a seizure. See Drayton, 536 U.S. at_, 122 S.Ct. at 2112 ("That most law enforcement officers are armed is a fact well known to the public. The presence of a holstered firearm thus is unlikely to contribute to the coerciveness of the encounter absent active brandishing of the weapon."). Mendenhall made reference to the "threatening presence of several officers," the "display of a weapon by an officer," or the "physical touching of the person of the citizen" as factors suggesting that compliance with an officer's request is required. Here, the officers did not display their weapons or physically touch Williams, nor can their presence be characterized as "threatening."
¶ 33. That the emergency lights on Staber's squad were activated does not make a significant difference. Staber's squad was parked behind Fetherston's, and Fetherston's emergency lights were off. In any event, officers conducting traffic stops often leave their emergency lights on until everyone has left the scene, presumably for reasons of safety. This factor does not suggest that Williams was required to remain after the traffic stop had concluded.
*18¶ 34. Finally, the location and time of night did not materially contribute to a coercive atmosphere so as to transform the officer's questioning into a seizure. True, it was 2:30 in the morning on a rural section of the interstate. But there was plenty of traffic, so the situation was not as isolating and desolate as it might otherwise seem. Besides, it is not entirely clear why police questioning on the shoulder of a rural interstate at night should be considered inherently more coercive than police questioning in other situations. The suggestion is made that fear of unscrupulous or illegal police tactics is necessarily heightened under these circumstances; we decline to elevate this subjective suggestion to objective status under the "reasonable person" test.
¶ 35. Accordingly, we conclude that the totality of the circumstances establish that a reasonable person would have felt free to decline the officer's questions and leave the scene, or otherwise terminate the encounter. Williams was free to leave when Fetherston returned his driver's license and rental paperwork, gave him the warning citation, and said "we'll let you get on your way then okay." Fetherston's subsequent questioning, considered in the context of all the circumstances and against the objective, "reasonable person" standard, did not constitute a seizure for purposes of the Fourth Amendment. Accordingly, Williams' consent to the vehicle search was not invalid, and the evidence obtained in the search should not have been suppressed. The decision of the court of appeals is reversed.
By the Court. — The decision of the court of appeals is reversed.
The court has viewed the videotape.
All future references to the Wisconsin Statutes will be to the 1999-2000 version unless otherwise stated.
Although Mathews did not file a separate motion, his counsel participated in the suppression hearing and the circuit court's order pertained to both Williams' case and Mathews' case. Prior to the State's appeal, the parties entered into a stipulation preserving Mathews' rights for purposes of this appeal.
The court of appeals granted the State's motion to consolidate Williams' and Mathews' appeals.
The Fourth Amendment protects "[t]he right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures ...." U.S. Const. Amend. IV Article I, Section 11 of the Wisconsin Constitution is nearly identical, and states in relevant part: "The right of the people to be secure in their persons, houses, papers, and effects against unreasonable searches and seizures ..." This court has generally followed the United States Supreme Court's Fourth Amendment jurisprudence when interpreting the Wisconsin Constitution's parallel provision. State v. Matejka, 2001 WI 5, ¶ 17 n.2, 241 Wis. 2d 52, 621 N.W.2d 891.
If a person is not free to leave due to circumstances unrelated to the presence of an officer, then the proper inquiry is whether the totality of the circumstances establishes that a reasonable person "would feel free to decline the officers' requests or otherwise terminate the encounter." Florida v. Bostick, 501 U.S. 429, 436 (1991) (applying the above inquiry where the individual did not feel free to leave because the bus in which he was sitting was about to depart).
Although the defendants do not argue voluntariness here, we note that there is no Fourth Amendment requirement that consent searches be preceded by a warning that the subject has a right to refuse or is free to go in order for the consent to be recognized as voluntary. Ohio v. Robinette, 519 U.S. 33, 39-40 (1996); see also Schneckloth v. Bustamonte, 412 U.S. 218, at 232-33 (1973). This principle was just affirmed in United States v. Drayton, 536 U.S. 194, 122 S.Ct. 2105, 2113 (2002).
This case does not, therefore, present a question of whether the officer impermissibly exceeded the scope of or prolonged the initial seizure in violation of the Fourth Amendment. See State v. Griffith, 2000 WI 72, 236 Wis. 2d 48, 613 N.W.2d 72 (noting that a reasonable seizure can become an unreasonable one if the officer's investigation extends beyond that which is related to the purpose of the stop, but holding that mere identification questions asked of a passenger do not malee a seizure unreasonable); State v. Betow, 226 Wis. 2d 90, 94, 593 N.W.2d 499 (Ct. App. 1999) (holding that "the scope of the officer's inquiry, or the line of questioning, may be broadened beyond the purpose for which the person was stopped only if additional suspicious factors come to the officer's attention ...."); State v. Gaulrapp, 207 Wis. 2d 600, 558 N.W.2d 696 (Ct. App. 1996) (traffic stop not unreasonably prolonged by question about contraband in the car and subsequent request for consent to search).