A judge of the District Court granted the defendant’s motion to suppress evidence that came into plain view when a police officer, believing that the defendant might, be under the influence of narcotics, ordered him to step out of his parked vehicle. The Appeals Court reversed, ruling that the police officer’s order was reasonable in the circumstances. Commonwealth v. Murdough, 44 Mass. App. Ct. 736, 740 (1998). *761We granted the defendant’s application for further appellate review and reverse the judgment of the District Court.
I
The defendant was parked alone in a rest area of an interstate highway on a bright, cold January morning. Two State troopers, who had seen the same vehicle earlier that morning, pulled into the rest area. The defendant’s was the only vehicle in the rest area. The officers noticed that the vehicle’s brake lights were on and that the defendant was asleep. The officers both approached the vehicle and one of them knocked on the window several times. It required two or three minutes of knocking before the defendant awoke, rolled down his window and asked what the officers wanted. The defendant was disheveled and was not wearing shoes. He was asked to show his license and registration. He produced a valid license, but said he did not know where the registration was. When asked who owned the vehicle, the defendant answered, “Scott.” By checking the registration plate, one of the officers confirmed that the registered owner’s first name was Scott, but the judge did not find when this was ascertained. While the officer was talking to him, the defendant became incoherent and fell asleep. The officer again awakened him and told him to get out of the vehicle. The defendant was unsteady and appeared dazed. As the defendant got out of the vehicle, some marihuana and cocaine came into plain view. The defendant was arrested for possession of controlled substances, and the marihuana and cocaine were seized. The defendant moved to suppress the narcotics.
The motion judge found that:
“The Troopers testified that they stopped at the rest area and approached the [vehicle] the second time for a ‘well being’ check. They asked the Defendant to get out of the vehicle for possible medical problems and in the back of their minds was the thought that the Defendant might have been on a narcotics bender and thought the fresh air might do him good.
“I find that they in fact had a hunch that the Defendant had used narcotics and that they would find evidence when he exited the vehicle.”
The motion judge went on to conclude that our decision in *762Commonwealth v. Leonard, 422 Mass. 504, cert. denied, 519 U.S. 877 (1996), “[p]erhaps ... in this case justifies the troopers’ initial approach of the vehicle and having conversation with the Defendant on the grounds that he might have been ill or in some other kind of difficulty, but I am of the opinion that the troopers went too far at the time the Defendant was told to get out of the car so that his rights were violated at this time .... There was no evidence produced that the troopers even inquired as to the Defendant’s health or the need for aid at this time. The troopers had a hunch that he was under the influence of a narcotic and had him exit the car. At this point they went beyond the caretaking function and were looking for evidence of a narcotics violation.”
The Appeals Court reversed. 44 Mass. App. Ct. 736 (1998). In its recital of the facts, the court stated that the officers asked the defendant to get out of the vehicle because they were “[cjoncerned about his condition .... They did so . . . because they ‘thought that the defendant might have been on a narcotics bender and fresh air might do him good.’ ” Id. at 738. Applying our decision in the Leonard case and the Supreme Court’s decision in Cady v. Dombrowski, 413 U.S. 433 (1973), the Appeals Court held that the officers, as part of their “community caretaking functions,” id., quoting Cady v. Dombrowski, supra at 441, had acted reasonably. “Accepting the judge’s findings regarding the defendant’s condition, the troopers had an objective basis for believing that the defendant’s safety and well-being were in jeopardy.” Commonwealth v. Murdough, supra at 739. The Appeals Court concluded that, because the officers’ actions were reasonable in light of this objective basis, those actions violated neither the Fourth Amendment to the United States Constitution nor art. 14 of the Massachusetts Declaration of Rights, which in this respect are coextensive. Id. at 740 & n.6. Citing the recent decision of the Supreme Court in Whren v. United States, 517 U.S. 806, 812 (1996), the Appeals Court added that “an officer’s motive [does not] invalidate[] objectively justifiable behavior.” Id. at 740.
n
The Appeals Court’s analysis is correct.
The defendant complains that the Appeals Court substituted its own view of the facts for those of the motion judge, who heard the testimony and saw the witnesses. While the defendant *763is quite right that the findings of the motion judge are owed deference on appeal, Commonwealth v. Murphy, 362 Mass. 542, 547 (1972), the Appeals Court did not violate that principle here. First, an appellate court can have no obligation to defer to a judge’s finding that is incorrect on its face. The motion judge stated in his findings that “[tjhere was no evidence produced that the troopers even inquired as to the Defendant’s health or the need for aid at this time.” But the record plainly contradicts that statement. One of the officers testified that he asked the defendant “if he was okay,” and the other officer testified that they first had asked the defendant “if he was on any type of medication or narcotics.” Moreover, one of the officers also testified that at the time they asked the defendant to step out of the vehicle, they were concerned “that he had some type of medical condition.”1 The judge need not have believed this testimony, but he was incorrect to state that no such evidence had been produced.
But even on the facts as found, the motion to suppress should not have been granted. The judge’s analysis was mistaken. First, he assumed that the officers were required to have some reasonable basis for their initial approach and inquiry, but it is quite clear that officers may make inquiry of anyone they wish and knock on any door, so long as they do not implicitly or explicitly assert that the person inquired of is not free to ignore their inquiries. See Florida v. Bostick, 501 U.S. 429, 434 (1991); Florida v. Royer, 460 U.S. 491, 497 (1983); Terry v. Ohio, 392 U.S. 1, 16 (1968) (“whenever a police officer accosts an individual and restrains his freedom to walk away, he has ‘seized’ that person”). Cf. Schneckloth v. Bustamonte, 412 U.S. 218, 227 (1973) (consent search valid in absence of probable cause). Officers may not engage in an investigatory stop or brief detention except on reasonable suspicion. See Terry v. Ohio, supra. There must be probable cause to arrest. But it would introduce an altogether new and disastrous complication to require some preliminary showing of need or reasonableness to justify an entirely noncoercive inquiry. And if the police, in pursuing their inquiries, may knock on any door, they may also knock on any vehicle window without having to explain why, should that initial, noncoercive inquiry ripen into something *764more, as it did here. Thus, it was clear in the Leonard case that the officer’s initial approach to the parked vehicle and the officer’s knocking on the window raised no constitutional issue at all. It was only when the officer opened Leonard’s door that a justification for that action had to be offered. In contrast, in Commonwealth v. Smigliano, 427 Mass. 490, 491-492 (1998), the officer’s approach required justification because he had first activated his blue lights, which clearly indicated to the driver of the parked vehicle that he was not free to go.2 The point at which a constitutional question first arose in this case was when the defendant was told to get out of his vehicle.
The judge noted, and the record reflects, that the officers suspected that the defendant was under the influence of narcotics. It is not a crime to be under the influence of narcotics, although certainly it is a crime to operate a motor vehicle while under such influence. And operation of a vehicle when in a narcotic stupor presents a danger to the driver and to the public. If the community caretaking function, to which both the judge and the Appeals Court refer, means anything, surely it allows a police officer to determine whether a driver is in such a condition that if he resumes operation of the vehicle, in which he is seated at a highway rest stop, he will pose such an extreme danger to himself and others. The officers testified that they asked the defendant to step out of the vehicle to be able further to observe his condition and because they thought that the cold air would sober him up. The judge suppressed the evidence that came into plain view as the defendant stepped out of the vehicle because he concluded “they went beyond the caretaking function and were looking for evidence of a narcotics violation.” Nothing better illustrates the good sense of the Whren rule. If the judge had believed the officers’ stated reasons, then their action could only be viewed as eminently reasonable. But the judge did not believe the officers’ stated reasons. Or, rather, he thought that they had an ulterior motive as well, because in his *765findings he also concluded that “[t]hey asked the Defendant to get out of the vehicle for possible medical problems and in the back of their minds was the thought that the Defendant might have been on a narcotics bender and thought the fresh air might do him good.” The judge did see and hear the witnesses; we have only the record. But there is nothing at all in that record to suggest that the police officers were not acting for precisely the reason stated — except a generalized, free-floating suspicion. Whren v. United States, 517 U.S. 806 (1996), teaches that, if the objective circumstances justify the action taken, that is enough. That is the sounder rule and certainly invites less unan-chored guesswork on the part of a motion judge.
The order allowing the motion to suppress is reversed.
So ordered.
The defendant testified that before the officer asked him to step out of the vehicle, he asked whether the defendant was “an IV drug user” and why the defendant was shivering. He did not recall being asked any other questions.
If the defendant had continued to ignore the officers’ inquiry or had refused to produce a license and registration and the officers had chosen to take this recalcitrance as a justification for more intrusive action, a different set of questions would arise. Such recalcitrance alone may not, but together with other circumstances may, justify a brief investigatory detention. See, e.g., Commonwealth v. Silva, 366 Mass. 402, 406-407 (1974); Commonwealth v. Torres, 40 Mass. App. Ct. 6, 9 (1996). Also, G. L. c. 90, § 25, provides a penalty for the refusal of a person in control of a motor vehicle to produce his driver’s license to a police officer on the officer’s request.