opinion: PENNSYLVANIA v. MIMMS
  No. 76-1830.
  Decided December 5, 1977
  Per Curiam.
  Petitioner Commonwealth seeks review of a judgment of the Supreme Court of Pennsylvania reversing respondent’s conviction for carrying a concealed deadly weapon and a firearm without a license. That court reversed the conviction because it held that respondent’s “revolver was seized in a manner which violated the Fourth Amendment to the Constitution of the United States.” 471 Pa. 546, 548, 370 A. 2d 1157, 1158 (1977). Because we disagree with this conclusion, we grant the Commonwealth’s petition for certiorari and reverse the judgment of the Supreme Court of Pennsylvania.
  The facts are not in dispute. While on routine patrol, two Philadelphia police officers observed respondent Harry Mimms driving an automobile with an expired license plate. The officers stopped the vehicle for the purpose of issuing a traffic summons. One of the officers approached and asked respondent to step out of the car and produce his owner’s card and operator’s license. Respondent alighted, whereupon the officer noticed a large bulge under respondent’s sports jacket. Fearing that the bulge might be a weapon, the officer frisked respondent and discovered in his waistband a .38-caliber revolver loaded with five rounds of ammunition. The other occupant of the car was carrying a .32-caliber revolver. Respondent was immediately arrested and subsequently indicted for carrying a concealed deadly weapon and for unlawfully carrying a firearm without a license. His motion to suppress the revolver was denied; and, after a trial at which the revolver was introduced into evidence, respondent was convicted on both counts.
  As previously indicated, the Supreme Court of Pennsylvania reversed respondent’s conviction, however, holding that the revolver should have been suppressed because it was seized contrary to the guarantees contained in the Fourth and Fourteenth Amendments to the United States Constitution. The Pennsylvania court did not doubt that the officers acted reasonably in stopping the car. It was also willing to assume, arguendo, that the limited search for weapons was proper once the officer observed the bulge under respondent’s coat. But the court nonetheless thought the search constitutionally infirm because the officer's order to respondent to get out of the car was an impermissible “seizure.” This was so because the officer could not point to “objective observable facts to support a suspicion that criminal activity was afoot or that the occupants of the vehicle posed a threat to police safety.” Since this unconstitutional intrusion led directly to observance of the bulge and to the subsequent “pat down,” the revolver was the fruit of an unconstitutional search, and, in the view of the Supreme Court of Pennsylvania, should have been suppressed.
  We do not agree with this conclusion. The touchstone of our analysis under the Fourth Amendment is always “the reasonableness in all the circumstances of the particular governmental invasion of a citizen’s personal security.” Terry v. Ohio, 392 U. S. 1, 19 (1968). Reasonableness, of course, depends “on a balance between the public interest and the individual’s right to personal security free from arbitrary interference by law officers.” United States v. Brignoni-Ponce, 422 U. S. 873, 878 (1975).
  In this case, unlike Terry v. Ohio, there is no question about the propriety of the initial restrictions on respondent’s freedom of movement. Respondent was driving an automobile with expired license tags in violation of the Pennsylvania Motor Vehicle Code. Deferring for a moment the legality of the “frisk” once the bulge had been observed, we need presently deal only with the narrow question of whether the order to get out of the car, issued after the driver was lawfully detained, was reasonable and thus permissible under the Fourth Amendment. This inquiry must therefore focus not on the intrusion resulting from the request to stop the vehicle or from the later “pat down,” but on the incremental intrusion resulting from the request to get out of the car once the vehicle was lawfully stopped.
  Placing the question in this narrowed frame, we look first to that side of the balance which bears the officer’s interest in taking the action that he did. The State freely concedes the officer had no reason to suspect foul play from the particular driver at the time of the stop, there having been nothing unusual or suspicious about his behavior. It was apparently his practice to order all drivers out of their vehicles as a matter of course whenever they had been stopped for a traffic violation. The State argues that this practice was adopted as a precautionary measure to afford a degree of protection to the officer and that it may be justified on that ground. Establishing a face-to-face confrontation diminishes the possibility, otherwise substantial, that the driver can make unobserved movements; this, in turn, reduces the likelihood that the officer will be the victim of an assault.
  We think it too plain for argument that the State’s proffered justification — the safety of the officer — is both legitimate and weighty. “Certainly it would be unreasonable to require that police officers take unnecessary risks in the performance of their duties.” Terry v. Ohio, supra, at 23. And we have specifically recognized the inordinate risk confronting an officer as he approaches a person seated in an automobile. “According to one study, approximately 30% of police shootings occurred when a police officer approached a suspect seated in an automobile. Bristow, Police Officer Shootings — A Tactical Evaluation, 54 J. Crim. L. C. & P. S. 93 (1963).” Adams v. Williams, 407 U. S. 143, 148 n. 3 (1972). We are aware that not all these assaults occur when issuing traffic summons, but we have before expressly declined to accept the argument that traffic violations necessarily involve less danger to officers than other types of confrontations. United States v. Robinson, 414 U. S. 218, 234 (1973). Indeed, it appears “that a significant percentage of murders of police officers occurs when the officers are making traffic stops.” Id., at 234 n. 5.
  The hazard of accidental injury from passing traffic to an officer standing on the driver’s side of the vehicle may also be appreciable in some situations. Rather than conversing while standing exposed to moving traffic, the officer prudently may prefer to ask the driver of the vehicle to step out of the car and off onto the shoulder of the road where the inquiry may be pursued with greater safety to both.
  Against this important interest we are asked to weigh the intrusion into the driver’s personal liberty occasioned not by the initial stop of the vehicle, which was admittedly justified, but by the order to get out of the car. We think this additional intrusion can only be described as de minimis. The driver is being asked to expose to view very little more of his person than is already exposed. The police have already lawfully decided that the driver shall be briefly detained; the only question is whether he shall spend that period sitting in the driver’s seat of his car or standing alongside it. Not only is the insistence of the police on the latter choice not a “serious intrusion upon the sanctity of the person,” but it hardly rises to the level of a “ ‘petty indignity.’ ” Terry v. Ohio, supra, at 17. What is at most a mere inconvenience cannot prevail when balanced against legitimate concerns for the officer’s safety.
  There remains the second question of the propriety of the search once the bulge in the jacket was observed. We have as little doubt on this point as on the first; the answer is controlled by Terry v. Ohio, supra. In that case we thought the officer justified in conducting a limited search for weapons once he had reasonably concluded that the person whom he had legitimately stopped might be armed and presently dangerous. Under the standard enunciated in that case— whether “the facts available to the officer at the moment of the seizure or the search ‘warrant a man of reasonable caution in the belief’ that the action taken was appropriate” — there is little question the officer was justified. The bulge in the jacket permitted the officer to conclude that Mimms was armed and thus posed a serious and present danger to the safety of the officer. In these circumstances, any man of “reasonable caution” would likely have conducted the “pat down.”
  Respondent’s motion to proceed in forma pauperis is granted. The petition for writ of certiorari is granted, the judgment of the Supreme Court of Pennsylvania is reversed, and the case is remanded for further proceedings not inconsistent with this opinion.
  It is so ordered.
  Three judges dissented on the federal constitutional issue.
  471 Pa., at 552, 370 A. 2d, at 1160.
  We note that in his brief in opposition to a grant of certiorari respondent contends that this case is moot because he has already completed the 3-year maximum of the 1%- to 3-year sentence imposed. The case has, he argues, terminated against him for all purposes and for all time regardless of this Court’s disposition of the matter. See St. Pierre v. United States, 319 U. S. 41 (1943).
  But cases such as Sibron v. New York, 392 U. S. 40, 53-57 (1968); Street v. New York, 394 U. S. 576 (1969); Carafas v. LaVallee, 391 U. S. 234 (1968); and Ginsberg v. New York, 390 U. S. 629 (1968), bear witness to the fact that this Court has long since departed from the rule announced in St. Pierre, supra. These more recent cases have held that the possibility of a criminal defendant’s suffering “collateral legal consequences” from a sentence already served permits him to have his claims reviewed here on the merits. If the prospect of the State’s visiting such collateral consequences on a criminal defendant who has served his sentence is a sufficient burden as to enable him to seek reversal of a decision affirming his conviction, the prospect of the State’s inability to impose such a burden following a reversal of the conviction of a criminal defendant in its own courts must likewise be sufficient to enable the State to obtain review of its claims on the merits here. In any future state criminal proceedings against respondent, this conviction may be relevant to setting bail and length of sentence, and to the availability of probation. 18 Pa. Cons. Stat. Ann. §§ 1321, 1322, 1331, 1332 (Purdon Supp. 1977); Pa. Rule Crim. Proc. 4004. In view of the fact that respondent, having fully served his state sentence, is presently incarcerated in the federal penitentiary at Lewisburg, Pa., we cannot say that such considerations are unduly speculative even if a determination of mootness depended on a case-by-case analysis.
  Operating an improperly licensed motor vehicle was at the time of the incident covered by 1959 Pa. Laws, No. 32, which was found in Pa. Stat. Ann., Tit. 75, §511 (a) (Purdon 1971), and has been repealed by 1976 Pa. Laws, No. 81, § 7, effective July 1, 1977. This offense now appears to be covered by 75 Pa. Cons. Stat. Ann. §§ 1301, 1302 (Purdon 1977).
  The State does not, and need not, go so far as to suggest that an officer may frisk the occupants of any car stopped for a traffic violation. Rather, it only argues that it is permissible to order the driver out of the car. In this particular case, argues the State, once the driver alighted, the officer had independent reason to suspect criminal activity and present danger and it was upon this basis, and not the mere fact that respondent had committed a traffic violation, that he conducted the search.
  Contrary to the suggestion in the dissent of our Brother Stevens, post, at 122, we do not hold today that “whenever an officer has an occasion to speak with the driver of a vehicle, he may also order the driver out of the car.” We hold only that once a motor vehicle has been lawfully detained for a traffic violation, the police officers may order the driver to get out of the vehicle without violating the Fourth Amendment’s proscription of unreasonable searches and seizures.
  392 U. S., at 21-22.