The defendant, Thomas J. Shields, was stopped at a State police “sobriety checkpoint” (roadblock) at *163approximately 1:15 a.m. on September 13, 1986. After performing several field sobriety tests, Shields was arrested and charged with operating his vehicle while under the influence of intoxicating liquor in violation of G. L. c. 90, § 24 (1986 ed.).

Shields moved to suppress the evidence obtained following his stop at the roadblock, contending that it was the fruit of an unlawful seizure. In support of this motion, Shields argued that the Commonwealth must prove that no less intrusive alternative would be as effective as roadblocks in enforcing c. 90, § 24, before the roadblock seizure could be found to be constitutionally permissible and the evidence obtained at the roadblock admitted. The Commonwealth acknowledged that it must prove that the roadblock was conducted in accordance with the procedures outlined in Commonwealth v. Trumble, 396 Mass. 81 (1985), and Commonwealth v. McGeoghegan, 389 Mass. 137 (1983), but denied that it must disprove the existence of equally effective yet less intrusive alternatives to enforcing c. 90, § 24, before the evidence obtained at the roadblock could be admit-

The judge noted that resolution of the dispute was likely to be dispositive of Shields’s case, that the issue was likely to arise in similar proceedings, and that an improper determination in the trial court that the Commonwealth must disprove the existence of equally effective, less intrusive alternatives to roadblocks would result in unnecessary expenditure of judicial resources at trial. Accordingly, the judge properly reported the following two questions to the Appeals Court under Mass. R. Crim. P. 34, 378 Mass. 905 (1979): “1. Whether, as a precondition to the admission of evidence obtained as a result of a sobriety checkpoint or roadblock operated by law enforcement personnel, the Commonwealth is required to prove that there was no less intrusive alternative to the checkpoint or roadblock which would have been effective to accomplish the legitimate public safety goals of the Commonwealth. 2. Whether, assuming that the preceding question is answered in the affirmative, the standard of proof by which the Commonwealth must bear its burden is beyond reasonable doubt, by clear and convincing *164evidence or by a preponderance of the evidence.” We granted the parties’ application for direct appellate review of these questions.

The defendant grounds his argument in both the Fourth Amendment to the Constitution of the United States and art. 14 of the Declaration of Rights of the Massachusetts Constitution.1 We conclude that neither of these provisions requires the Commonwealth to prove that there are no equally effective yet less intrusive alternatives for enforcing G. L. c. 90, § 24, than roadblocks. We therefore answer question one in the negative, and need not address question two.

The stop of Shields’s motor vehicle was a seizure. Commonwealth v. Trumble, supra at 86. This seizure violates the Fourth Amendment and art. 14 only if it was unreasonable. See, e.g., INS v. Delgado, 466 U.S. 210, 215 (1984); Commonwealth v. Sheppard, 394 Mass. 381, 391 (1985). Decisions of this court and of the Supreme Court establish that there is “no ready test for determining reasonableness other than by balancing the need to search [or seize] against the invasion which the search [or seizure] entails.” Commonwealth v. Silva, 366 Mass. 402, 405 (1974), quoting Camara v. Municipal Court of the City of San Francisco., 387 U.S. 523, 536-537 (1967) (administrative search). See Trumble, supra at 86 (to determine reasonableness of seizure court balances “the public interest against ‘the individual’s right to personal security free from arbitrary interference by law officers’ ”), quoting United States v. Brignoni-Ponce, 422 U.S. 873, 878 (1975).

Because Shields was seized without a warrant, the Commonwealth bears the burden of proving that the seizure was reasonable. Commonwealth v. Antobenedetto, 366 Mass. 51, 57 (1974). To carry its burden of proving that the roadblock seizure was reasonable the Commonwealth must show, at least, that the roadblock was conducted in accordance with the guidelines established in Trumble, supra, and Commonwealth v. Mc-*165Geoghegan, 389 Mass. 137 (1983). See Commonwealth v. Amaral, 398 Mass. 98, 101 (1986). Adherence to these guidelines, the content of which need not be recited here, assures that a roadblock seizure is the result of a “plan embodying explicit, neutral limitations on the conduct of individual officers. ”Brown v. Texas, 443 U.S. 47, 51 (1979). Conducting roadblocks in accordance with such neutral criteria minimizes the risk “that the individual’s reasonable expectation of privacy [will be] ‘subject to the discretion of the official in the field. ’ ” Delaware v. Prouse, 440 U.S. 648, 655 (1979), quoting Camara, supra at 532. Adherence to the guidelines’ requirements also assures that the surprise, fear, and inconvenience to — and therefore the intrusion on — the motoring public is minimized. See McGeoghegan, supra at 143-144. In sum, leaving aside the question of less intrusive alternatives, where the Commonwealth shows that a roadblock employed to enforce c. 90, § 24, was operated in accordance with the established guidelines, the accompanying seizures, although not conducted on the basis of individualized suspicion, are reasonable under the Fourth Amendment and art. 14. Trumble, supra at 89-90.2

Shields, of course, does not leave aside the question of less intrusive alternatives. He argues that, in order for the Commonwealth to meet its burden of showing that the roadblock seizure at issue here was reasonable, it must prove that there was no *166equally effective yet less intrusive alternative to enforcing c. 90, § 24. We disagree.

Less intrusive alternative analysis traditionally has not been employed in determining the constitutional reasonableness of searches and seizures. Indeed, in one case involving a vehicle search we declined to employ less intrusive alternative analysis and observed that “[t]he fact that, in the abstract, less intrusive means might have been used does not, by itself, render the search unreasonable.” Commonwealth v. Ortiz, 376 Mass. 349, 357 (1978), citing Cady v. Dombrowski, 413 U.S. 433, 447 (1973). Accord United States v. Sharpe, 470 U.S. 675, 687 (1985) (“The question is not simply whether some other alternative was available, but whether the police acted unreasonably in failing to recognize or to pursue it”); United States v. Villamonte-Marquez, 462 U.S. 579, 591 n.5 (1983); United States v. Martinez-Fuerte, 428 U.S. 543, 556 n.12 (1976). The defendant does not address the language quoted from Ortiz, supra, nor does he indicate why the principle of that language is inapplicable in this case.

Article 14 and the Fourth Amendment proscribe only unreasonable law enforcement conduct. As such, these provisions evince a policy of accommodating the legitimate State interest in law enforcement while preventing arbitrary searches and seizures. It would be inconsistent with that policy to rule that, in order to prove that a search or seizure is lawful, the Commonwealth must prove that each of a multiplicity of proffered hypothetical courses of conduct if used would be either less effective or more intrusive. Where the defendant merely conjectures that equally effective yet less intrusive means of enforcing c. 90, § 24, exist, “[t]he [Commonwealth] is entitled in the interest of public safety to bring all available resources to bear, without having to spell out the exact efficiency coefficient of each component and of the separate effects of any particular component.” People v. Scott, 63 N.Y.2d 518, 528-529 (1984). The focus of the inquiry is on the conduct which in fact occurred. The Commonwealth’s burden is to prove that the intrusion generated by that conduct is outweighed by the need to search or seize. Commonwealth v. Silva, supra at 405.

*167We reject the defendant’s argument that the result we reach opens the door for suspicionless searches and seizures in other contexts. Police will not be allowed, for example, to cordon off “high crime areas” and search all the people on the street. Intrusions of this level, even for a limited search, require some degree of articulable individualized suspicion. Terry v. Ohio, 392 U.S. 1 (1968). Roadblock seizures for enforcing c. 90, § 24, are virtually sui generis in this regard.3 Their constitutionality is based in large measure on the lower expectation of privacy traditionally accorded to the motoring public. See, e.g., Commonwealth v. Ortiz, supra at 357-358 & n.7, and cases cited; People v. Scott, supra at 525. We do not view our decision today as eroding the protection against unreasonable searches and seizures afforded by art. 14 and the Fourth Amendment.

Rather than eroding the constitutional protection against unreasonable search and seizure, our decision is consistent with precedent. Roadblock seizures have been upheld in the absence of individualized suspicion and without a showing of no equally effective yet less intrusive alternative. United States v. Martinez-Fuerte, supra at 545, 556-557 & n.12 (1976) (permanent roadblock conducted sixty-six miles from border to detect illegal aliens; less intrusive alternative analysis rejected). See Delaware v. Prouse, supra at 663 (indicating that roadblock stops of all oncoming traffic are permissible). In the analogous context of courthouse entry searches we have approved an initial search not based on articulable individualized suspicion so long as it “was no more intrusive than necessary.” Commonwealth v. Harris, 383 Mass. 655, 657 (1981). In the case of roadblocks to enforce c. 90, § 24, compliance with the Trumble and McGeoghegan guidelines assures that the initial seizure is *168no more intrusive than necessary. We perceive nothing in the prior decisions, nor anything in the nature of art. 14 or the Fourth Amendment, which requires the Commonwealth to disprove the existence of equally effective yet less intrusive alternatives to enforcing c. 90, § 24.

Although there is some support elsewhere for the defendant’s position, the result we reach appears to be consistent with the weight of authority from other jurisdictions. Some courts which have addressed the constitutionality of roadblocks to prevent intoxicated driving have required a showing of no less intrusive yet equally effective alternatives. State v. Superior Court, 143 Ariz. 45, 48-49 (1984) (State sustaining its burden). State v. Koppel, 127 N.H. 286, 292 (1985) (State constitutional grounds). Higbie v. State, 723 S.W.2d 802, 805 (Tex. Crim. App. 1987). See State v. Muzik, 379 N.W.2d 599, 604 (Minn. Ct. App. 1985) (State must demonstrate either need for roadblock or its superiority to less intrusive alternatives). The majority of jurisdictions discussing the existence of other alternatives, however, either have rejected this requirement, People v. Bartley, 109 Ill. 2d 273, 287 (1985), cert. denied, 475 U.S. 1068 (1986), rev’g 125 Ill. App. 3d 575, 578 (1984), which had required a showing of no less intrusive yet equally effective alternative; State v. Garcia, 500 N.E.2d 158, 162-163 (Ind. 1986), cert. denied, 481 U.S. 1014 (1987), overruling State v. McLaughlin, 471 N.E.2d 1125 (Ind. Ct. App. 1984), which had required a showing of no less intrusive yet equally effective alternative; Little v. State, 300 Md. 485, 504-506 (1984); People v. Scott, supra at 528-529, or have indicated that the presence of such alternatives is merely one factor to be considered in determining the constitutional reasonableness of the roadblock seizures. State v. Jones, 483 So. 2d 433, 437-438 (Fla. 1986). State v. Deskins, 234 Kan. 529, 541 (1983).

Question one is answered in the negative. Question two therefore need not be reached. This case is remanded for proceedings consistent with this opinion.

(dissenting, with whom Lynch, J., joins). A review of the various decisions of the United States Supreme Court and of this court, dealing with the constitutionality of automobile roadblocks, reveals how the United States Supreme Court and, sadly, this court have slipped away from basic constitutional principles. Additionally, both the Federal decisions and our decisions offer an almost classic illustration of dictum building on dictum to become a rule of law. I write separately, in dissent, because I hope to refocus this debate on the fundamental principles of the jurisprudence of search and seizure law under both Federal and State Constitutions.

The fundamental principle under both the Fourth Amendment to the United States Constitution and art. 14 of the Massachusetts Declaration of Rights has been that no search or seizure is to be deemed “reasonable” unless based on a warrant issued on probable cause.1 This rule, like any other rule of law, has its exceptions, but it is basic. Yet, the court cavalierly brushes this rule aside by stating erroneously that: “The basic issue is the reasonableness of the search, not the presence or absence of probable cause to believe evidence of a crime is likely to be found.” Ante at 165 n.2. We are told that the test of a reasonable search or seizure is that of balancing the need to search or seize against the invasion of privacy which the search or seizure entails. It is true in this case, as well as in the companion case, Commonwealth v. Lovelace, post 1002 (1988), *170decided this day,2 that the parties also do not address this fundamental issue. It is true that this court did not come squarely to grips with this question in Commonwealth v. McGeoghegan, 389 Mass. 137 (1983), or in Commonwealth v. Trumble, 396 Mass. 81 (1985), or in Commonwealth v. Amaral, 398 Mass. 98 (1986).

Additionally, I do not believe that the court has faced up to the potential differences of result as matter of State constitutional law, but rather has followed the vacillating lead of the United States Supreme Court.3 See, e.g., McGeoghegan, supra at 141 n.2 (same factors are material under Federal and State Constitutions; no discussion); Trumble, supra at 89-90 (seizure pursuant to McGeoghegan guidelines would be reasonable under State and Federal Constitutions; no discussion); id. at 96 n.3 (Abrams, J., concurring) (no separate argument made by defendants); Amaral, supra at 101 (roadblock invalid under art. 14 and probably so under Fourth Amendment for failure to meet McGeoghegan guidelines; no discussion of differences between State and Federal law — or of probable cause or the warrant requirements).

Let us start with a look at McGeoghegan in an effort to illustrate where we have gone astray. In that case we ruled that stopping a vehicle in a police roadblock “was a seizure within the meaning of the Fourth and Fourteenth Amendments.” McGeoghegan, supra at 139. We also recognized that “[t]he reasonableness standard usually requires that the facts on which an intrusion is based be measured against probable cause, Carroll v. United States, 267 U.S. 132, 149 (1925), or, in limited instances, on articulable, reasonable suspicion focusing on the affected individual. United States v. Brignoni-Ponce, [422 U.S. 873, 881 (1975)].” Id. We acknowledged also the holding of Delaware v. Prouse, 440 U.S. 648 (1979), *171that random stops for license and registration checks could not be justified absent “at least articulable and reasonable suspicion.” Id. at 663.4 We then went forward, in dictum, to build on the dictum in Delaware v. Prouse,5 and set forth guidelines of reasonableness as to roadblocks.6

The dictum of McGeoghegan, built on the dictum of Delaware v. Prouse, seems to have become the rule shortly thereafter in Commonwealth v. Trumble, supra.7 The court stated *172in Trumble, supra at 86: “It is well established that the stopping of each defendant’s motor vehicle was a seizure within the Fourth and Fourteenth Amendments to the United States Constitution. Delaware v. Prouse, 440 U.S. 648, 653-654 (1979). Our inquiry becomes, therefore, whether the seizures were reasonable. McGeoghegan, supra at 139. Accordingly, we must balance the public interest against ‘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).” (Emphasis supplied.) Thus, “balancing,” not probable cause, reasonable and articulable suspicion, or the presence or absence of a warrant, became the test.8 The court today falls into the same error when it states, ante at 164: “Decisions of this court and of the Supreme Court establish that there is ‘no ready test for determining reasonableness other than by balancing the need to search [or seize] against the invasion which the search [or seizure] entails.’ Commonwealth v. Silva, 366 *173Mass. 402, 405 (1974), quoting Camara v. Municipal Court of the City of San Francisco, 387 U.S. 523, 536-537 (1967) (administrative search). See Trumble, supra [at 86] (to determine reasonableness of seizure court balances ‘the public interest against “the individual’s right to personal security free from arbitrary interference by law officers,”)’ quoting United States v. Brignoni-Ponce, 422 U.S. 873, 878 (1975).”9

I have pointed out already the flaw in the Trumble reasoning. I add just a brief comment as to Commonwealth v. Silva, supra, which the court cites for support today. Silva was not a roadblock case but a stop and frisk case involving a disabled passenger vehicle. The ensuing search of the vehicle was held unlawful as being excessive, even though the initial stop was lawful. The “balancing” done in Silva was not as to the initiation of the stop (seizure), but as to the extent of the intrusion. Silva clearly adheres to the requirement of individualized suspicion and does not support the court’s sweeping assertions in Trumble, or in the present case.

The court refers also to Commonwealth v. Ortiz, 376 Mass. 349 (1978), as further support for its position. In Commonwealth v. Ortiz, supra at 353, however, we stated: “The Commonwealth bears the burden of showing the existence of both probable cause to believe the car contained contraband and exigent circumstances to justify the seizure without a search warrant. See Commonwealth v. Antobenedetto, 366 Mass. 51, 57 (1974).”10

*174To justify further its position, the court has referred in Trumble, and in this opinion, to the “strong public interest” (Trumble, supra at 86), in reducing the harm done by drunken drivers. The results the court reaches today are described as “sui generis,” limited to this large social need, based also, in part, on the “lower expectations of privacy” accorded the motoring public. The approach taken here, we are assured, cannot be extended to “high crime areas.” One must assume then that (under the Federal case law) only detection of aliens at fixed border roadblocks, see United States v. Martinez-Fuerte, 428 U.S. 543 (1976), and (under State law) apprehension of drunken drivers raise the level of public interest to the point where we shall put aside traditional rules and balance, instead, public interest against privacy interests. Does this mean that drug dealing and illegal possession of deadly weapons are lesser concerns? Or does it means that pedestrians are safe, but drivers and passengers are fair game? More likely, it means that “sui generis,” however well meant, is an illusory promise.

Automobiles are not beyond the Fourth Amendment’s protection. Consider these words in Almeida-Sanchez v. United States, 413 U.S. 266, 269 (1973), referring to the exception to the warrant requirement as to automobiles created by Carroll v. United States, 267 U.S. 132 (1925): “The Carroll doctrine does not declare a field day for the police in searching automobiles. Automobile or no automobile, there must be probable cause for the search.”

The public’s interest in barring the entry of illegal aliens and those interests involving enforcement of liquor laws, including the apprehension of drunken drivers, are not necessarily the same. The Court, in Almeida-Sanchez, supra at 274-275, recognized this when it quoted Chief Justice Taft in Carroll as follows: “ ‘It would be intolerable and unreasonable if a prohibition agent were authorized to stop every automobile on *175the chance of finding liquor and thus subject all persons lawfully using the highways to the inconvenience and indignity of such a search. Travellers may be so stopped in crossing an international boundary because of national self protection reasonably requiring one entering the country to identify himself as entitled to come in, and his belongings as effects which may be lawfully brought in. But those lawfully within the country, entitled to use the public highways, have a right to free passage without interruption or search unless there is known to a competent official authorized to search, probable cause for believing that their vehicles are carrying contraband or illegal merchandise. ’ 267 U.S., at 153-154.”

In United States v. Ortiz, 422 U.S. 891, 896-897 (1975), the Court invalidated a border checkpoint seizure and said: “A search, even of an automobile, is a substantial invasion of privacy. To protect that privacy from official arbitrariness, the Court always has regarded probable cause as the minumum requirement for a lawful search. Almeida-Sanchez, 413 U.S. at 269-270; Chambers v. Maroney, 399 U.S. 42, 51 (1970). We are not persuaded that the differences between roving patrois and traffic checkpoints justify dispensing in this case with the safeguards we required in Almeida-Sanchez. We therefore follow that decision and hold that at traffic checkpoints removed from the border and its functional equivalents, officers may not search private vehicles without consent or probable cause.”

Unfortunately, all of its own strictures were abandoned by the Court in United States v. Martinez-Fuerte, 428 U.S. 543 (1976). There the Court, for the first time, upheld border checkpoint stops on the basis of the “substantiality of the public interest” and the impracticality of requiring reasonable suspicion as the basis of the stop. Id. at 556. Justice Brennan’s statement in dissent should be our guide: “Consistent with this purpose to debilitate Fourth Amendment protections, the Court’s decision today virtually empties the Amendment of its reasonableness requirement by holding that law enforcement officials manning fixed checkpoint stations who make standard-less seizures of persons do not violate the Amendment. This holding cannot be squared with this Court’s recent decisions *176in United States v. Ortiz, [supra]; United States v. Brignoni-Ponce, 422 U.S. 873 (1975); and Almeida-Sanchez v. United States, [supra]. I dissent.” United States v. Martinez-Fuerte, supra at 568-569 (Brennan, J., dissenting).

More recently, when this “sui generis” concept was extended to drug searches of boats on interior waterways, Justice Brennan commented in United States v. Villamonte-Marquez, 462 U.S. 579, 610 (1983) (Brennan, J., dissenting):11 “In dissent in Martinez-Fuerte, I expressed my fear that the Court’s decision was part of a ‘continuing evisceration of Fourth Amendment protections against unreasonable searches and seizures.’ 428 U.S. at 567. The majority chided me for my rhetoric and my ‘unwarranted concern,’ pointing out that its holding was expressly and narrowly limited: ‘Our holding today, approving routine stops for brief questioning . . . is confined to permanent checkpoints. ’ Id. at 566 n.19. Today the Court breaks that promise. I dissent.”12

In my view, the same lapses are infecting this court with a foreseeable expansion of the doctrine reiterated today. We have not hesitated to grant to our citizens greater protection under art. 14,13 and we should do so here. In Trumble, Justice *177Lynch concluded his dissent (in which I joined), by asking the court to justify its departure from its “traditional concern” for privacy rights. He stated:

“The court’s holding that the seizures at the Sunderland roadblocks were reasonable contrasts shaiply with other decisions of this court concerning the scope of protection afforded by the Fourth Amendment. See, e.g., Commonwealth v. Pietrass, 392 Mass. 892, 898-900 (1984) (even though there was probable cause to arrest the defendant on charges of aggravated rape and other violent crimes, the Commonwealth failed to meet its burden of showing exigency, so the police were not justified in making a warrantless entry of a dwelling to arrest him); Commonwealth v. Thibeau, 384 Mass. 762, 763-764 (1981) (even though defendant was riding a bicycle, a known means of transporting illegal drugs, and made a sudden left turn as police cruiser approached, police lacked probable cause to arrest him and seize envelopes containing narcotics that were sticking out of his pocket); Commonwealth v. Bacon, 381 Mass. 642, 645-646 (1980) (police were not justified in making investigatory stop of relatively expensive motor vehicle operated by two youthful appearing men, even though one attempted to conceal his face, presumably from police view). I am unable to reconcile the court’s ruling that the Commonwealth has sustained its burden in this case with the traditional concern this court has expressed for protecting Fourth Amendment rights. Here, the court concludes that the warrantless stop of 503 vehicles was justified even though the police lacked a basis for suspecting that any particular operator was or *178had been engaged in criminal activity. The court gives no satisfactory explanation for why it has suddenly lowered the threshold showing which the Commonwealth has traditionally been required to make to justify a warrantless stop or arrest.” Commonwealth v. Trumble, 396 Mass. 81, 101-102 (1985).

Today’s decision again fails to give a “satisfactory explanation” for “lowering] the threshold. ” Accordingly, I dissent.14