LAW RESEARCH

Briefs of Counsel, p 921, infra.

p.660

substantially similar to the Fourth Amendment, since the Delaware Supreme Court had not rested its decision independently on the state constitution but had based its decision on the Fourth and Fourteenth Amendments, having followed the approach, consistent with previous opinions of the Delaware Supreme Court, of interpreting the state constitutional provision in terms of the breadth and scope of the Fourth and Fourteenth Amendments, and (2) a policeman's stopping an automobile and detaining the driver in order to check the driver's license and the registration of the automobile constitute an unreasonable seizure under the Fourth and Fourteenth Amendments, except in those situations in which there is at least an articulable and reasonable suspicion that a motorist is unlicensed, or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, such rule against random stops and detentions, however, not precluding a state from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion, such as, for example, the questioning of all oncomingtraffic at roadblock-type stops.

BLACKMUN, J., joined by POWELL, J., concurred, with the understanding that (1) the court's allowing spot checks that do not involve the unconstrained exercise of discretion would include, in addition to a roadblock stop for all traffic, other stops that were not purely random and that equate with, but are less intrusive than, a 100% roadblock stop, and (2) the court's decision was distinguishable, for purposes of constitutionality, from individualized random examinations by game wardens in the performance of their duties.

REHNQUIST, J., dissenting, expressed the view that the state's system of random spot checks of vehicles was not violative of the Fourth Amendment, and that there was no basis for distinguishing, for Fourth Amendment purposes, between a roadblock stop of all cars and the random stop of a car in order to check the driver's license and the vehicle's registration.

p. 661

Search and Seizure §8 -- random auto stop and detention – license -- and registration check.

la, lb, lc.  A police officer's stopping an automobile and detaining the driver in order to check the driver's license and the registration of the automobile constitute an unreasonable seizure under the Fourth and Fourteenth Amendments, where the police officer has no articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, there being no justification for subjecting every occupant of every vehicle on the roads to a seizure at the unbridled discretion of law-enforcement officials on the basis of a state interest in promoting roadway safety. (Rehnquist, J dissented from this holding.)

Appeal and Error §500 -- Supreme Court jurisdiction -- review of state court decision -- independent and adequate state ground -- police stop of vehicle

2. The United States Supreme Court has jurisdiction to review, on certiorari, the decision of a state's highest court holding that a policeman's random stop of a vehicle violated Fourth and Fourteenth Amendments to the United States Constitution and a provision of the state constitution substantially similar to the Fourth Amendment, and the Supreme Court's jurisdiction is not barred on the ground of the state court's judgment having been based on an independent and adequate state ground, where even if the state constitution would have provided an adequate basis for the judgment, the holding of the state's highest court depended upon its view of the reach of the Fourth and

p.662

Fourteenth Amendments, the state court having followed the approach, consistent with its previous decisions, that the state constitution would automatically be interpreted  at least as broadly as the Fourth Amendment so that every police practice authoritatively determined to be contrary to the Fourth and Fourteenth Amendments would, without further analysis, be held contrary to the state constitutional provision.

      [See annotation p 924, infra]

Appeal and Error §487 -- independent and adequate state ground -- Supreme Court jurisdiction.

3. If the decision of a state's highest court is based solely on the United States Constitution, without mention of state law, the United States Supreme Court will have jurisdiction to review the decision on certiorari, even though the state constitution might have provided an independent and adequate state ground upon which the state court could have based its decision.

Search and Seizure §2 -- stopping automobile.

4. A state police officer's stopping an automobile and detaining its occupants constitute a "seizure" within the meaning  of  the  Fourth  and  Fourteenth Amendments, even though the purpose of the stop is limited and the resulting detention quite brief.

Search and Seizure §5 -- Fourth Amendment  reasonableness.

5. Since the essential purpose of the proscriptions in the Fourth Amendment is to impose a standard of "reasonableness" upon the exercise of discretion by government officials, including law‑enforcement agents, in order to safeguard the privacy and security of individuals against arbitrary invasions, the permissibility of a  particular  law‑enforcement practice is judged by balancing its intrusion on the individual's Fourth Amendment interests against its promotion of legitimate governmental interests.

Search and Seizure §6 -- Fourth Amendment  persons protected persons in autos.

6. An individual operating or traveling in an automobile does not lose all reasonable expectation of privacy simply because the automobile and its use are subject to government regulation, and just as people are not shorn of all Fourth Amendment protection when they step from their homes onto the public sidewalks, nor are they shorn of those interests when they step from the sidewalks into their automobiles.

Search and Seizure §8 -- auto stops -- registration and license checks -- roadblock‑type stops

7. The rule that a police officer's stopping an automobile and detaining the driver in order to check his driver's license and the registration of the automobile constitute an unreasonable seizure  under  the  Fourth  Amendment when there is no articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, does not preclude the state from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion, the questioning of all  oncoming  traffic  at  roadblock‑type stops being one possible alternative.

Search and Seizure §8 -- auto stops -- license and registration checks -- weigh‑stations and inspection points for trucks

8a, 8b. The rule that a police officer's stopping an automobile and detaining the driver in order to check his driver's license and the registration of the automobile constitute an unreasonable seizure  under  the  Fourth  Amendment when there is no articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, does not cast doubt on the permissibility of roadside truck weigh‑stations and inspection points, at which some vehicles may be subject to further detention for safety and regulatory inspection than are others.

p. 663

A patrolman in a police cruiser stopped an automobile occupied by respondent and seized marihuana in plain view on the car floor. Respondent was subsequently indicted for illegal possession of a controlled substance. At a hearing on respondent's motion to suppress the marihuana,  the  patrolman  testified  that prior to stopping the vehicle he had observed neither traffic or equipment violations nor any suspicious activity, and that he made the stop only in order to check the driver's license and the car's registration. The patrolman was not acting pursuant to any standards, guidelines, or procedures pertaining to document spot checks, promulgated by either his department or the State Attorney General. The trial court granted the motion to suppress, finding the stop and detention to have been wholly capricious and therefore violative of the Fourth Amendment. The Delaware Supreme Court affirmed. Held:

  1. This Court has jurisdiction  in this. case even though the Delaware Supreme Court held that the stop at issue not only violated the Federal Constitution but was also impermissible under the Delaware  Constitution.  That  court's opinion shows that even if the state Constitution would have provided an adequate basis for the judgment below, the court did not intend to rest its decision independently on the state Constitution, its .holding instead depending upon its view of the reach of the Fourth and Fourteenth Amendments.

  2. Except where there is at least articulable and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, stopping an automobile and detaining the driver in order to check his driver's license and the registration of the automobile  are  unreasonable  under  the Fourth Amendment.

  (a) Stopping an automobile and detaining its occupants constitute a "seizure" within the meaning of the Fourth and Fourteenth Amendments, even though the purpose of the stop is limited and the resulting detention quite brief. The permissibility of a  particular law enforcement practice is judged by balancing  its  intrusion  on  the  individual's Fourth Amendment interests against its promotion of legitimate governmental interests.

  (b) The State's interest in discretionary spot checks as a means of ensuring the safety of its roadways does not outweigh the resulting intrusion on the privacy and security of the persons detained. Given the physical and psychological intrusion visited upon the occupants of a vehicle by a random stop to check documents, cf. United States v Brignoni‑Ponce, 422 US 873, 45 L Ed 2d 607, 95 S Ct 2574, United States v Martinez‑Fuerte, 428 US 543, 49 L Ed 2d 1116, 96 S Ct 3074, the marginal contribution to  roadway  safety  possibly  resulting from a system of spot checks cannot justify subjecting every occupant of every vehicle on the roads to a seizure at the unbridled discretion of law enforcement officials.

  (c) An individual operating or traveling in an automobile does not lose all reasonable expectation of privacy simply because the automobile and its use are subject to government regulation. People are not shorn of all Fourth Amendment protection when they step from their homes onto the public sidewalk; nor are they shorn of those interests when they step from the sidewalks into their automobiles.

  (d) The holding in this case does not preclude Delaware or other States from developing methods for spot checks that involve less intrusion or that do not involve the unconstrained exercise of discretion. Questioning of all oncoming traffic at roadblock‑type stops is one possible alternative.

382 A2d 1359, affirmed.

White, J delivered the opinion of the Court, in which Burger, C. J and Brennan, Stewart, Marshall, Blackmun, Powell, and Stevens, JJ joined. Blackmun, J filed a concurring opinion, in which Powell, J joined. Rehnquist, J., filed a dissenting opinion.

p. 664

[440 US 650]

 Mr. Justice White delivered the opinion of the Court.

[la] The question is whether it is an unreasonable seizure under the Fourth  and  Fourteenth  Amendments to stop an automobile, being driven on a public highway, for the purpose of checking the driving license of the operator and the registration of the car, where there is neither probable cause to believe nor reasonable suspicion that the car is being driven contrary to the laws governing the operation of motor vehicles or that either the car or any of its occupants is subject to seizure or detention in connection with the violation  of any  other  applicable law.

I

At 7:20 p.m. on November 30, 1976, a New Castle County, Del., patrolman in a police cruiser stopped the automobile occupied by respondent.1 The patrolman smelled marihuana smoke as he was walking toward the stopped vehicle, and he seized marihuana in plain view on the car floor. Respondent was subsequently indicted for illegal possession of a controlled substance. At a hearing on respondent's motion to suppress the marihuana seized as a result of the stop, the patrolman testified that prior to stopping the vehicle  he  had  observed  neither traffic or equipment violations nor any suspicious activity, and that he made the stop only in order to check the driver's license and registration. The patrolman was not acting pursuant to any standards, guidelines, or procedures pertaining to document spot checks, promulgated by either his department or the State Attorney  General.  Characterizing the stop as "routine," the patrolman explained, "I saw the car

                                                            [440 US 651]

                                                                                    in the area and wasn't answering any complaints, so I decided to pull them off." App A9. The trial court granted the motion to suppress, finding the stop and detention to have been wholly capricious and therefore violative of the Fourth Amendment.

The Delaware Supreme Court affirmed, noting first that "[t]he issue of the legal validity of systematic, roadblock‑type stops of a number of vehicles for license and vehicle registration check is not now before the Court," 382 A2d 1359, 1362 (1978) (emphasis in original). (The court held that "a random stop of a motorist in the absence of specific articulable facts which justify the stop by indicating a reasonable suspicion that a violation of the law has occurred is constitutionally impermissible and violative of the Fourth and Fourteenth  Amendments  to  the

p. 665

United States Constitution.?' Id., at 1364. We granted certiorari to resolve the conflict between this decision, which is in accord with decisions in five other jurisdictions,2 and the contrary determination in six jurisdictions3 that the Fourth Amendment does not prohibit the kind of automobile stop that occurred here. 439 US 816, 58 L Ed 2d 107, 99 S Ct 76 (1978).

II

[2] Because the Delaware Supreme Court held that the stop at issue not only violated the Federal Constitution but was

                                                [440 US 652]

                                                                        also impermissible under Art 1, 6, of the Delaware Constitution, it is urged that the judgment below was based on an independent and adequate' state ground and that we therefore have no jurisdiction in this case. Fox Film Corp. v Muller, 296 US 207, 210, 80 L Ed 158, 56 S Ct 183 (1935). At least, it is suggested, the matter is sufficiently uncertain that we should remand for clarification as to the ground upon which the judgment rested. California v Krivda, 409 US 33, 35, 34 L Ed 2d 45, 93 S Ct 32 (1972). Based on our reading of the opinion, however, we are satisfied that even if the state Constitution would have provided an adequate basis for the judgment, the Delaware Supreme Court did not intend to rest its decision independently on the state Constitution and that we have jurisdiction of this case.

[3] As we understand the opinion below, Art 1, 6, of the Delaware Constitution will automatically be interpreted at least as broadly as the Fourth Amendment;4 that is, every police practice authoritatively determined to be contrary to the Fourth and Fourteenth Amendments will, without further analysis, be held to be contrary to Art I,  6. This approach, which is consistent with previous opinions of the Delaware Supreme Court,5 was followed in this

p. 666

case. The court analyzed

[440 US 653]

                                                            the various decisions  interpreting the  Federal Constitution,  concluded  that  the Fourth Amendment foreclosed spot checks of automobiles, and summarily held that the state Constitution was therefore also infringed. This is one of those cases where "at the very least, the [state] court felt compelled by what it understood to be federal constitutional considerations to construe . . . its own law in the manner it did." Zacchini v Scripps Howard Broadcasting Co., 433 US 562, 568, 53 L Ed 2d 965, 97 S Ct 2849, 5 Ohio Ops 3d 215 (1977). Had state law not been mentioned at all, there would be no question about our jurisdiction, even though the state Constitution might have provided an independent and adequate state ground. Ibid. The same result should follow here where the state constitutional holding depended upon the state court's view of the reach of the Fourth and Fourteenth Amendments. If the state court misapprehended federal law, "[i]t should befreed to decide . . . these suits according to its own local law." Missouri ex rel. Southern R. Co. v Mayfield,340 US 1, 5, 95 L Ed 3, 71S Ct 1 (1950).

III

[4, 5] The Fourth and Fourteenth Amendments are implicated in this case because stopping an automobile and detaining its occupants constitute a "seizure" within the meaning of those Amendments, even though the purpose of the stop is limited and he resulting detention quite brief. United  States  v  Martinez-Fuerte, 428 US 543, 556‑558, 49 L Ed 2d 1116, 96 S Ct 3074 (1976); United States v Brignoni‑Ponce, 422 US 873, 878, 45 L Ed 2d 607, 95 S Ct 2574 (1975); cf. Terry v Ohio, 392 US 1, 16, 20 L Ed 2d 889, 88 S Ct 1868, 44 Ohio Ops 2d 383 (1968). The essential purpose of the proscriptions in the Fourth Amendment is to impose a standard

                                                [440 US 654]

                                                            of "reasonableness"6 upon the exercise of discretion by government officials, including law enforcement agents, in order " 'to safeguard the privacy and security of individuals against arbitrary invasions.  . . .' "  Marshall  v  Barlow's, Inc., 436 US 307, 312, 56 L Ed 2d 305, 98 S Ct 1816 (1978), quoting Camara v Municipal Court, 387 US 523, 528, 18 L Ed 2d 930, 87 S Ct 1727 (1967).7 Thus, the permissibility of  a  particular  law  enforcement practice is judged by balancing its intrusion on the individual's Fourth Amendment interests against its promotion of legitimate governmen‑

p. 667

tal interests.8 Implemented  in  this manner, the reasonableness standard usually requires, at a minimum, that the facts upon which an intrusion is based be capable of measurement against "an objective standard,”9  whether  this  be  probable cause10 or a less stringent test.11 In those situations in which the balance of interests precludes insistence upon "some quantum

[440 US 655]

of individualized  suspicion."12 other  safeguards are generally relied upon to assure that the individual's reasonable expectation of privacy is not "subject to the discretion of the official in the field."  Camara  v  Municipal  Court, 387 US, at 532, 18 L Ed 2d 930, 87 S Ct 1727. See id., at 534‑535, 18 L Ed 2d 930, 97 S Ct 1727; Marshall v Barlow's, Inc., supra, at 320‑321, 56 L Ed 2d 305, 98 S Ct 1816; United States  v  United  States  District Court, 407 US 297, 322‑323, 32 L Ed 2d 752, 92 S. Ct 2125 (1972) (requiring warrants).

In this case, however, the State of Delaware urges that patrol officers be subject to no constraints in deciding which automobiles shall be stopped for a license and registration check because the Slate's interest in discretionary spot checks as a means of ensuring the safety of its roadways outweighs the resulting intrusion on the privacy and security of the persons detained.

IV

 We have only recently considered the legality of investigative stops of automobiles where the officers making the stop have neither probable cause to believe nor reasonable suspicion that either the automobile or its occupants are subject to seizure under the applicable criminal laws. In United States v Brignoni‑Ponce, supra. Border Patrol agents conducting roving patrols in areas near the international border asserted statutory authority to stop at random any vehicle  in  order  to  determine whether it contained illegal aliens or was involved in smuggling operations. The practice was held to violate the Fourth Amendment, but the Court did not invalidate all warrantless automobile stops upon less than probable cause. Given "the importance of the governmental interest at stake, the minimal intrusion of a

p. 668 

brief stop, and the absence of practical alternatives for policing the border," 422 US, at 881, 45 L Ed 2d 607, 95 S Ct 2574, the Court analogized the roving‑patrol stop to the on‑thestreet encounter addressed in Terry v Ohio, supra, and held:

"Except at the border and its functional equivalents, officers on roving patrol may stop vehicles only if they are

[440 US 656]

aware of specific articulable facts,  together with  rational inferences from those facts, that reasonably 'warrant suspicion that the vehicles contain aliens who may be illegally in the country." 422 US, at 884, 45 L Ed 2d 607, 95 S Ct 2574 (footnote omitted).

Because "the nature of illegal alien traffic and the characteristics of smuggling operations tend to generate articulable grounds for identifying violators," id., at 883, 45 L Ed 2d 607, 95 S Ct 2574, "a requirement of reasonable suspicion for stops allows the Government adequate means of guarding the public interest and also protects  residents  of  the  border areas from indiscriminate official interference." Ibid.

The constitutionality of stops by Border Patrol agents was again before the Court in United States v Martinez‑Fuerte, supra, in which we addressed the permissibility of checkpoint operations. This practice involved slowing all oncoming traffic "to  a virtual,  if not  a  complete, halt," 428 US, at 546, 49 L Ed 2d 1116, 96 S Ct 3074, at a highway roadblock,  and  referring  vehicles chosen at the discretion of Border Patrol agents to an area for secondary inspection. See id., at‑ 546, 558, 49 L Ed 2d 1116, 96 S Ct 3074. Recognizing that the governmental interest involved was the same as that  furthered  by  roving‑patrol stops,  the  Court  nonetheless  sustained .the constitutionality of the Border Patrol's checkpoint operations. The crucial distinction was the lesser intrusion upon the motorist's Fourth Amendment interests:

"[The]  objective  intrusion -- the stop itself, the questioning, and the visual inspectionalso existed in roving‑patrol stops. But we view checkpoint stops in  a different light because the subjective intrusionthe generating of concern or even fright on the part of lawful travelersis appreciably less in the case of a checkpoint stop." Id., at 558, 49 L Ed 2d 1116, 96 S Ct 3074.

Although not dispositive,13 these decisions undoubtedly provide

[440 US 657]

guidance in balancing the public interest against  the  individual's  Fourth Amendment interests implicated by the practice of spot checks such as occurred in this case. We cannot agree that stopping or detaining a vehicle on an ordinary city street is less intrusive than a roving‑patrol stop on a major highway and that it bears greater resemblance to a permissible stop and secondary detention at a checkpoint near the border. In this regard, we note that Brignoni‑Ponce was not limited to roving patrol stops on limited access roads,

p. 669

but applied to any roving‑patrol stop by Border Patrol agents on any type of roadway on less than reasonable suspicion. See 422 US, at 882‑883, 45 L Ed 2d 607, 95 S Ct 2574; United States v Ortiz, 422 US 891, 894, 45 L Ed 2d 623, 95 S Ct 2585 (1975). We cannot assume that the physical and psychological intrusion visited upon the occupants of a vehicle by a random stop to check documents is of any less moment than that occasioned by a stop by border agents on roving patrol. Both of these stops generally entail law enforcement officers signaling a moving automobile to pull over to the side of the roadway, by means of a possibly unsettling show of authority. Both interfere with freedom of movement, are inconvenient,  and  consume  time. Both may create substantial anxiety. For Fourth Amendment purposes, we also see insufficient resemblance between sporadic and random stops of individual vehicles making their way through city traffic and those stops occasioned by roadblocks where all vehicles are brought to a halt or to a near halt, and all are subjected to a show of the police power of the community. "At traffic checkpoints the motorist can see that other vehicles are being stopped, he can see visible signs of the officers' authority, and he is much less likely to be frightened or annoyed by the intrusion." Id., at 894895, 45 L Ed 2d 623, 95 S Ct 2585, quoted in United States v Martinez-Fuerte, 428 US, at 558, 49 L Ed 2d 1116, 96 S Ct 3074.

[440 US 658]

But the State of Delaware urges that  even  if  discretionary  spot checks such as occurred in this case intrude upon motorists as much as or more than do the roving patrols held  impermissible in Brignoni-Ponce, these stops are reasonable under the Fourth Amendment because the State's interest in the practice as a means of promoting public safely upon its roads more than outweighs the intrusion entailed. Although the record discloses no statistics concerning the extent of the problem of lack of14 highway safety, in Delaware or in the Nation as a whole, we are aware of the danger to life" and property posed by vehicular traffic and of the difficulties that even a cautious and an experienced driver may encounter. We agree that the States have a vital interest in ensuring that only those qualified to do so are permitted to operate motor vehicles, that these vehicles are fit for safe operation, and hence that licensing, registration, and vehicle inspection requirements are being observed. Automobile licenses are issued periodically to evidence that the drivers holding them .are sufficiently familiar with the rules of the road and are physically qualified to operate a motor vehicle.15 The registration requirement and, more pointedly, the related annual inspection requirement in Delaware'16 are designed to keep dangerous automobiles off the road. Unquestionably, these provisions, properly administered, are es‑

p. 670

sential elements in a highway safety program. Furthermore, we note that the State of Delaware requires a minimum amount of insurance

[440 US 659]

coverage as a condition to automobile registration,17 implementing its legitimate interest in seeing to it that its citizens  have  protection  when  involved in a motor vehicle accident.18

 The question remains, however, whether in the service of these important ends the discretionary spot check is a sufficiently productive mechanism to justify the intrusion upon Fourth Amendment interests which such stops entail. On the record before us, that question must be answered in the negative. Given the alternative  mechanisms  available, both those in use and those that might be adopted, we are unconvinced that the incremental countribution to highway safety of the random spot check justifies the practice under the Fourth Amendment.

 The foremost method of enforcing traffic and vehicle safety regulations, it must be recalled, is acting upon observed violations.' Vehicle stops for traffic   violations   occur  countless times each day; and on these occasions, licenses and registration papers are subject to inspection and drivers without them will be ascertained. Furthermore, drivers without licenses are presumably the less safe drivers whose propensities may well exhibit  themselves.19 Absent  some empirical data to the contrary, it must be assumed that finding an unlicensed driver among those who commit traffic violations is a much more likely event than finding an unlicensed driver by choosing randomly from the entire universe of drivers. If this were not so, licensing of drivers would hardly be an effective means of promoting roadway safety. It seems common sense that the

[40 US 660]

                        percentage of all drivers on the road who are driving without a license is very small and that the number of licensed drivers who will be stopped in order to find one unlicensed operator will be large indeed. The contribution to highway safety made by discretionary stops selected from among drivers generally will therefore be marginal at best. Furthermore, and again absent something more than mere assertion to the contrary, we find it difficult to believe that the unlicensed driver would not be deterred by the possibility of being involved in a traffic violation or having some other experience calling for proof of his entitlement to drive but that he would be deterred by the possibility that he would be one of those chosen for a spot check. In terms of actually discovering unlicensed drivers or deterring them from driving, the spot check does not appear sufficiently productive to qualify as a reasonable law enforcement practice under the Fourth Amendment.

Much the same can be said about the safety aspects of automobiles as

 p. 671

distinguished from drivers. Many violations of minimum vehicle‑safety requirements are observable, and something can be done about them by the observing officer, directly and immediately. Furthermore, in Delaware, as elsewhere, vehicles must carry and display current license plates,20 which themselves evidence that the vehicle is properly registered;21 and, under Delaware law, to qualify for annual registration a vehicle must pass the annual safety inspection22 and  be properly insured.23 It does not appear, therefore, that a stop of a Delaware‑registered vehicle is necessary in order to ascertain compliance with the State's registration requirements and because there is nothing to

[440 US 661]

show that a significant percentage of automobiles from other States do not also require license plates indicating current registration, there is no basis for concluding that stopping even out‑of‑state cars for document checks substantially promotes the State's interest.

[ [1b] The marginal contribution to roadway safety possibly resulting from a system of spot checks cannot justify subjecting every occupant of every vehicle on the roads to a seizure limited in magnitude compared to other intrusions but nonetheless constitutionally cognizable at the unbridled discretion of law enforcement officials. To insist neither upon an appropriate factual basis for suspicion directed at a particular automobile nor upon some other substantial and objective standard or rule to govern the exercise of discretion "would  invite intrusions upon constitutionally guaranteed rights based on nothing more substantial  than  inarticulate hunches . . . ." Terry v Ohio, 392 US, at 22, 20 L Ed 2d 889, 88 S Ct 1868, 44 Ohio Ops 2d 383. By hypothesis,  stopping  apparently  safe drivers is necessary only because the danger presented by some drivers is not observable at the time of the stop.  When  there is not probable cause to believe that a driver is violating any one of the multitude of applicable traffic and equipment regulations24 or other articulable basis amounting to reasonable suspicion that the driver is unlicensed or his vehicle unregistered we cannot conceive  of any  legitimate  basis upon which a patrolman could decide  that  stopping  a  particular driver for a spot check would be more productive than stopping any other driver. This kind of standardless and unconstrained discretion is the evil the Court has discerned when in previous cases it has insisted that the discretion of the official in the field be circumscribed, at least to some extent. Almeida‑Sanchez v United States, 413 US 266, 270, 37 LEd2d 596, 93 S Ct 2535 (1973); Camara v Municipal Court, 387 US, at 532‑533, 18 LEd2d 930, 87 S Ct 1727.

[440 US 662]

VI

The "grave danger" of abuse of discretion. United States v MartinezFuerte, 428 US, at 559, 49 LEd2d 1116, 96 S Ct 3074, does not disappear simply because the automobile is subject to state regulation result‑

 p. 672

ing in numerous instances of police citizen contact. Cady v Dombrowski, 413 US 433, 441, 37 L Ed 2d 706, 93. S Ct 2523 (1973). Only last Term we pointed out that "if the government intrudes . . . the privacy interest suffers  whether  the  government's motivation is to investigate violations of criminal laws or breaches of other statutory or regulatory standards." Marshall v Barlow's, Inc., 436 US, at 312‑313, 56 L Ed 2d 305, 98 S Ct 1816. There are certain "relatively unique circumstances," id., at 313, 56 L Ed 2d 305, 98 S Ct 1816, in which consent to regulatory restrictions  is presumptively  concurrent with participation in the regulated enterprise. See United States v Biswell, 406 US 311, 32 L Ed 2d 87, 92 S Ct 1593 (1972) (federal regulation of  firearms);  Colonnade  Catering Corp. v United States, 397 US 72, 25 L Ed 2d 60, 90 ,S Ct 774 (1970) (federal regulation of liquor). Otherwise,  regulatory  inspections  unaccompanied by any quantum of individualized, articulable suspicion must be undertaken pursuant to previously specified "neutral criteria." Marshall v Barlow's, Inc., supra, at 323, 56 L Ed 2d 305, 98 S Ct 1816.

  [6]  An  individual  operating  or traveling in an automobile does not lose all reasonable expectation of privacy simply because the automobile and its use are subject to government  regulation.25 Automobile travel is a basic, pervasive, and often necessary mode of transportation to and from one's home, workplace, and leisure activities. Many people spend more hours each day traveling in cars than walking on the streets.

Undoubtedly, many find a greater sense of security and privacy in, traveling in an automobile than they do in  exposing themselves  by  pedestrian or other modes of travel. Were the

[440 US 963]

individual subject to unfettered governmental intrusion every time he entered an automobile, the security guaranteed by the Fourth Amendment would be seriously circumscribed. As Terry v Ohio, supra, recognized, people are not shorn of all  Fourth  Amendment  protection when they step from their homes onto the public sidewalks. Nor are they shorn of those interests when they step from the sidewalks into their automobiles. See Adams v Williams, 407 US 143, 146, 32 L Ed 2d 612, 92 S Ct 1921 (1972).

VII

[ lc, 7, 8a]  Accordingly,  we  hold that except in those situations in which there is at least articulable. and reasonable suspicion that a motorist is unlicensed or that an automobile is not registered, or that either the vehicle or an occupant is otherwise subject to seizure for violation of law, stopping an automobile and detaining the driver in order to check his driver's license and the registration of the automobile are unreasonable under the Fourth Amendment. This holding does not preclude the State of Delaware or other States from developing methods for spot checks that invovle less intrusion or that do not involve the unconstrained exercise of

p. 673

discretion.26

Questioning  of  all  oncoming traffic at roadblock‑type stops is one possible alternative. We hold only that persons in automobiles on public roadways may not for that reason alone have their .travel and privacy interfered with at the unbridled discretion of police. The judgment below is affirmed.

  So ordered.

Mr.  Justice  Blackmun,  with whom Mr. Justice Powell joins, concurring.

  The Court, ante, at this page, 59 L Ed 2d, at 673, carefully protects from the reach of its decision other less intrusive spot checks "that do not involve

[440 US 664]

the unconstrained exercise of discretion."  The  roadblock  stop  for  all traffic is given as an example. I necessarily assume that the Court's reservation  also  includes  other  not purely random stops (such as every 10th car to pass a given point) that equate with, but are less intrusive than, a 100% roadblock stop. And I would not regard the present case as a precedent that throws any constitutional shadow upon the necessarily somewhat individualized and perhaps largely random examinations by game wardens in the performance of their duties. In a situation of that type, it seems to me, the Court's balancing process, and the value factors under consideration, would be quite different.

With this understanding, I join the Court's opinion and its judgment.

 Mr. Justice Rehnquist, dissenting.

The Court holds, in successive sentences, that absent an articulable, reasonable  suspicion  of  unlawful conduct, a motorist may not be subjected to a random license check, but that the States are free to develop "methods