dissenting in part.
If enforced as written, the ordinance at issue in this case will eliminate the outdoor advertising business in the city of San Diego.1 The principal question presented is, therefore, whether a city may prohibit this medium of communication. Instead of answering that question, the plurality focuses its attention on the exceptions from the total ban and, somewhat ironically, concludes that the ordinance is an unconstitutional abridgment of speech because it does not abridge enough speech.2
*541The plurality first holds that a total prohibition of the use of “outdoor advertising display signs” 3 for commercial messages, other than those identifying or promoting a business located on the same premises as the sign, is permissible. I agree with the conclusion that the constitutionality of this prohibition is not undercut by the distinction San Diego has drawn between onsite and offsite commercial signs, see ante, at 512 (plurality .opinion), and I therefore join Parts I through IV of Justice White’s opinion. I do not, however, agree with the reasoning which leads the plurality to invalidate the ordinance because San Diego failed to include a total ban on the use of billboards for both commercial and noncommercial messages. While leaving open the possibility that a total ban on billboards would be permissible, see ante, at 515, n. 20,4 the plurality finds two flaws in the ordinance. First, because the ordinance permits commercial, but not noncommercial, use of onsite signs, it improperly “afford [s] a greater degree of protection to commercial than to noncommercial speech.” Ante, at 513. And, second, because the ordinance excepts certain limited categories of noncommercial signs from the prohibition, the city is guilty of “choos[ing] the appropriate subjects for public discourse.” Ante, at 515.
*542Although it is possible that some future applications of the San Diego ordinance may violate the First Amendment, I am satisfied that the ordinance survives the challenges that these appellants have standing to raise. Unlike the plurality, I do not believe that this case requires us to decide any question concerning the kind of signs a property owner may display on his own premises. I do, however, believe that it is necessary to confront the important question, reserved by the plurality, whether a city may entirely ban one medium of communication. My affirmative answer to that question leads me to the conclusion that the San Diego ordinance should be upheld; that conclusion is not affected by the content-neutral exceptions that are the principal subject of the debate between the plurality and The Chief Justice.
I
Appellants are engaged in the outdoor advertising business. The parties stipulated that there are critical differences between that business and so-called "onsite” or business signs.5 *543Outdoor advertising is presented on large, standardized billboards which display a variety of commercial and noncommercial messages that change periodically.6 The only information in the record about onsite signs is that they “advertise businesses, goods or services available on the property on which the sign is located.” Joint Stipulation of Facts No. 22, App. 45a. There is no evidence that any onsite signs in San Diego of the permanent character covered by the ordinance 7 have ever been used for noncommercial messages.
If the ordinance is enforced, two consequences are predictable. Appellants’ large and profitable outdoor advertising businesses will be destroyed.8 Moreover, many persons who *544now rent billboards to convey both commercial and noncommercial messages to the public will not have access to an equally effective means of communication.9 There is no evidence, however, that enforcement of the ordinance will have any effect whatsoever upon any property owner’s use of on-site advertising signs.10 Nor is there anything in the record to suggest that the use of onsite signs has had any effect on the outdoor advertising business or on any of the consumers of offsite billboard space.
Appellants, of course, have standing to challenge the ordinance because of its impact on their own commercial operations. Because this challenge is predicated in part on the First Amendment, I agree with the plurality and Justice Brennan that they also have standing to argue that the ordinance is invalid because of its impact on their customers— the persons who use their billboards to communicate with the public. See ante, at 504, n. 11 (plurality opinion). I do not agree, however, that they have any standing to assert the purely hypothetical claims of property owners whose on-site advertising is entirely unaffected by the application of the ordinance at issue in this case.
*545This case involves only the use of permanent signs in areas zoned for commercial and industrial purposes.11 It is conceivable that some public-spirited or eccentric businessman might want to use a permanent sign on his commercial property to display a noncommercial message. The record, however, discloses no such use in the past, and it seems safe to assume that such uses in the future will be at best infrequent. Rather than speculate about hypothetical cases that may be presented by property owners not now before the Court, I would judge this ordinance on the basis of its effect on the outdoor advertising market and save for another day any questions concerning its possible effect in an entirely separate market.
The few situations in which constitutional rights may be asserted vicariously represent exceptions from one of the Court’s most fundamental principles of constitutional adjudication.12 Our explanation of that principle in Broadrick v. Oklahoma, 413 U. S. 601, 610-611 (footnote omitted), merits emphasis and repetition:
“Embedded in the traditional rules governing constitutional adjudication is the principle that a person to whom a statute may constitutionally be applied will not be heard to challenge that statute on the ground that it may conceivably be applied unconstitutionally to others, *546in other situations not before the Court. See, e. g., Austin v. The Aldermen, 7 Wall. 694, 698-699 (1869); Supervisors v. Stanley, 105 U. S. 305, 311-315 (1882) ; Hatch v. Reardon, 204 U. S. 152, 160-161 (1907); Yazoo & M. V. R. Co. v. Jackson Vinegar Co., 226 U. S. 217, 219-220 (1912); United States v. Wurzbach, [280 U. S.], at 399; Carmichael v. Southern Coal & Coke Co., 301 U. S. 495, 513 (1937); United States v. Raines, 362 U. S. 17 (1960). A closely related principle is that constitutional rights are personal and may not be asserted vicariously. See McGowan v. Maryland, 366 U. S. 420, 429-430 (1961). These principles rest on more than the fussiness of judges. They reflect the conviction that under our constitutional system courts are not roving commissions assigned to pass judgment on the validity of the Nation’s laws. See Younger v. Harris, 401 U. S. 37, 52 (1971). Constitutional judgments, as Mr. Chief Justice Marshall recognized, are justified only out of the necessity of adjudicating rights in particular cases between the litigants brought before the Court:
“'So if a law be in opposition to the constitution; if both the law and the constitution apply to a particular case, so that the court must either decide that case con-formably to the law, disregarding the constitution; or conformably to the constitution, disregarding the law; the court must determine which of these conflicting rules governs the case. This is of the very essence of judicial duty.’ Marbury v. Madison, 1 Cranch 137, 178 (1803).
“In the past, the Court has recognized some limited exceptions to these principles, but only because of the most 'weighty countervailing policies.’ United States v. Raines, 362 U. S., at 22-23.”
The most important exception to this standing doctrine permits some litigants to challenge on First Amendment grounds laws that may validly be applied against them but *547which may, because of their unnecessarily broad reach, inhibit the protected speech of third parties. That exception plays a vital role in our First Amendment jurisprudence.13 But it is nonetheless a limited exception. Because “ [application of the overbreadth doctrine ... is, manifestly, strong medicine," it is employed “sparingly and only as a last resort.” Broadrick, 413 U. S., at 613. As the Court explained in Broadrick, the doctrine will be applied only if the overbreadth of a statute is substantial in relation to its “plainly legitimate sweep”:
“Although such laws, if too broadly worded, may deter protected speech to some unknown extent, there comes a point where that effect — at best a prediction — cannot, with confidence, justify invalidating a statute on its face and so prohibiting a State from enforcing the statute against conduct that is admittedly within its power to proscribe. Cf. Alderman v. United States, 394 U. S. 165, 174-175 (1969). To put the matter another way, particularly where conduct and not merely speech is involved, we believe that the overbreadth of a statute must not only be real, but substantial as well, judged in relation to the statute’s plainly legitimate sweep. It is our view that § 818 is not substantially overbroad and that whatever overbreadth may exist should be cured through case-by-case analysis of the fact situations to which its sanctions, assertedly, may not be applied.” Id., at 615-616 (footnote omitted).14
*548In my judgment, the likelihood that the San Diego ordinance will have a significant adverse impact on the users of onsite signs is sufficiently speculative and remote that I would not attempt to adjudicate the hypothetical claims of such parties on this record. Surely the interests of such parties do not necessarily parallel the interests of these appellants.15 Moreover, changes in the provisions of the ordinance concerning onsite advertising would not avoid the central question that is presented by appellants’ frontal attack on the application of the ordinance to their own businesses and to their customers.16 I believe the Court should decide that question and put the hypothetical claims of onsite advertisers entirely to one side.
II
Just as the regulation of an economic market may either enhance or curtail the free exchange of goods and services,17 so may regulation of the communications market sometimes facilitate and sometimes inhibit the exchange of information, ideas, and impressions. Procedural rules in a deliberative body are designed to improve the quality of debate. Our *549cases upholding regulation of the time, place, or manner of communication have been decided on the implicit assumption that the net effect of the regulation on free expression would not be adverse. In this case, however, that assumption cannot be indulged.
The parties have stipulated, correctly in my view,18 that the net effect of the city’s ban on billboards will be a reduction in the total quantity of communication in San Diego. If the ban is enforced, some present users of billboards will not be able to communicate in the future as effectively as they do now.19 This ordinance cannot, therefore, be sustained on the assumption that the remaining channels of communication will be just as effective for all persons as a communications marketplace which includes a thousand or more large billboards available for hire.
The unequivocal language of the First Amendment prohibits any law “abridging the freedom of speech.” That language could surely be read to foreclose any law reducing the quantity of communication within a jurisdiction. I am convinced, however, that such a reading would be incorrect. My conviction is supported by a hypothetical example, by the Court’s prior cases, and by an appraisal of the healthy character of the communications market.
Archaeologists use the term “graffiti” to describe informal inscriptions on tombs and ancient monuments. The graffito was familiar in the culture of Egypt and Greece, in the Italian decorative art of the 15th century, and it survives today in some subways and on the walls of public buildings.20 It is *550an inexpensive means of communicating political, commercial, and frivolous messages to large numbers of people; some creators of graffiti have no effective alternative means of publicly expressing themselves. Nevertheless, I believe a community has the right to decide that its interests in protecting property from damaging trespasses and in securing beautiful surroundings outweigh the countervailing interest in uninhibited expression by means of words and pictures in public places. If the First Amendment categorically protected the marketplace of ideas from any quantitative restraint, a municipality could not outlaw graffiti.
Our prior decisions ,are n.ot inconsistent with this proposition. Whether one interprets the Court’s decision in Kovacs v. Cooper, 336 U. S. 77, as upholding a total ban on the use of sound trucks, or merely a ban on the “loud and raucous” use of amplifiers, the case at least stands for the proposition that a municipality may enforce a rule that curtails the effectiveness of a particular means of communication.21 Even the dissenting Justices in that case thought it obvious that “cities may restrict or absolutely ban the use of amplifiers on busy streets in the business area.” Id., at 104 (Black, J., joined by Douglas and Rutledge, JJ., dissenting).22 Kovacs, I be*551lieve, forecloses any claim that a prohibition of billboards must fall simply because it has some limiting effect on the communications market.23
*552I therefore assume that some total prohibitions may be permissible. It seems to be accepted by all that a zoning regulation excluding billboards from residential neighborhoods is justified by the interest in maintaining pleasant surroundings and enhancing property values. The same interests are at work in commercial and industrial zones. Reasonable men may assign different weights to the conflicting interests, but in constitutional terms I believe the essential inquiry is the same throughout the city. For whether the ban is limited to residential areas, to the entire city except its most unsightly sections, or is citywide, it unquestionably will limit the quantity of communication. Moreover, the interests served by the ban are equally legitimate and substantial in all parts of the city. Those interests are both psychological and economic. The character of the environment affects property values and the quality of life not only for the suburban resident but equally so for the individual who toils in a factory or invests his capital in industrial properties.
Because the legitimacy of the interests supporting a citywide zoning plan designed to improve the entire municipality are beyond dispute, in my judgment the constitutionality of the prohibition of outdoor advertising involves two separate questions. First, is there any reason to believe that the regulation is biased in favor of one point of view or another, or that it is a subtle method of regulating the controversial subjects that may be placed on the agenda for public debate? Second, is it fair to conclude that the market which remains open for the communication of both popular and unpopular ideas is ample and not threatened with gradually increasing restraints?
In this case, there is not even a hint of bias or censorship in the city’s actions. Nor is there any reason to believe that the overall communications market in San Diego is inade*553quate. Indeed, it may well be true in San Diego as in other metropolitan areas that the volume of communication is excessive and that the public is presented with too many words and pictures to recognize those that are most worthy of attention. In any event, I agree with The Chief Justice that nothing in this record suggests that the ordinance poses a threat to the interests protected by the First Amendment.
Ill
If one is persuaded, as I am, that a wholly impartial total ban on billboards would be permissible,24 it is difficult to understand why the exceptions in San Diego's ordinance present any additional threat to the interests protected by the First Amendment. The plurality suggests that, because the exceptions are based in part on the subject matter of noncommercial speech, the city somehow is choosing the permissible subjects for public debate. See ante, at 515. While this suggestion is consistent with some of the broad dictum in Consolidated Edison Co. v. Public Service Comm’n, 447 U. S. 530, it does not withstand analysis in this case.
The essential concern embodied in the First Amendment is that government not impose its viewpoint on the public or select the topics on which public debate is permissible. The San Diego ordinance simply does not implicate this concern. Although Consolidated Edison broadly identified regulations based on the subject matter of speech as impermissible content-based regulations, essential First Amendment concerns *554were implicated in that case because the government was attempting to limit discussion of controversial topics, see id., at 533, and thus was shaping the agenda for public debate. The neutral exceptions in the San Diego ordinance do not present this danger.
To the extent that the exceptions relate to subject matter at all,25 I can find no suggestion on the face of the ordinance that San Diego is attempting to influence public opinion or to limit public debate on particular issues. Except for the provision allowing signs to be used for political campaign purposes for limited periods, see § 101.0700 (F)(12), none of the exceptions even arguably relates to any controversial subject matter. As a whole they allow a greater dissemination of information than could occur under a total ban. Moreover, it was surely reasonable for the city to conclude that exceptions for clocks, thermometers, historic plaques, and the like, would have a lesser impact on the appearance of the city than the typical large billboards.
The exception for political campaign signs presents a different question. For I must assume that these signs may be *555just as unsightly and hazardous as other offsite billboards. Nevertheless, the fact that the community places a special value on allowing additional communication to occur during political campaigns is surely consistent with the interests the First Amendment was designed to protect. Of course, if there were reason to believe that billboards were especially useful to one political party or candidate, this exception would be suspect. But nothing of that sort is suggested by this record. In the aggregate, therefore, it seems to me that the exceptions in this ordinance cause it to have a less serious effect on the communications market than would a total ban.
In sum, I agree with The Chief Justice that nothing more than a rather doctrinaire application of broad statements that were made in other contexts may support a conclusion that this ordinance is unconstitutional because it includes a limited group of exceptions that neither separately nor in the aggregate compromise “our zealous adherence to the principle that the government may not tell the citizen what he may or may not say.” Young v. American Mini Theatres, Inc., 427 U. S. 50, 63 (opinion of Stevens, J.). None of the exceptions is even arguably “conditioned upon the sovereign’s agreement with what a speaker may intend to say.” Ibid. Accordingly, and for the reasons stated in greater detail by The Chief Justice, I respectfully dissent.
The parties so stipulated. See Joint Stipulation of Facts No. 2, App. 42a, quoted in n. 8, infra.
That is the effect of both Justice White’s reaction to the exceptions from a total ban and Justice Brennan’s’ concern about the city’s attempt to differentiate between commercial and noncommercial messages, although *541both of their conclusions purportedly rest on the character of the abridgment rather than simply its quantity.
The ordinance does not define the term “outdoor advertising display signs.” The California Supreme Court adopted the following definition to avoid overbreadth problems:
“ '[A] rigidly assembled sign, display, or device permanently affixed to the ground or permanently attached to a building or other inherently permanent structure constituting, or used for the display of, a commercial or other advertisement to the public.’ ” 26 Cal. 3d 848, 856, n. 2, 610 P. 2d 407, 410, n. 2 (1980).
As a practical matter, the plurality may well be approving a total ban on billboards, or at least on offsite billboards. For it seems unlikely that the outdoor advertising industry will be able to survive if its only customers are those persons and organizations who wish to use billboards to convey noncommercial messages. See ante, at 536, n, 13 (Brennan, J., concurring in judgment).
The parties’ stipulation described these differences:
“There is a difference between the outdoor advertising business and 'on-site’ or business signs. On-site signs advertise businesses, goods or services available on the property on which the sign is located. On the other hand, the outdoor advertising businesses lease real property and erect signs thereon which are made available to national and local advertisers for commercial, political and social messages. Outdoor advertising is different from on-site advertising in that:
“(a) The outdoor advertising sign seldom advertises goods or services sold or made available on the premises on which the sign is located.
“(b) The outdoor advertising sign seldom advertises products or services sold or made available by the owner of the sign.
“(e) The outdoor advertising sign is, generally speaking, made available to 'all-comers’, in a fashion similar to newspaper or broadcasting advertising. It is a forum for the communication of messages to the public.
“(d) The copy of the outdoor advertising sign changes, usually monthly. For example, a particular sign may advertise a local savings and loan association one month, a candidate for mayor the next month, the San Diego Zoo the third month, a new car the fourth month, and a union *543grievance the fifth month.” Joint Stipulation of Facts No. 22, App. 45a-46a.
The importance of the distinction between the outdoor advertising business in which appellants are engaged and the use of "onsite” signs is supported by the fact that the respective kinds of signs are produced by different manufacturers. See Justice BreNNán’s opinion concurring in the judgment, ante, at 526, n. 5.
The physical characteristics of outdoor advertising signs were established by stipulation:
“Outdoor advertising is presented in two basic standardized forms. A ‘poster panel’ is a 12-foot by 24-foot sign on which a pre-printed message is posted, in sheets. A ‘painted bulletin’ is generally a 14-foot by 48-foot sign which contains a hand painted message.” Joint Stipulation of Facts No. 25, App. 47a.
The California Supreme Court’s narrowing construction of the ordinance, see n. 3, supra, makes it applicable only to rigidly assembled permanent signs. For that reason, the plurality is able to state that it deals only “with the law of billboards.” Ante, at 501.
The parties stipulated to the economic effects of the ordinance:
“If enforced as written, Ordinance No. 10795 will eliminate the outdoor advertising business in the City of San Diego.
“Plaintiffs’ outdoor advertising displays produce substantial gross annual income.
“Enforcement of Ordinance No. 10795 will prevent plaintiffs from engaging in the outdoor advertising business in the City of San Diego and *544will cause plaintiffs to suffer substantial monetary losses.” Joint Stipulation of Facts Nos. 2, 26, 32, App. 42a, 48a, 49a.
By stipulation, the parties agreed that the San Diego ordinance will limit the ability of some billboard users to communicate their messages to the public:
“Outdoor advertising increases the sales of products and produces numerous direct and indirect benefits to the public. Valuable commercial, political and social information is communicated to the public through the use of outdoor advertising. Many businesses and politicians and other persons rely upon outdoor advertising because other forms of advertising are insufficient, inappropriate and prohibitively expensive.” Joint Stipulation of Facts No. 28, App. 48a.
Nor is there any evidence that the total elimination of the outdoor advertising business will have any economic effect on manufacturers of onsite signs. See Justice Beennan’s opinion concurring in the judgment, ante, at 526, n. 5.
Appellants each own between 500 and 800 outdoor advertising displays in San Diego. See Joint Stipulation of Facts No. 13, App. 44a. All of their signs are located in areas zoned for commercial and industrial uses. Joint Stipulation of Facts No. 20, App. 45a.
The California Supreme Court’s narrowing construction of the ordinance was specifically intended to exclude from the coverage of the ordinance signs very different from commercial billboards, such as “a picket sign announcing a labor dispute or a small sign placed in one’s front yard proclaiming a political or religious message.” 26 Cal. 3d, at 856, n. 2, 610 P. 2d, at 410, n. 2.
See, e. g., McGowan v. Maryland, 366 U. S. 420, 429: “[T]he general rule is that 'a litigant may only assert his own constitutional rights or immunities’ . . . .”
See, e. g., DombrowsH v. Pfister, 380 U. S. 479; Gooding v. Wilson, 405 U. S. 518; Keyishian v. Board of Regents, 385 U. S. 589; Shuttles-worth v. Birmingham, 394 U. S. 147.
Even the dissenting Justices in Broadrick, although they disagreed with the Court's refusal to apply the overbreadth doctrine in that case, acknowledged that an overbreadth challenge should not be entertained in every case raising First Amendment issues:
“We have never held that a statute should be held invalid on its face merely because it is possible to conceive of a single impermissible applica*548tion, and in that sense a requirement of substantial o-verbreadth is already implicit in the doctrine.” 413 U. S., at 630 (BreNNAN, J., joined by Stewart and Marshall, JJ., dissenting).
Indeed, the parties stipulated that onsite advertising differs in significant respects from the outdoor advertising business in which appellants are engaged. See n. 5, supra.
Ironically, today the plurality invalidates this ordinance — not because it is too broad — but rather because it is not broad enough. It assumes for the purpose of decision that a repeal of all exceptions, including the exception for onsite advertising, would cure the defects it finds in the present ordinance. See ante, at 515, n. 20. However, because neither the appellants nor the onsite advertisers would derive any benefits from a repeal of the exception for onsite commercial signs, the plurality’s reliance on the overbreadth doctrine to support vicarious standing in this case is curious indeed.
Compare Chicago Board of Trade v. United States, 246 U. S. 231, with United States v. Trenton Potteries Co., 273 U. S. 392.
Because the record mates it clear that the business of operating billboards has prospered in San Diego, it is obvious that this medium is more effective than others for some forms of communication. See n. 8, supra.
See nn. 8, 9, supra. '
See generally A. Read, Classic American Graffiti (1977); R. Reisner, Graffiti: Two Thousand Years of Wall Writing (1971); V. Pritchard, English Medieval Graffiti (1967).
In his opinion announcing the judgment of the Court, Justice Reed wrote:
“That more people may be more easily and cheaply reached by sound trucks, perhaps borrowed without cost from some zealous supporter, is not enough to call forth constitutional protection for what those charged with public welfare reasonably think is a nuisance when easy means of publicity are open.” 336 U. S., at 88-89.
That excerpt from Justice Black’s dissent is not, of course, sufficient evidence to tell us whether or not he would have upheld a city’s total ban on billboards. It does seem clear, however, that he did not adopt the absolute position that any reduction in the quantity of effective communication is categorically prohibited by the First Amendment. The full paragraph in which the quoted phrase appears reads:
“I am aware that the 'blare’ of this new method of carrying ideas is susceptible of abuse and may under certain circumstances constitute an *551intolerable nuisance. But ordinances can be drawn which adequately protect a community from unreasonable use of public speaking devices without absolutely denying to the community’s citizens all information that may be disseminated or received through this new avenue for trade in ideas. I would agree without reservation to the sentiment that ‘unrestrained use throughout a municipality of all sound amplifying devices would be intolerable.’ And of course cities may restrict or absolutely ban the use of amplifiers on busy streets in the business area. A city ordinance that reasonably restricts the volume of sound, or the hours during which an amplifier may be used, does not, in my mind, infringe the constitutionally protected area of free speech. It is because this ordinance does none of these things, but is instead an absolute prohibition of all uses of an amplifier on any of the streets of Trenton at any time that I must dissent.” Id., at 104.
Our decisions invalidating ordinances prohibiting or regulating door-to-door solicitation and leafletting are not to the contrary. In those cases, the state interests the ordinances purported to serve — for instance, the prevention of littering or fraud — were only indirectly furthered by the regulation of communicative activity. See, e. g., Schneider v. State, 308 U. S. 147, 162, 164; Martin v. City of Struthers, 319 U. S. 141, 147-148; Cantwell v. Connecticut, 310 U. S. 296, 306; Schaumburg v. Citizens for a Better Environment, 444 U. S. 620, 636-639. In many of the cases, the ordinances provided for a licensing scheme, rather than a blanket prohibition. The discretion thus placed in the hands of municipal officials was found constitutionally offensive because of the risk of censorship. See, e. g., Schneider, supra, at 163-164; Hague v. CIO, 307 U. S. 496, 516 (opinion of Roberts, J.); Lovell v. Griffin, 303 U. S. 444, 451-452; Cantwell, supra, at 305-307. In addition, because many of these cases involved the solicitation efforts of the Jehovah’s Witnesses, see, e. g., Lovell, supra, at 448; Jamison v. Texas, 318 U. S. 413, 413-414; Schneider, supra, at 158; Martin, supra, at 142; Cantwell, supra, at 300, the Court was properly sensitive to the risk that the ordinances could be used to suppress unpopular viewpoints.
In this case, as the plurality acknowledges, the ban on billboards directly serves, and indeed is necessary to further, the city’s legitimate interests in traffic safety and aesthetics. See ante, at 507-510, 511. San Diego’s ordinance places no discretion in any municipal officials, and there is no *552reason to suspect that the ordinance was designed or is being applied to suppress unpopular viewpoints.
It seems fair to infer that Justice Douglas, who cast the deciding vote in Lehman v. City of Shaker Heights, 418 U. S. 298, would have approved of a prohibition on billboards. See his opinion concurring in the judgment, id., at 306-308. After drawing an analogy between billboards and advertising on municipal vehicles, Justice Douglas noted:
“In my view the right of the commuters to be free from forced intrusions on their privacy precludes the city from transforming its vehicles of public transportation into forums for the dissemination of ideas upon this captive audience.” Id., at 307.
Most of the ordinance’s 12 exceptions, quoted ante, at 495, n. 3 (opinion of White, J.), are not based on the subject matter of speech. Several exceptions can be disregarded because they pertain to signs that are not within the coverage of the ordinance at any rate, in light of the California Supreme Court’s limiting construction. See n. 3, supra. The exceptions relating to vehicular signs fall into this category, see §§ 101.0700 (F)(9), (10), as do the exceptions for signs in transit and storage, see § 101.0700 (F) (3), and for temporary subdivision directional signs, see § 101.0700 (F) (11). The exception for “for sale” signs also appears to describe signs not covered by the ordinance since such signs ordinarily are not “permanently affixed to the ground or permanently attached to a building.” Of the remaining exceptions, two are based on the location, rather than content, of the signs, see §§ 101.0700 (F) (2), (6), and a third permits signs required by law or otherwise erected in discharge of governmental functions, see § 101.0700 (F) (1). Thus, only four exceptions are actually based in any way on the subject matter of the signs at issue. See §§ 101.0700 (F)(4), (5), (8), (12).