delivered the opinion of the Court.

This appeal brings to this Court the question of the constitutionality of an act of Virginia,1 which requires all passenger motor vehicle carriers, both interstate and intrastate,2 to separate without discrimination3 the white and colored passengers in their motor buses so that contiguous seats will not be occupied by persons of different races at the same time. A violation of the requirement of separation by the carrier is a misdemeanor.4 The driver or other person in charge is directed and required to increase or decrease the space allotted to the respective races as may be necessary or proper and may require passengers to change their seats to comply with the allocation. The operator’s failure to enforce the provisions is made a misdemeanor.5

These regulations were applied to an interstate passenger, this appellant, on a motor vehicle then making an interstate run or trip. According to the statement of fact by the Supreme Court of Appeals of Virginia, appellant, who is a Negro, was traveling on a motor common car*375rier, operating under the above-mentioned statute, from Gloucester County, Virginia, through the District of Columbia, to Baltimore, Maryland, the destination of the bus. There were other passengers, both white and colored. On her refusal to accede to a request of the driver to move to a back seat, which was partly occupied by other colored passengers, so as to permit the seat that she vacated to be used by white passengers, a warrant was obtained and appellant was arrested, tried and convicted of a violation of § 4097dd of the Virginia Code.6 On a writ of error the conviction was affirmed by the Supreme Court of Appeals of Virginia. 184 Va. 24. The Court of Appeals interpreted the Virginia statute as applicable to appellant since the statute “embraces all motor vehicles and all *376passengers, both interstate and intrastate.” 7 The Court of Appeals refused to accept appellant’s contention that the statute applied was invalid as a delegation of legislative power to the carrier by a concurrent holding “that no power is delegated to the carrier to legislate .... The statute itself condemns the defendant’s conduct as a violation of law and not the rule of the carrier.” Id., at 38. No complaint is made as to these interpretations of the Virginia statute by the Virginia court.8

The errors of the Court of Appeals that are assigned and relied upon by appellant are in form only two. The first is that the decision is repugnant to Clause 3, § 8, Article I of the Constitution of the United States,9 and the second the holding that powers reserved to the states by the Tenth Amendment include the power to require an interstate motor passenger to occupy a seat restricted for the use of his race. Actually, the first question alone needs consideration for, if the statute unlawfully burdens interstate commerce, the reserved powers of the state will not validate it.10

We think, as the Court of Appeals apparently did, that the appellant is a proper person to challenge the validity of this statute as a burden on commerce.11 If it is an invalid burden, the conviction under it would fail. The statute affects appellant as well as the transportation company. Constitutional protection against burdens on com*377merce is for her benefit on a criminal trial for violation of the challenged statute. Hatch v. Reardon, 204 U. S. 152, 160; Federation of Labor v. McAdory, 325 U. S. 450, 463.

This Court frequently must determine the validity of state statutes that are attacked as unconstitutional interferences with the national power over interstate commerce. This appeal presents that question as to a statute that compels racial segregation of interstate passengers in vehicles moving interstate.12

The precise degree of a permissible restriction on state power cannot be fixed generally or indeed not even for one kind of state legislation, such as taxation or health or safety.13 There is a recognized abstract principle, however, that may be taken as a postulate for testing whether particular state legislation in the absence of action by Congress is beyond state power. This is that the state legislation is invalid if it unduly burdens that commerce in matters where uniformity is necessary — necessary in the constitutional sense of useful in accomplishing a permitted purpose14 Where uniformity is essential for the functioning of commerce, a state may not interpose its local regulation.15 Too true it is that the principle lacks in precision. Although the quality of such a principle is abstract, its application to the facts of a situation created by the attempted enforcement of a statute brings about a specific determination as to whether or not the statute *378in question is a burden on commerce. Within the broad limits of the principle, the cases turn on their own facts.

In the field of transportation, there has been a series of decisions which hold that where Congress has not acted and although the state statute affects interstate commerce, a state may validly enact legislation which has predominantly only a local influence on the course of commerce.16 It is equally well settled that, even where Con*379gress has not acted, state legislation or a final court order is invalid which materially affects interstate commerce.17 *380Because the Constitution puts the ultimate power to regulate commerce in Congress, rather than the states, the degree of state legislation’s interference with that commerce may be weighed by federal courts to determine whether the burden makes the statute unconstitutional.18 The courts could not invalidate federal legislation for the same reason because Congress, within the limits of the Fifth Amendment, has authority to burden commerce if that seems to it a desirable means of accomplishing a permitted end.19

This statute is attacked on the ground that it imposes undue burdens on interstate commerce. It is said by the Court of Appeals to have been passed in the exercise of the state’s police power to avoid friction between the races. But this Court pointed out years ago “that a State cannot avoid the operation of this rule by simply invoking the convenient apologetics of the police power.” 20 Burdens upon commerce are those actions of a state which directly “impair the usefulness of its facilities for such traffic.” 21 That impairment, we think, may arise from other causes than costs or long delays. A burden may arise from a state statute which requires interstate passengers to order *381their movements on the vehicle in accordance with local rather than national requirements.

On appellant’s journey, this statute required that she sit in designated seats in Virginia.22 Changes in seat designation might be made “at any time” during the journey when “necessary or proper for the comfort and convenience of passengers.” This occurred in this instance. Upon such change of designation, the statute authorizes the operator of the vehicle to require, as he did here, “any passenger to change his or her seat as it may be necessary or proper.” 23 An interstate passenger must if necessary repeatedly shift seats while moving in Virginia to meet the seating requirements of the changing passenger group. On arrival at the District of Columbia line, the appellant would have had freedom to occupy any available seat and so to the end of her journey.

Interstate passengers traveling via motor buses between the north and south or the east and west may pass through Virginia on through lines in the day or in the night. The large buses approach the comfort of pullmans and have seats convenient for rest. On such interstate journeys the enforcement of the requirements for reseating would be disturbing.

Appellant’s argument, properly we think, includes facts bearing on interstate motor transportation beyond those immediately involved in this journey under the Virginia statutory regulations. To appraise the weight of the burden of the Virginia statute on interstate commerce, related statutes of other states are important to show whether there are cumulative effects which may make *382local regulation impracticable. Eighteen states, it appears, prohibit racial separation on public carriers.24 Ten require separation oh motor carriers.25 Of these, Alabama applies specifically to interstate passengers with an exception for interstate passengers with through tickets from states without laws on separation of passengers.26 The language of the other acts, like this Virginia statute before the Court of Appeals’ decision in this case, may be said to be susceptible to an interpretation that they do or do not apply to interstate passengers.

In states where separation of races is required in motor vehicles, a method of identification as white or colored must be employed. This may be done by definition. Any ascertainable Negro blood identifies a person as colored for purposes of separation in some states.27 In the other states which require the separation of the races in *383motor carriers, apparently no definition generally applicable or made for the purposes of the statute is given. Court definition or further legislative enactments would be required to clarify the line between the races. Obviously there may be changes by legislation in the definition.28

The interferences to interstate commerce which arise from state regulation of racial association on interstate vehicles has long been recognized. Such regulation hampers freedom of choice in selecting accommodations. The recent changes in transportation brought about by the coming of automobiles does not seem of great significance in the problem. People of all races travel today more extensively than in 1878 when this Court first passed upon state regulation of racial segregation in commerce. The factual situation set out in preceding paragraphs emphasizes the soundness of this Court’s early conclusion in Hall v. DeCuir, 95 U. S. 485.

The DeCuir case arose under a statute of Louisiana interpreted by the courts of that state and this Court to require public carriers “to give all persons travelling in that State, upon the public conveyances employed in such business, equal rights and privileges in all parts of the conveyance, without distinction or discrimination on account of race or color.” Page 487. Damages were awarded against Hall, the representative of the operator of a Mississippi river steamboat that traversed that river interstate from New Orleans to Vicksburg, for excluding in Louisiana the defendant in error, a colored person, from a cabin reserved for whites. This Court reversed for reasons well *384stated in the words of Mr. Chief Justice Waite.29 As our previous discussion demonstrates, the transportation diffi*385culties arising from a statute that requires commingling of the races, as in the DeCuir case, are increased by one that requires separation, as here.30 Other federal courts have looked upon racial separation statutes as applied to interstate passengers as burdens upon commerce.31

In weighing the factors that enter into our conclusion as to whether this statute so burdens interstate commerce or so infringes the requirements of national uniformity as to be invalid, we are mindful of the fact that conditions *386vary between northern or western states such as Maine or Montana, with practically no colored population; industrial states such as Illinois, Ohio, New Jersey and Pennsylvania with a small, although appreciable, percentage of colored citizens; and the states of the deep south with percentages of from twenty-five to nearly fifty per cent colored, all with varying densities of the white and colored races in certain localities. Local efforts to promote amicable relations in difficult areas by legislative segregation in interstate transportation emerge from the latter racial distribution. As no state law can reach beyond its own border nor bar transportation of passengers across its boundaries, diverse seating requirements for the races in interstate journeys result. As there is no federal act dealing with the separation of races in interstate transportation, we must decide the validity of this Virginia statute on the challenge that it interferes with commerce, as a matter of balance between the exercise of the local police power and the need for national uniformity in the regulations for interstate travel. It seems clear to us that seating arrangements for the different races in interstate motor travel require a single, uniform rule to promote and protect national travel. Consequently, we hold the Virginia statute in controversy invalid.

Reversed.

concurring.

The Commerce Clause of the Constitution provides that “Congress shall have power ... to regulate commerce . . . among the several States." I have believed, and still believe, that this provision means that Congress *387can regulate commerce and that the courts cannot. But in a series of cases decided in recent years this Court over my protest has held that the Commerce Clause justifies this Court in nullifying state legislation which this Court concludes imposes an “undue burden” on interstate commerce.1 I think that whether state legislation imposes an “undue burden” on interstate commerce raises pure questions of policy, which the Constitution intended should be resolved by the Congress.

Very recently a majority of this Court reasserted its power to invalidate state laws on the ground that such legislation put an undue burden on commerce. Nippert v. Richmond, supra; Southern Pacific Co. v. Arizona, supra. I thought then, and still believe, that in these cases the Court was assuming the role of a “super-legislature” in determining matters of governmental policy. Id., at 788, n. 4.

But the Court, at least for the present, seems committed to this interpretation of the Commerce Clause. In the Southern Pacific Company case, the Court, as I understand its opinion, found an “undue burden” because a State’s requirement for shorter trains increased the cost of railroad operations and thereby delayed interstate commerce and impaired its efficiency. In the Nippert case a small tax imposed on a sales solicitor employed by concerns located outside of Virginia was found to be an “undue burden” even though a solicitor for Virginia concerns engaged in the same business would have been required to pay the same tax.

So long as the Court remains committed to the “undue burden on commerce formula,” I must make decisions under it. The “burden on commerce” imposed by the *388Virginia law here under consideration seems to me to be of a far more serious nature than those of the Nippert or Southern Pacific Company cases. The Southern Pacific Company opinion, moreover, relied in part on the rule announced in Hall v. DeCuir, 95 U. S. 485, which case held that the Commerce Clause prohibits a state from passing laws which require that “on one side of a State line . . . passengers, both white and colored, must be permitted to occupy the same cabin, and on the other be kept separate.” The Court further said that “uniformity in the regulations by which ... [a carrier] is to be governed from one end to the other of his route is a necessity in his business” and that it was the responsibility of Congress, not the states, to determine “what such regulations shall be.” The “undue burden on commerce formula” consequently requires the majority’s decision. In view of the Court’s present disposition to apply that formula, I acquiesce.

concurring.

My brother Burton has stated with great force reasons for not invalidating the Virginia statute. But for me Hall v. DeCuir, 95 U. S. 485, is controlling. Since it was decided nearly seventy years ago, that case on several occasions has been approvingly cited and has never been questioned. Chiefly for this reason I concur in the opinion of the Court.

The imposition upon national systems of transportation of a crazy-quilt of State laws would operate to burden commerce unreasonably, whether such contradictory and confusing State laws concern racial commingling or racial segregation. This does not imply the necessity for a nationally uniform regulation of arrangements for passengers on interstate carriers. Unlike other powers of Congress (see Art. I, § 8, cl. 1, concerning “Duties, Imposts *389and Excises”; Art. I, § 8, cl. 4, concerning “Naturalization”; Art. I, § 8, cl. 4, concerning “Bankruptcies”), the power to regulate commerce does not require geographic uniformity. Congress may devise a national policy with due regard to varying interests of different regions. E. g., 37 Stat. 699, 27 U. S. C. § 122; Clark Distilling Co. v. Western Maryland R. Co., 242 U. S. 311; 45 Stat. 1084, 49 U. S. C. § 60; Whitfield v. Ohio, 297 U. S. 431. The States cannot impose diversity of treatment when such diverse treatment would result in unreasonable burdens on commerce. But Congress may effectively exercise its power under the Commerce Clause without the necessity of a blanket rule for the country.

dissenting.

On the application of the interstate commerce clause of the Federal Constitution to this case, I find myself obliged to differ from the majority of the Court. I would sustain the Virginia statute against that clause. The issue is neither the desirability of the statute nor the constitutionality of racial segregation as such. The opinion of the Court does not claim that the Virginia statute, regulating seating arrangements for interstate passengers in motor vehicles, violates the Fourteenth Amendment or is in conflict with a federal statute. The Court holds this statute unconstitutional for but one reason. It holds that the burden imposed by the statute upon the nation’s interest in interstate commerce so greatly outweighs the contribution made by the statute to the State’s interest in its public welfare as to make it unconstitutional.

The undue burden upon interstate commerce thus relied upon by the Court is not complained of by the Federal Government, by any state, or by any carrier. This statute has been in effect since 1930. The carrier concerned is operating under regulations of its own which conform *390to the statute. The statute conforms to the policy adopted by Virginia as to steamboats (1900), electric or street cars and railroads (1902-1904) ,1 Its validity has been unanimously upheld by the Supreme Court of Appeals of Virginia. The argument relied upon by the majority of this Court to establish the undue burden of this statute on interstate commerce is the lack of uniformity between its provisions and those of the laws of other states on the subject of the racial separation of interstate passengers on motor vehicles.

If the mere diversity between the Virginia statute and comparable statutes of other states is so serious as to render the Virginia statute invalid, it probably means that the comparable statutes of those other states, being diverse from it and from each other, are equally invalid. This is especially true under that assumption of the majority which disregards sectional interstate travel between neighboring states having similar laws, to hold “that seating arrangements for the different races in interstate motor travel require a single, uniform rule to promote and protect national travel.” (Italics supplied.) More specifically, the opinion of the Court indicates that the laws of the 10 contiguous states of Virginia, North Carolina, South Carolina, Georgia, Alabama, Mississippi, Louisiana, Arkansas, Texas and Oklahoma require racial separation of passengers on motor carriers, while those of 18 other states prohibit racial separation of passengers on public carriers. On the precedent of this case, the laws of the 10 states requiring racial separation apparently can be invalidated because of their sharp diversity from the laws in the rest of the Union, or, in a lesser degree, because of their diversity from one another: Such invalidation, on the ground *391of lack of nation-wide uniformity, may lead to questioning the validity of the laws of the 18 states now prohibiting racial separation of passengers, for those laws likewise differ sharply from laws on the same subject in other parts of the Union and, in a lesser degree, from one another. In the absence of federal law, this may eliminate state regulation of racial separation in the seating of interstate passengers on motor vehicles and leave the regulation of the subject to the respective carriers.

The present decision will lead to the questioning of the validity of statutory regulation of the seating of intrastate passengers in the same motor vehicles with interstate passengers. The decision may also result in increased lack of uniformity between regulations as to seating arrangements on motor vehicles limited to intrastate passengers in a given state and those on motor vehicles engaged in interstate business in the same state or on connecting routes.

The basic weakness in the appellant’s case is the lack of facts and findings essential to demonstrate the existence of such a serious and major burden upon the national interest in interstate commerce as to outweigh whatever state or local benefits are attributable to the statute and which would be lost by its invalidation. The Court recognizes that it serves as “the final arbiter of the competing demands of state and national interests” 2 and that it must fairly determine, in the absence of congressional action, whether the state statute actually imposes such an undue burden upon interstate commerce as to invalidate that statute. In weighing these competing demands, if this Court is to justify the invalidation of this statute, it must, first of all, be satisfied that the many years of experience of the state and the carrier that are reflected in this *392state law should be set aside. It represents the tested public policy of Virginia regularly enacted, long maintained and currently observed. The officially declared state interests, even when affecting interstate commerce, should not be laid aside summarily by this Court in the absence of congressional action. It is only Congress that can supply affirmative national uniformity of action.

In Southern Pacific Co. v. Arizona, 325 U. S. 761, 768-769, 770, this Court speaking through the late Chief Justice said:

“In the application of these principles some enactments may be found to be plainly within and others plainly without state power. But between these extremes lies the infinite variety of cases, in which regulation of local matters may also operate as a regulation of commerce, in which reconciliation of the conflicting claims of state and national power is to be attained only by some appraisal and accommodation of the competing demands of the state and national interests involved.3

“But in general Congress has left it to the courts to formulate the rules thus interpreting the commerce clause in its application, doubtless because it has appreciated the destructive consequences to the commerce of the nation if their [i. e. the courts’] protection were withdrawn, . . . and has been aware that in their application state laws will not be invalidated without the support of relevant factual material which will ‘afford a sure basis’ for an informed judgment.4 . . . Meanwhile, Congress has accommodated its legislation, as have the states, to these rules as an established feature of our constitutional system. There has thus been left to the states wide scope for *393the regulation of matters of local state concern, even though it in some measure affects the commerce, provided it does not materially restrict the free flow of commerce acro'ss state lines, or interfere with it in matters with respect to which uniformity of regulation is of predominant national concern.” (Italics supplied.)

The above-quoted requirement of a factual establishment of “a sure basis” for an informed judgment by this Court calls for a firm and demonstrable basis of action on the part of this Court. In the record of this case there are no findings of fact that demonstrate adequately the excessiveness of the burden, if any, which the Virginia statute has imposed upon interstate commerce, during the many years since its enactment, in comparison with the resulting effect in Virginia of the invalidation of this statute.5 The Court relies largely upon the recital of a nation-wide diversity among state statutes on this subject without a demonstration of the factual situation in those states, and especially in Virginia. The Court therefore is not able in this case to make that necessary “appraisal and accommodation of the competing demands of the state and national interests involved” which should be the foundation for passing upon the validity of a state statute of long standing and of important local significance in the exercise of the state police power.

*394The Court makes its own further assumption that the question of racial separation of interstate passengers in motor vehicle carriers requires national uniformity of treatment rather than diversity of treatment at this time. The inaction of Congress is an important indication that, in the opinion of Congress, this issue is better met without nationally uniform affirmative regulation than with it. Legislation raising the issue long has been, and is now, pending before Congress but has not reached the floor of either House.6 The fact that 18 states have prohibited in some degree racial separation in public carriers is important progress in the direction of uniformity. The fact, however, that 10 contiguous states in some degree require, by state law, some racial separation of passengers on motor carriers indicates a different appraisal by them of the needs and conditions in those areas than in others. The remaining 20 states have not gone equally far in either direction. This recital of existing legislative diversity is evidence against the validity of the assumption by this Court that there exists today a requirement of a single uniform national rule on the subject.

It is a fundamental concept of our Constitution that where conditions are diverse the solution of problems arising out of them may well come through the application of diversified treatment matching the diversified needs as determined by our local governments. Uniformity of treatment is appropriate where a substantial uniformity of conditions exists.