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. It is equally well settled that, even where Congress has not acted, state legislation or a final court order is invalid which materially affects interstate commerce. Because 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. 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.
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." Burdens upon commerce are those actions of a state which directly "impair the usefulness of its facilities for such traffic." 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 their 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. 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." 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. . . .
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 local regulation impracticable. Eighteen states, it appears, prohibit racial separation on public carriers. Ten require separation on motor carriers. . . .
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. . . .
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