delivered the opinion of the Court.
Thе Ohio Motor Transportation Act of 1923, as amended, Gen. Code, §§ 614-84 to 614-102, provides that a motor transportation сompany desiring to operate within the State shall'apply to the Public Utilities Commission for a certificate so to do and shall not begin to operate without first obtaining it; also, that such a company must pay, at the time of the issuance of the certificate and annually thereafter, a tax graduated according *556 to the number and capacity of the vehicles used. §§ 614-87, 614-94.
Clark and Riggs operate as common carriers a motor truck line betwеen Aurora, Indiana, and Cincinnati, Ohio, exclusively in interstate commerce. They ignored 'the provisions of-the Act, аnd operated without applying for a certificate or paying the tax. Then they brought this suit, in the federal court for southern Ohio, to enjoin the Commission from enforcing as against them ‘the provisions of the Act. The case was heаrd in the District Court before three judges on final hearing, under § 266 of the Judicial Code as amended by the Act of February 13, 1925. It aрpeared that while the Act calls the certificate one of “ public convenience and necessity,” the Commission had recognized, before this suit was begun, that, under
Buck
v.
Kuykendall,
The plaintiffs clаim that, as applied to them, the Act violates the commerce elapse of the Federal Constitution. Thеy insist that, as they are engaged exclusively -in interstate commerce, they are not subject to regulation by the State; that it is without power to require that before using its highways they apply for and obtain a certificate; and that it is аlso without power to impose, in addition to the annual license fee demanded of all persons using automobiles on the highways, a tax upon them, under
*557
§ 614-94, for the maintenance and repair of the highways and for the administration аnd enforcement of the laws governing the use of the same. The contrary is settled. The highways are public proрerty. Users of them, although engaged exclusively in interstate commerce, are subject to regulation by the State to ensure safety and convenience and the conservation of the highways. Morris v.
Duby, ante,
p. 135;
Hess
v.
Pawloski, ante,
p. 352. Users of them, although engаged exclusively in interstate commerce, may be required to contribute to their cost and upkeep. Common carriers for hire, who make the highways their place of business, may properly be charged an extra tax for such use.
Hendrick
v.
Maryland,
There is no suggestion that the tax discriminates against interstate commerce. Nor is it suggested that the tax is so large as to obstruct interstate commerce. It is said that all of the tax is not used for maintenance and repаir of the highways; that some of it is used for defraying the expenses of the Commission in the administration or enforcement оf the Act; and some for other purposes. This, if true, is. immaterial. Since the tax is assessed for a proper purpose and is not objectionable in amount, the use to which the proceeds are put is not a matter which concerns the plaintiffs.
Plaintiffs urge that the decree should be reversed because of the provision in the Act сoncerning insurance. The Act provides that no certificate shall issue until a policy covering liability and cаrgo insurance has been filed with the Commission. § 614-99. The lower court held that, under
Michigan Public Utilities Commission
v.
Duke,
It is not clear whether the liability insurance, for which the Act provides, is against loss resulting to third рersons from the applicant’s negligence in using the highways within the State, or is for loss tq> passengers resulting from such negligenсe, or for both purposes. We have no occasion to consider whether, under any suggested interpretаtion, liability insurance, as distinguished from insurance on the interstate cargo, may be required of a carrier engagеd wholly in interstate commerce. Compare Hess v. Pawloski, supra. The decree dismissing the bill is affirmed, but without prejudice to the right of the plaintiffs tp seek appropriate relief by another suit if they should hereafter be required by the Commission to comply with conditions or provisions not warranted by law. Affirmed.
