Mr. Justice Minton
delivered the opinion of the Court.
Appellants, American citizens, are taxicab drivers. They were arrested by the Sheriff of San Diego County, California, and charged with driving taxicabs in the unincorporated area of San Diego County without a permit from the Sheriff as required by § 9 of Ordinance 464, the pertinent provisions of which are set forth in the margin. The facts were stipulated without the taking of any evidence. From the stipulation we learn that appellants had picked up passengers across the line in Mexico and were transporting them across the unincorporated area of San Diego County to points not in the unincorporated area when they were arrested. They had made oral requests for permits from the Sheriff, rather than application in writing on the forms provided therefor, as required by § 9 of the ordinance. When these requests were denied, they continued to transport passengers, although upon advice of counsel they did not pick up or discharge any passengers in the unincorporated area. We take their action to mean that they claimed that because they were engaged in foreign commerce, they had either the right to a permit without complying with the other provisions of the ordinance or the right to operate without a permit. Appellants contend that the County had no right to burden that foreign commerce by regulation.
They were found guilty of violating § 9 of the ordinance by the Justice’s Court of National Township, San Diego County. The Superior Court of California, in and for the County of San Diego, Appellate Department, affirmed the conviction and allowed an appeal to this Court. 101 Cal. App. 2d Supp. 912, 226 P. 2d 87. We noted probable jurisdiction under 28 U. S. C. § 1257 (2).
The Motor Carrier Act of 1935 gave broad power of regulation over motor vehicles to the Interstate Commerce Commission; but Congress partially excluded taxicabs from such regulation in the following words:
“Nothing in this part, except the provisions of section 204 relative to qualifications and maximum hours of service of employees and safety of operation or standards of equipment shall be construed to include ... (2) taxicabs, or other motor vehicles performing a bona fide taxicab service, having a capacity of not more than six passengers and not operated on a regular route or between fixed termini . . . .” 49 Stat. 545, 49 U. S. C. § 303 (b).
The Interstate Commerce Commission, acting under authorization of Congress, has promulgated regulations establishing minimum qualifications for drivers of motor vehicles for carriers, including taxicabs, engaged in interstate and foreign commerce, 49 CFR § 192.2. This does not prevent the state or a subdivision thereof, in the exercise of its police power, from providing additional specifications as to qualifications, not inconsistent or in conflict with the regulations of the Interstate Commerce Commission. Especially is this true since the regulations of the Commission are only minimum.
As the ordinance is not in conflict with and may be construed consistently with the federal regulations and in keeping with the latter’s purpose, they may stand together. Kelly v. Washington, 302 U. S. 1, 10; Missouri, K. & T. R. Co. v. Harris, 234 U. S. 412, 419; Savage v. Jones, 225 U. S. 501, 539; Reid v. Colorado, 187 U. S. 137, 148.
California has a legitimate interest in the kind and character of persons who engage in the taxicab business in the State. The authority to issue permits has been granted by the State to the Board of Supervisors of each county. In re Martinez, 22 Cal. 2d 259, 262, 138 P. 2d 10. Such delegation by the State to the county has been approved by this Court. Sprout v. South Bend, 277 U. S. 163, 171, 172.
The operation of taxicabs is a local business. For that reason, Congress has left the field largely to the states. Operation of taxiqabs across state lines or international boundaries is so closely related to the local situation that the regulation of all taxicabs operating in the community only indirectly affects those in commerce, and so long as there is no attempt to discriminatorily regulate or directly burden or charge for the privilege of doing business in interstate or foreign commerce, the regulation is valid. The operation is “essentially local,” and in the absence of federal regulation, state regulation is required in the public interest. Panhandle Pipe Line Co. v. Michigan Pub. Serv. Comm’n, 341 U. S. 329, 333. Even if appellants were engaged in foreign commerce at the time of their arrest and did not intend to engage in intrastate commerce, the permit was not required because they were engaged in foreign commerce. Under the permit they were free to engage in both intrastate and foreign commerce. The ordinance requires a written application for a permit, a small fee, and compliance with certain standards relating to the service and to the public safety. Our prior cases would not justify us in holding that the ordinance is an unreasonable burden on foreign commerce in its application to the stipulated facts here. Aero Transit Co. v. Georgia Comm’n, 295 U. S. 285; Hicklin v. Coney, 290 U. S. 169; cf. Railway Express Agency v. New York, 336 U. S. 106, 111.
Thus far we have dealt only with § 9 of the ordinance, which exacts the $1 fee for a driver’s permit. That is all the court we are reviewing passed upon. That is all appellants were tried and convicted for. But it is suggested that the permit may have been denied them because they had violated § 4 of the ordinance by not getting a taxicab operator’s license and paying the $50 fee therefor. But appellants may also have been denied permits under § 9 for the reason that oral requests only were made and not written applications to the Sheriff, as required by the ordinance, or the Sheriff may have found them without knowledge as to the geography of the county and traffic regulations, or that they were persons of bad moral character or had been convicted of a crime involving moral turpitude, all adequate state grounds. In that event, this Court would not take jurisdiction to pass upon the question. Chief Justice Hughes, speaking for the Court in Lynch v. New York ex rel. Pierson, 293 U. S. 52, 54-55, said:
“[I]f it does not appear upon which of two grounds the judgment was based, and the ground independent of a federal question is sufficient in itself to sustain it, this Court will not take jurisdiction.” (Citing numerous cases.)
This Court should not be reaching for constitutional questions to cast doubt upon state legislation not before the Court. The constitutional validity of the $50 requirement is not now before the Court and was not before the lower court.
The judgment of the Superior Court of California is
Affirmed.
“Applicants for such permits shall file applications therefor with the sheriff of the County of San Diego on a form furnished by the sheriff which, when completed, will contain full personal information concerning the applicant.
“Upon obtaining a permit as herein required the holder of such permit shall be entitled to an identification card of such design, and bearing such number as the sheriff may prescribe, upon payment of a fee of $1.00 annually, therefor, which shall be paid by the applicant to the tax collector and shall be due on the 1st day of June of each year. Such card shall be carried by the permittee during all business hours and shall not be transferable.
“Each applicant for a permit shall be examined by the sheriff as to his knowledge of the provisions of this ordinance, the Vehicle Code, traffic regulations and the geography of the county, and if the result of the examination is unsatisfactory he shall be refused a permit. The sheriff may deny the application or having issued the permit may revoke the same if the sheriff shall determine that the applicant or taxicab driver is of bad moral character or is guilty of violation of any of the provisions of this ordinance or of any lawful regulation promulgated pursuant thereto or has been convicted of any offense involving moral turpitude.”