highways in the State or to defray the expense of regulating motor
traffic.[747] Later decisions follow in the same general track,[748] the
most recent one being Capitol Greyhound Lines _v._ Brice,[749] in which
the Court, speaking by Justice Black passed upon a Maryland excise tax
on the fair market value of motor vehicles used in interstate commerce
as a condition to the issuance of certificates of title as prerequisites
to the registration and operation of motor vehicles in the State.
Because the tax was applied to vehicles used in both interstate and
intrastate commerce and the proceeds were used for road purposes and
because the Court considered the tax, though actually separate, to be an
adjunct of Maryland's mileage tax, it was able to find that the total
charge varied substantially with the mileage travelled, and on that
ground sustained it, being constant, it said with "rough approximation
rather than precision," no showing having been made that Maryland's
taxes considered as a whole exceeded "fair compensation for the
privilege of using State roads." Justice Frankfurter, who was joined by
Justice Jackson, dissented, and in so doing contributed as an Appendix
to his opinion a useful analysis of decisions involving State taxation
of motor vehicles engaged in interstate commerce, for highway
purposes.[750]

Public Utilities; Regulatory Charges

"The principles governing decision [in this class of cases] have
repeatedly been announced and were not questioned below.[751] In the
exercise of its police power the State may provide for the supervision
and regulation of public utilities, such as railroads; may delegate the
duty to an officer or commission; and may exact the reasonable cost of
such supervision and regulation from the utilities concerned and
allocate the exaction amongst the members of the affected class without
violating the rule of equality imposed by the Fourteenth Amendment.[752]
The supervision and regulation of the local structures and activities of
a corporation engaged in interstate commerce, and the imposition of the
reasonable expense thereof upon such corporation, is not a burden upon,
or regulation of, interstate commerce in violation of the commerce
clause of the Constitution.[753] A law exhibiting the intent to impose a
compensatory fee for such a legitimate purpose is _prima facie_
reasonable.[754] If the exaction be so unreasonable and disproportionate
to the service as to impugn the g