In ''American Trucking Ass'ns v. Scheiner'', 483 U.S. 266 (1987), the [[U.S. Supreme Court]] struck down two "flat" taxes imposed by Pennsylvania as preconditions to the use of the State's roads by commercial motor vehicles--a "marker fee" and an "axle tax," neither of which varied in amount depending on the number of miles that a particular vehicle traveled within the State.<ref>''See id.'' at 273-274.</ref>
The Court offered two bases for its invalidation of the taxes:
:First, the Court found that the challenged flat taxes discriminated against out-of-state businesses.
:Second, the Court in Scheiner also held<ref>483 U.S. at 284-285.</ref> that the challenged flat taxes violated the "internal consistency" prong of the "fair apportionment" requirement that the Court has applied to state taxes levied on interstate commercial activity. The Scheiner Court explained that, "if each State imposed flat taxes for the privilege of making commercial entrances into its territory, there is no conceivable doubt that commerce among the States would be deterred."<ref>483 U.S. at 284.</ref> Scheiner's discussion of internal consistency was closely linked to its determination that the Pennsylvania flat taxes discriminated against out-of-state carriers.<ref>''See id.'' at 285-286.</ref>
The Court's reference to the possible cumulative impacts of multiple flat taxes, however, suggests the related but distinct concern that a proliferation of such taxes would impose increasing burdens on vehicles operating in a large number of States, thus impeding the ability of interstate carriers to engage in unfettered "travel within the free trade area" established by the Commerce Clause.<ref>''Id.'' at 284; ''see id.'' at 285 nn.19 & 20.</ref>
== References ==
[[category:United States Supreme Court Cases]]