Mr. Justice Blackmun
delivered the opinion of the Court.
United Air Lines, Inc., challenged the constitutionality of the Illinois general revenue use tax as applied to aviation fuel stored in Illinois and then loaded aboard aircraft there and consumed in interstate flights. The Supreme Court of Illinois upheld the state tax as currently applied, concluding that it did not impose an unconstitutional burden on interstate commerce. 49 Ill. 2d 45, 273 N. E. 2d 585 (1971). We noted probable jurisdiction. 405 U. S. 986 (1972). We now affirm that holding, but we vacate the judgment and remand the case for consideration of an issue under state law.
Since 1953, United has purchased aviation fuel from a supplier for delivery from the supplier’s Indiana facilities. This fuel is utilized by United in its extensive operations out of O’Hare and Midway airports in the Chicago area of Illinois. Although the method of delivery varies for different types of fuel and for the two airports, all fuel is delivered by common carrier and is held for periods ranging from two to 12 days in ground storage facilities maintained in Illinois by United. Fuel for both interstate and intrastate operations is delivered in the same manner. United voluntarily has paid the tax on fuel consumed in purely intrastate operations. Only the tax as applied to fuel used in interstate flights is in issue.
In 1955, Illinois enacted a general tax on the “privilege of using” tangible personal property in the State. Ill. Rev. Stat., c. 120, § 439.3 (1971). “Use” was defined to include the “exercise ... of any right or power over tangible personal property incident to the ownership of that property.” § 439.2. Some exceptions from this inclusive definition were made. One of these exceptions, which the statute recites, § 439.3, is “[t]o prevent actual or likely multistate taxation,” is the temporary-storage provision. This denies application of the tax to property brought from another State and stored temporarily in Illinois before use solely outside the State.
Since this general use tax, apart from its exceptions, reached all tangible personal property, it applied by its terms to fuel stored for use in vehicles. From 1955 to 1963, the Illinois Department of Revenue allowed interstate common carriers to benefit from the temporary-storage provision to the extent that fuel, although loaded aboard in Illinois, was not consumed by the vehicle in that State. The amount of aviation fuel used over Illinois could be calculated because scheduled airline routes are precise and the rate of consumption by each type of aircraft is known. This “burn off” interpretation was changed in 1963, however, when the Department announced by bulletin that it was reinterpreting the temporary-storage provision to mean that “temporary storage ends and a taxable use occurs when the fuel is taken out of storage facilities and is placed into the tank of the airplane, railroad engine or truck.” Thus, as the Illinois court described it, “all fuel loaded on United’s planes at the two airports was deemed to measure the tax.” 49 Ill. 2d, at 49, 273 N. E. 2d, at 587.
United’s suit attacked the new interpretation on both state and federal grounds. All justices of the Supreme Court of Illinois agreed that the new interpretation did not run afoul of the Federal Constitution, but the justices disagreed over the applicability and validity of the “burn off” alternative discussed in the several opinions. 49 Ill. 2d, at 50-53, 56, 57-59, 273 N. E. 2d, at 587-589, 591-592.
I
Two decisions of this Court were relied upon by the Illinois court in reaching its conclusion that the present application of the state tax was not offensive to the Federal Constitution. The cases are Edelman v. Boeing Air Transport, 289 U. S. 249 (1933), and Nashville, Chattanooga & St. Louis R. Co. v. Wallace, 288 U. S. 249 (1933). We agree that these cases support the application of the Illinois tax to all fuel stored in Illinois and loaded aboard United’s aircraft for in-flight consumption.
In Edelman, this Court upheld a state gasoline use tax, even when imposed on gasoline imported from outside the State, stored in tanks at an airport, and loaded aboard planes departing on interstate flights. The decision in Edelman followed the holding in Nashville that oil purchased by a railroad outside Tennessee but stored in Tennessee solely for the purpose of providing motive power for the railroad’s interstate and intrastate operations could be subjected constitutionally to a Tennessee privilege tax. In Nashville, as in this case, none of the fuel stored was held as inventory for sale, and the tax was not one for the use of special services furnished by the State to the taxpayer railroad.
In Edelman, the Court accepted the State’s determination that the taxable event was withdrawal from storage rather than consumption. 289 U. S., at 251. The airline in Edelman contended, id., at 252, that the state tax was invalid under Helson v. Kentucky, 279 U. S. 245 (1929). In Helson, the Court held that a Kentucky tax on the use of gasoline within the State fell too directly on interstate commerce when it was imposed on fuel loaded in Illinois but consumed in the course of an interstate ferry’s trip through Kentucky. In Edelman, the Court distinguished Helson because storage, rather than consumption, was the taxable event. See Southern Pacific Co. v. Gallagher, 306 U. S. 167 (1939).
The Supreme Court of Illinois characterized the taxable “use” under the Illinois statute as either storage or withdrawal from storage. United argued in the state court that the temporary-storage provision constituted a legislative waiver of the right to tax storage prior to loading. The Illinois court rejected this contention, noting that United stored fuel at the airport for general use. On these facts, the Supreme Court of Illinois concluded that the Illinois use tax applied to storage by United before loading and that this application was constitutional:
“Under the circumstances, the 'storage’ becomes something more than a 'temporary storage’ for safekeeping prior to its use solely outside of Illinois. Such storage, under the plain words of the statute, does not qualify under the temporary storage exemption and, as the authorities already discussed reveal, either the storage itself or the withdrawal therefrom are uses which may be taxed without offending the commerce clause of the Federal constitution.” 49 Ill. 2d, at 55-56, 273 N. E. 2d, at 590 (emphasis added).
The Illinois dissenters, too, treated the taxable event as storage or withdrawal. 49 Ill. 2d, at 57, 273 N. E. 2d, at 591.
This Court usually has deferred to the interpretation placed on a state tax statute by the highest court of the State. Scripto, Inc. v. Carson, 362 U. S. 207, 210 (1960); General Trading Co. v. State Tax Comm’n, 322 U. S. 335, 337 (1944). See Evco v. Jones, 409 U. S. 91 (1972). As in Edelman, we see no reason to ignore, or to disagree with, the state court’s determination that the taxable event is storage rather than consumption.
We hold that Edelman and Nashville support the conclusion of the Supreme Court of Illinois that this tax, as applied to all fuel withdrawn from storage for consumption in an interstate vehicle, does not place an unconstitutional burden on interstate commerce. Further, we decline to hold that Edelman has outlived its usefulness. We must concede that for a long time this area of state tax law has been cloudy and complicated, primarily because the varied nature of interstate activities makes line drawing difficult. This Court has established some precedents, however, and Edelman and Nashville remain useful guidelines.
The line drawn between an impermissible tax on mere consumption of fuel, as in Helson, and a permissible tax on storage of fuel before loading, as in Edelman and Nashville, continues to serve rational purposes. Retaining the line at this point minimizes the danger of double taxation and yet provides a source of revenue having a relation to the event taxed. Double taxation is minimized because the fuel cannot be taxed by States through which it is transported, under Michigan-Wiscousin Pipe Line Co. v. Calvert, 347 U. S. 157 (1954), nor by the State in which it is merely consumed, under Helson. A fair result is achieved because a State in which preload-ing storage facilities are maintained is likely to provide substantial services to those facilities, including police protection and the maintenance of public access roads.
Since no persuasive reason has been advanced for changing the established rule, we reaffirm Edelman and Nashville as precedents.
II
United contended in state court that the Illinois temporary-storage exemption should be interpreted, as a matter of state law, to encompass the “burn off” rule which, as noted above, had received administrative sanction for eight years. 49 Ill. 2d, at 49, 273 N. E. 2d, at 587. Two justices of the Illinois court deemed themselves bound under Helson to regard the “burn off” rule as invalid under the Federal Constitution. 49 Ill. 2d, at 50, 273 N. E. 2d, at 587. This basis for construing a state statute creates a federal question. Red Cross Line v. Atlantic Fruit Co., 264 U. S. 109, 120 (1924). The possibility that the state court might have reached the same conclusion if it had decided the question purely as a matter of state law does not create an adequate and independent state ground that relieves this Court of the necessity of considering the federal question. Beecher v. Alabama, 389 U. S. 35, 37 n. 3 (1967); see C. Wright, Federal Courts § 107, p. 488 (2d ed. 1970). Since the other justices of the Illinois court divided three to two on the state law issue, the votes of the two who felt bound by Helson could be determinative of the state issue. Under these circumstances, we proceed to consider the validity of the “burn off” rule in the light of Helson, as United has urged us to do. See Perkins v. Benguet Mining Co., 342 U. S. 437, 441-443 (1952).
The facts in Helson are different from the facts here. In Helson, the operators of the interstate ferry boat purchased and took delivery of fuel in Illinois. The office, the place of business, and the situs of all the taxpayer’s property were in Illinois. The boat crossed the Ohio River into Kentucky on regular runs, and Kentucky sought to impose a tax on the use of gasoline consumed in Kentucky. The Court invalidated the tax “computed and imposed upon the use of the gasoline thus consumed.” 279 U. S., at 248.
In the present case, Illinois is the State of storage of United’s fuel before loading. If Illinois imposed a tax on the basis of that storage but measured the tax only by the fuel consumed over Illinois, a lower tax would result. The dangers of multiple taxation and possible tax windfalls, already suggested as justifying the Helson decision, would not be present if the tax were imposed on storage prior to loading but were measured by consumption. Multiple taxation and tax windfalls are avoided because only one State — the State of storage before loading — has a local event upon which a tax is imposed. Under Helson, States over which the planes fly will be unable to impose a tax on mere consumption.
The use of a method of tax measurement that is intimately related to interstate commerce is not automatically unconstitutional. Tolls on the use of facilities that aid interstate commerce have been upheld even when measured by passengers or by mileage traveled on the highways of a State. Evansville-Vanderburgh Airport Authority District v. Delta Airlines, 405 U. S. 707 (1972); Interstate Busses Corp. v. Blodgett, 276 U. S. 245 (1928). Upon the facts before us, we see no constitutional barrier to the use of the “burn off” rule by Illinois to measure the tax imposed for storage before loading.
Since we now determine that the federal compulsion felt by two justices of the Illinois court is not warranted, we remand the case to avoid the risk of “an affirmance of a decision which might have been decided differently if the court below had felt free, under our decisions, to do so.” Perkins v. Benguet Mining Co., 342 U. S., at 443. We, of course, express no opinion on the construction of the temporary-storage provision under state law.
The judgment of the Supreme Court of Illinois is vacated and the case is remanded to that court for further proceedings.
T. ■ , , It is so ordered.
Turbine (jet) fuel for use at O’Hare is shipped by common carrier pipeline from the supplier’s Indiana terminals to a 15-million-gallon storage facility at Des Plaines, Illinois. App. 168-169. Normally, three deliveries are made each month to this facility. App. 129. Smaller quantities of fuel are transferred by pipeline to facilities maintained by United at O’Hare.
Turbine fuel for use at Midway and aviation gasoline for both airports is transported from Indiana by common carrier tank truck to airport storage facilities. App. 159.
The parties have stipulated that the period of storage ranges from two to 12 days. App. 38. The Des Plaines storage facilities are not owned by United; it and another airline jointly lease the facilities. United shares in the cost of repairs, the risk of loss, and the employment of a managing agent. App. 132, 168.
App. 173-174. United uses fuel from the storage facilities for its intrastate training flights and for the intrastate leg of flights that stop at both Chicago and Moline, Illinois. 49 Ill. 2d 45, 47-48, 273 N. E. 2d 585, 586. United also engages in interstate charter flights. App. 37 n. 6.
The temporary-storage provision excepts
“(d) the temporary storage, in this State, of tangible personal property which is acquired outside this State and which, subsequent to being brought into this State and stored here temporarily, is used solely outside this State or physically attached to or incorporated into other tangible personal property that is used solely outside this State.” § 439.3.
The Illinois court’s interpretation of the temporary-storage provision makes it clear that loading into the tanks of the airplane is a relevant event but is not the taxable event. The court indicated that the temporary storage exemption suspended the effect of otherwise taxable events:
“To put it another way, the legislature has stated that the temporary storage and the withdrawal therefrom are not taxable uses, if the property in question is to be used solely outside the State. It is clear that if United was to withdraw its fuel from storage at Des Plaines and the airports and transport it outside the State for use elsewhere, as for example at an airport in nearby Wisconsin, the exemption would apply and neither the storage, nor the withdrawal, nor the transportation of the fuel outside the State would be uses subject to the tax.” 49 Ill. 2d, at 55, 273 N. E. 2d, at 590.
Under this view, all the fuel is “used” and subject to Illinois tax when it is temporarily stored or withdrawn from storage. The taxable event is nullified, however, if the fuel is transported from the State for consumption elsewhere.
Although this use of a subsequent event to define the effect of a prior event may appear somewhat unusual, the result may be said to be compelled since fuel in transit may not be constitutionally taxed. See Michigan-Wisconsin Pipe Line Co. v. Calvert, 347 U. S. 157 (1954). A similar exemption for gasoline “exported or sold for exportation from the State” was present in the Wyoming statute challenged in Edelman v. Boeing Air Transport, 289 U. S. 249, 250 (1933).
Amici have urged reconsideration of Edelman, arguing that it represents “a high-water mark in the Court’s search in the early thirties for formulas that would assist states in finding additional sources of revenue.” Brief for American Airlines et al. 13.
Although this is a general state tax, rather than a toll on commerce, this Court has recognized that interstate commerce can be “required to pay a nondiscriminatory share of the tax burden.” Braniff Airways v. Nebraska State Board of Equalization, 347 U. S. 590, 598 (1954). In Helson v. Kentucky, 279 U. S. 245 (1929), in contrast, the ferry boat was asked to bear more than its “nondiscriminatory share” when it was taxed only for passing through Kentucky waters.
Those justices of the Illinois court who relied on Helson did not consider, apparently, any interpretation of Helson that would prevent multistate taxation. They suggested that an adoption of the “burn off” rule would allow taxation by every State over which United’s planes fly. 49 Ill. 2d, at 51, 273 N. E. 2d, at 588.
United successfully calculated and paid the state tax under the “bum off” interpretation for eight years. App. 41. No suggestion has been made that the recordkeeping procedures were an intolerable burden on commerce or that special equipment must be installed to measure fuel consumption.
Ill. Rev. Stat., c. 120, § 439.1 et seq.