Federal law requires most interstate truckers to obtain a permit (Federal Permit) that reflects compliance with certain federal requirements. The 1965 version of the law authorized States to require proof that a truck operator had such a permit. By 1991, 39 States demanded such proof, requiring a $10 per truck registration fee (State Registration) and giving each trucker a stamp to affix to a multistate "bingo card" carried in the vehicle. Finding this scheme inefficient and burdensome, Congress created the current Single State Registration System (SSRS), which allows a trucking company to fill out one set of forms in one State (base State), thereby registering its Federal Permit in every participating State through which its trucks travel. 49 U. S. C. §14504(c). The base State can demand proof of the Federal Permit, proof of insurance, the name of an agent to receive service of process, and a fee equal to the sum of the individual state fees. §§14504(c)(2)(A)(i)-(iv). The SSRS prohibits a State from imposing any additional "State registration requirement." §14504(b). Michigan Comp. Laws Ann. §478.2(2) imposes an annual $100 fee on each Michigan license-plated truck operating entirely in interstate commerce. Petitioner interstate trucking companies subject to §478.2(2) sought to have it invalidated, but the Michigan Court of Claims refused. The State Court of Appeals affirmed, holding that, because the fee is imposed for the administration of the State's Motor Carrier Act and for enforcement of state safety regulations, it is not a "registration requirement" pre-empted by §14504(b).

Held: Section §14504 does not pre-empt Michigan's $100 fee. Pp. 5-13.

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