A state law prohibiting polished aluminum exteriors on commercial trucks was struck as unconstitutional for burdening interstate commerce. Congress later enacted a statute allowing states to regulate reflectiveness of truck exteriors on highways. Is this federal statute constitutional?

• A. Yes, because Article I Section 8 grants Congress authority to enact statutes authorizing states to impose burdens on interstate commerce that would otherwise be prohibited.
• B. No, because Congress cannot overrule Supreme Court decisions.
• C. Yes, because commercial trucks are instrumentalities of interstate commerce.
• D. No, because the law would still burden interstate commerce.

Answer: (C)

The key idea is Congress’s power to regulate instrumentalities of interstate commerce. Commercial trucks operating on highways are the means by which goods move across state lines, so they count as instrumentalities that Congress can regulate. When Congress acts to regulate those instrumentalities, it can also authorize states to regulate aspects of how those instrumentalities operate, especially to address safety or efficiency concerns. Here, Congress enacted a statute allowing states to regulate the reflectiveness of truck exteriors. That use of power fits within regulating the instrumentality itself and coordinating safety regulation across the states, so the statute is constitutional. Without this federal authorization, a state law prohibiting polished aluminum exteriors might burden interstate commerce, but the authorization changes the legal landscape by giving states room to regulate under a federal framework.