Department of Transportation v. Public Citizen

Background

The dispute involved the Federal Motor Carrier Safety Administration (FMCSA), a Department of Transportation agency, and parties who challenged two FMCSA rules that would govern Mexican-domiciled motor carriers operating in the United States. FMCSA prepared an Environmental Assessment (EA) and a Finding of No Significant Impact (FONSI) that assumed the rules themselves would not change trade volume, and it limited its environmental review to inspection-related effects. The Court of Appeals disagreed, holding FMCSA should have prepared a full Environmental Impact Statement (EIS) and a full Clean Air Act (CAA) conformity review because the entry of Mexican trucks was “reasonably foreseeable.”

Reasoning

The Supreme Court asked whether NEPA or the CAA required FMCSA to analyze environmental effects caused by Mexican trucks entering the United States when FMCSA lacks authority to prevent that entry. The Court found FMCSA must register carriers that are “willing and able” to meet safety and financial rules and thus cannot categorically block cross-border operations. A mere “but for” link between FMCSA’s regulations and later truck entry was insufficient; NEPA requires a reasonably close causal relationship and a rule-of-reason analysis. Because FMCSA could not use an EIS to change the outcome, an EIS would not serve NEPA’s decisionmaking or public-information purposes. Under the CAA, emissions are only covered if the agency can practicably control them; FMCSA cannot control or maintain control over Mexican truck emissions, so no full conformity review was required.

Real world impact

The ruling allows FMCSA to proceed with the challenged safety and application rules without preparing a full EIS or a full CAA conformity determination for emissions from Mexican trucks, because FMCSA lacks legal authority to prevent those trucks’ entry. The Supreme Court reversed the Court of Appeals and sent the case back for further proceedings consistent with this opinion.