A unanimous Supreme Court has held that the Federal Motor Carrier Safety Administration (FMCSA) did not violate U.S. environmental law by failing to conduct an environmental impact statement (EIS) of increased pollution from allowing Mexican trucks to operate in the United States beyond limited border zones. The Court's decision reversed the opinion of the Ninth Circuit Court of Appeals. That ruling required FMCSA to consider the pollution increase in a full EIS prior to issuing regulations governing applications and safety inspections for Mexican trucks to operate in the United States. See full story and background.