The STOP China Act aims to address national security risks by prohibiting the use of federal funds for the procurement of certain vehicles and vehicle technologies from entities based in "covered nations." Congress expresses concern that the People's Republic of China (PRC) uses industrial policies to distort markets, increase U.S. dependence, and undermine domestic supply chains. The bill seeks to prevent U.S. taxpayer dollars from funding PRC-subsidized manufacturing and technology companies, confronting the PRC's military-civil fusion strategy in the transportation market. The legislation amends existing law and introduces new prohibitions, defining a "covered entity" broadly to include any entity based in, headquartered in, controlled by, or affiliated with a "covered nation" or "covered individual." A "covered vehicle" is defined as rolling stock produced by such an entity or incorporating an electric power train from one. The term "covered nation" refers to countries identified in 10 U.S.C. 4872(d), which typically includes China. The bill establishes two main funding prohibitions. First, it restricts Federal Transit Administration (FTA) funding from being used for procuring covered vehicles or related charging infrastructure. Second, it extends this prohibition to all other Department of Transportation appropriations, preventing their use for procuring covered vehicles or associated infrastructure. The United States Trade Representative, in consultation with the Attorney General and the Secretary of Transportation, is mandated to create and regularly update a public list of these prohibited covered entities, with exceptions for inspection, investigation, or motor vehicle safety research.