Final answer:
The act of Congress tying federal highway aid to the adoption of certain speed limits by states is based on the Commerce Clause and the concept of Fiscal Federalism. Congress uses both expressed and implied powers to regulate interstate commerce and influence state policies.
Step-by-step explanation:
An act of Congress tying federal highway aid to the states to the adoption of certain speed limits is based upon the constitutional power known as the Commerce Clause. This clause is part of the enumerated powers given to Congress by the Constitution, specifically within Article I, Section 8. It grants Congress the authority to regulate interstate commerce, which includes the ability to establish a national transportation system. Additionally, practices such as Fiscal Federalism demonstrate the use of federal funding to incentivize or mandate state compliance with national policies.
Congress also utilizes its implied powers, often referenced as the 'elastic clause' or 'necessary and proper clause' from Article I, Section 8 of the Constitution, to exert control in areas not explicitly mentioned in the document. Implied powers have allowed Congress to enact a variety of regulations that extend beyond direct commerce management to areas impacting the economy and public welfare, such as the establishment of a minimum wage, regulation of air and water pollution, and setting national standards for driving and transportation safety.