The Federal-Aid Highway Act is a significant piece of legislation in the United States that was first enacted in 1956. It aimed to create a nationwide system of interstate highways, improving transportation and commerce across the country. The act authorized federal funding to assist states in constructing and maintaining these highways, which are crucial for connecting cities and facilitating trade. This act led to the establishment of the Interstate Highway System, which spans over 47,000 miles. It has played a vital role in shaping modern transportation, enhancing road safety, and promoting economic growth by making travel and shipping more efficient across the nation.