The story of America’s interstates is usually told as a straightforward tale of postwar progress, but the real origins are stranger and more contested than the green signs suggest. The Dwight D.

There are a number of different road designations in the United States, from highways and freeways to interstates and routes, and it can cause some confusion with different laws and regulations.

A consensus study mandated by US Congress to advice on the public policies and investments needed to restore and upgrade the Interstate Highway System to its role as a premier system that meets the ...