Interstate Highway shields
Standard Interstate, wide
California- and Iowa-style Interstate
The Interstate Highway System is a federally funded and administered (but state-maintained) system of
freeways that forms the transportation backbone of the U.S., with millions of Americans relying on it for commutes and freight transport daily. Interstate highways are all constructed to
precise standards, designed to maximize high-speed travel safety and efficiency. Interstate Highways also contain auxiliary routes, which are normally assigned a three-digit route number. All Interstate Highways are part of the
National Highway System, a network of highways deemed essential to the defense, economy, and mobility of the country.