High Intensity and Diamond Grade Stop Signs Meet DOT and MUTCD State and Federal Guidelines
Interstate Highways are signed by a number placed on a trademarked red, white, and blue sign. The colors red, white, and blue are chosen because they are the colors of the American flag. In the original design, the name of the state was displayed above the highway number, but in many states, this area is now left blank. The sign usually measures 36 inches (91 cm) high, and is 36 inches (91 cm) wide for two-digit Interstates or 45 inches (110 cm) for three-digit Interstates