The system of U.S. highways numbered within a nation-wide grid that is maintained by state or location governments. The system was established in 1926. The numbers and locations are coordinated by the American Association of State Highway Transportation Officials (AASHTO). North-to-south highways are odd-numbered, with the lowest numbers in the eastern U.S. and highest in the western U.S. West-to-east highways are even-numbered, with the lowest numbers in the northern US and highest numbers in the southern US. Major east-west routes have numbers ending in “0” (e.g., U.S. 60), and major north-south routes have numbers ending in “1” (e.g., U.S. 91). The Interstate Highway System has largely replaced the U.S. highway System for long-distance through traffic, although many important regional connections are still made by U.S. highways.