The system of United States Numbered Highways (often called U.S. Routes or U.S. Highways) is an integrated system of roads and highways in the United States numbered within a nationwide grid. As these highways were coordinated among the states, they are infrequently referred to as Federal Highways, but they have always been maintained by state or local governments since their initial designation in 1926. The numbers and locations are coordinated by the American Association of State Highway and Transportation Officials (AASHTO). The only federal involvement in the AASHTO is a non-voting seat for the United States Department of Transportation. North-to-south highways are odd-numbered, with lowest numbers in the east and highest numbers in the west. Similarly, west-to-east highways are even-numbered, with the lowest numbers in the north and highest numbers in the south.