AASHTO
A Policy on Design StandardsInterstate System
A Policy on Design StandardsInterstate System, American Association of State Highway and Transportation Officials, Washington, D.C., July 1991).
Wikipedia Article: 7/9/13
Standards for Interstate Highways in the United States are defined by the American Association of State Highway and Transportation Officials (AASHTO) in the publication A Policy on Design Standards - Interstate System. For a certain highway to be considered an Interstate, it must meet these construction requirements or obtain a waiver from the Federal Highway Administration.