The American Association of State Highway and Transportation Officials (AASHTO) is responsible for maintaining the official records of the United States Numbered Highways. The AASHTO Special Committee on U.S. Route Numbering meets twice each year to consider applications from state highway and transportation agencies for changes to the Interstate, U.S. Numbered Highway and U.S. Bicycle Route Systems. The Special Committee screens all applications and makes recommendations to the AASHTO Executive Committee which administers the system. This 1989 edition of the United States Numbered Highways introduces a change in format. It is published in a looseleaf notebook and three-hole punched in order to print and distribute updates on an annual basis. When the changes become extensive, as they may within a period of five or more years, a new book will then be published.