U S interstate highway system

The Dwight D. Eisenhower System of Interstate and Defense Highways, inaugurated in June 1956 by the Federal-Aid Highway Act, is a 41,000-mile (66,000-kilometer) network linking 90 percent of the major cities whose population exceeds 50,000 and many other urban centers in the mainland United States. The bill earmarked $25 billion to be spent between 1957 and 1969, and the system was to be completed by 1972. Sinclair Weeks, then secretary of commerce, somewhat extravagantly claimed it to be the greatest public works project in history.