Federal-Aid Highway Act signed

On June 29, 1956, President Dwight D. Eisenhower signed the Federal-Aid Highway Act in Washington, creating the Interstate Highway System and the Highway Trust Fund. Congress authorized roughly 41,000 miles of controlled-access highways, and federal gasoline taxes supplied the long-term funding mechanism for the project. Eisenhower supported the law in part because his 1919 Army convoy experience and the Cold War defense climate convinced him that the United States needed fast overland transportation for commerce, evacuation, and military movement.

The act joined domestic prosperity to Cold War defense planning by treating highways as both an economic engine and a national-security requirement. Business groups, suburban developers, and automobile interests wanted faster commercial transportation, while defense planners wanted routes that could move troops and disperse civilians in the event of nuclear attack. The new system also intensified social tensions in many cities, because interstate construction often cut through established urban neighborhoods and accelerated suburban migration.

The Interstate Highway System itself followed directly from the 1956 law and reshaped transportation, freight movement, and metropolitan growth for decades. The federal road-building model created by the act also fed into later transportation policy, including the Department of Transportation established in 1966 and the continuing federal-state highway partnership financed through the Highway Trust Fund.