Federal planning for a transcontinental road system originated in the 1930s and in 1938, Congress passed the Federal-Aid Highway Act to study the feasibility of a national highway system. However, the 1944 Act of the same name, which established "a national system of interstate highways," did not authorize funding for the project.  It was not until passage of the Federal-Aid Highway Act of 1952 that monies were set aside ($25 million per year for the following two fiscal years) specifically for interstate construction and in 1956, legislation raised the annual authorization to $175 million per year.

The total cost of the Dwight D. Eisenhower National System of Interstate and Defense Highways as reported to Congress in 1991: $128.900 billion.

— Source: U.S. Department of Transportation, Federal
Highway Administration (FHWA)