Original: The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly called the Interstate Highway System (or simply, the Interstate System), is a network of limited-access highways (also called freeways or expressways) in the United States that is named for President Dwight D. Eisenhower, who championed its formation.
Simplified: The Dwight D. Eisenhower National System of Interstate and Defense Highways (often called the Interstate Highway System, Interstate or I-), is a group of roads in the United States.