The long-distance links of the nation's road system were under pressure as well, and federal and state highway officials sketched some grand plans to meet the expected demand. One of the boldest dreamers of all was President Franklin D. Roosevelt, a man who loved long drives through the countryside in a car. He suggested that the government buy a 2-mile-wide strip of land stretching from one coast to the other, with some of it to be sold for development and the rest used for a magnificent toll highway. By 1944 this scheme had been brought down to earth by Congress, which passed a bill offering the states 50 percent federal funding of a 40,000-mile arterial network. Little could be done with a war on, however, and progress was fitful in its hectic aftermath. But President Dwight D. Eisenhower turned that basic vision into one of the greatest engineering projects in history.

As a former military man, Eisenhower was keenly interested in transportation. When he was a young lieutenant in 1919, he had traveled from Washington to San Francisco with a caravan of cars and trucks, experiencing delays and breakdowns of every kind and averaging 5 miles an hour on the miserable roads. At the opposite extreme, he had noted the swift movement of German forces on autobahns when he was commanding Allied forces in Europe during World War II. The United States, he was convinced, needed better highways.

Getting legislation—and funding—through Congress was no small task. In 1954 Eisenhower appointed an advisory committee, chaired by his wartime colleague General Lucius Clay, to establish consensus among the many parties to the nation's road-building program. It took 2 years, but the quiet diplomacy and technical expertise of the committee's executive secretary, a Bureau of Public Roads engineer named Frank Turner, ultimately helped steer legislation through the political shoals in both the House and the Senate. In 1956 Eisenhower signed into law the act initiating the epic enterprise known as the National System of Interstate and Defense Highways. It called for the federal government to pay $25 billion—90 percent of the estimated total cost-toward building limited-access expressways that would crisscross the nation and speed traffic through and around cities.

The network, to be completed by 1972, would incorporate some older toll roads, and its length was ultimately set at 44,000 miles. Four 12-foot lanes were the stipulated minimum, and many sections would have more, along with 10-foot shoulders. The system would include 16,000 entrances and exits, dozens of tunnels, and more than 50,000 overpasses and bridges. To ensure that the roads would hold up under the anticipated truck traffic, hundreds of different pavement variations were tested for 2 years at a site in Illinois.

The price tag for the interstate highway system turned out to be five times greater than anticipated, and work went on for 4 decades—not without controversy and contention, especially on the urban front. Several cities, refusing to sacrifice cherished vistas or neighborhoods to an expressway, chose to do without. By the mid-1970s cities were permitted to apply some of their highway funds to mass transit projects such as subways or rail lines. But for the most part the great project moved inexorably forward, and by the 1990s cars, trucks, and buses were traveling half a trillion miles a year on the interstates—a good deal more safely than on other U.S. roads.