Commuters saw much to celebrate at the "Futurama" exhibit in the 1939 New York World's Fair. In the exhibit's vision of what transportation would be like twenty years hence, fourteen-lane superhighways connected the nation at speeds up to 100 miles per hour. In-car radio beams separated vehicles from each other at safe, uniform distances. City traffic moved at regulated levels of 50 miles per hour through traffic.

Two hundred miles south at the White House, President Franklin D. Roosevelt expressed only slightly more modest ambitions. His 1939 Bureau of Public Roads report recommended an approximately 30,000-mile, non-toll "special system of direct interregional highways, with all necessary connections through and around cities, designed to meet the requirements of the national defense and the needs of a growing peacetime traffic of longer range."

The second world war, financing disputes, and labyrinthine power struggles delayed construction nearly two decades. By 1955, President Dwight D. Eisenhower argued before Congress that the highway could wait no longer. The President contrasted his experiences on a torturously-slow Army cross-country motor convoy in the United States with the efficient Allied advance through Germany on that nation's autobahn network. "Our unity as a nation is sustained by free communication of thought and by easy transportation of people and goods," he concluded.

The Federal-Aid Highway Act of 1956 designated 41,000 miles of roads for the National System of Interstate and Defense Highways. The Act mandated uniform interstate design standards, full control of access, minimum four-lane segments, and the elimination of highway and railroad-highway grade crossings. To give a sense of the system's scope, the grade crossing prohibition alone required the construction of more than 55,000 bridges. A combination of designs submitted by Missouri and Texas yielded the highway numbering scheme (odd numbers for north-south routes and even numbers for east-west routes, with numbers increasing from east to west and north to south) as well as the familiar red, white, and blue interstate shield.

More than 10,000 miles of interstate opened by 1960, then another 10,000 by 1965 and another by 1970. Today, traffic follows more than 40,000 miles of interstate highways. Given the scope of the United States, however, the system represents only about one percent of the nation's road network. Yet the interstate highway system carries nearly one quarter of all roadway traffic and nearly ninety percent by value of the country's commercial cargo.

"By increasing speed and expanding access, freight costs have been reduced substantially," explain Wendell Cox and Jean Love, public policy consultants with the Wendell Cox Consultancy. "By improving inter-regional access, the interstate highway system has helped to create a genuinely national domestic market with companies able to supply their products to much larger geographical areas, and less expensively."

Today, as Congress prepares its six-year reauthorization of the federal highway bill, some argue for truck-only toll lanes along major highway corridors. With trucks safely separated from car traffic, shipping companies would be allowed to use higher-capacity Longer Combination Vehicles, or LCVs.

U.S. House Transportation & Infrastructure Committee Chairman Don Young says Congress will "review the options and locations" of a test program of the trucks-only lanes concept. Until then, it's relegated with the in-car radio beams to Futurama.