Monument of the Millennium
The Interstate Highway System, first established as a national priority by President Dwight D. Eisenhower in the mid-1950s, revolutionized travel, economies and the daily standard of living in North America by providing an efficient means of direct, high-speed transportation for individuals and businesses in the United States, Canada and Mexico. The 42,800-mile system, built on a North-South/East-West grid, has hundreds of bridges, overpasses, interchanges and thousands of miles of pavement. Following the prototype of a limited-access highway provided by the Pennsylvania Turnpike, completed in 1940, the interstate highway is fully access controlled, with all intersections at different grades and access provided through interchange ramps. There are more than 55,000 grade separations and other bridges, and curves are engineered for safe turns. All interstate highways have at least four lanes, and conveniently spaced rest areas are available throughout the system. The system's design has ensured the safe and efficient flow of intrastate and interstate traffic. The system carries 20 percent of traffic, although it only covers 1 percent of the U.S., and is credited with saving more than 187,000 lives and preventing 12 million injuries. It is estimated that the Interstate Highway System saved $6 for every $1 spent on its construction.