Interstate-Guide - Purpose

The allure of the open road beckons. Interstate Highways create the backbone of the American roadway network. Interstates facilitate the movement of goods and services and allow for high speed travel from one coast of the country to the other. In addition Interstate Highways play an integral role in the local traffic movements of metropolitan areas and promote growth.

The Interstate System was designated in 1956 under the presidency of Dwight D. Eisenhower. Originally constituted of 44,000 miles, the network now includes over 65,000 miles of federally maintained roadway including routes in all 50 states and the U.S. Territory of Puerto Rico. The national network is still expanding with new corridors under construction and in the planning stages.

Interstate Highways must meet strict engineering standards ranging from shoulder and lane width minimums to Interchange interval spacing requirements. These rules are put in place to maintain a consistency on the system from coast to coast. Minimum speed limits on Interstate Highways are generally 55 mph with a maximum at 75 mph. Exceptions do occur in substandard locations such as Interstate 59 in Laurel, Mississippi, in tunnels such as Interstate 10 in Mobile, Alabama, and through sensitive natural areas such as Franconia Notch, New Hampshire along Interstate 93. Where possible, substandard sections are reconstructed to modern standards or bypassed unless special exception status is granted.

These are the fundamentals of Interstate Highways and some of the practical uses of them. In the road enthusiast community, Interstates are generally described as a major point of interest. These roadways allure us with their uniqueness in the overall highway spectrum. Unique in that Interstates offer a viable alternative to the stop and go traffic movements of local surface streets and offer an opportunity to utilize cruise control for a long period of time. While Interstates in heavily built up areas are often compared to virtual parking lots, Interstates often offer striking views of a downtown skyline, soar above housetops on a high level viaduct, or tuck themselves below a commercial district in a suppressed fashion. What makes this so thought provoking is that the same route that may cut through an urbanized ghetto may also, several hundred miles away, cross a pristine mountain landscape or hug a lake shore or trudge through an open wetlands area. Think also that traveling in the scorching desert sun along Interstate 8 or in the sultry night air of the Gulf Coast on Interstate 10 can link us to routes that also offer frigid scenes of Interstate 25 in Wyoming or the shimmering skyline of New York City along Interstate 278. It's all the same system!

On Interstate-Guide you will find background information, mileage figures, and other facts about every Interstate Highway in the system. In addition and thanks to our many great viewers and contributors, we offer local perspectives and information, photos of endpoints, and maps when available of these great ribbons of asphalt and concrete.

Although most Interstate Highways are clearly signed and identified on the nation's freeway system, there are a few of them that are not signed for logistical or clarity reasons. These "hidden" Interstates are treated as part of a state's Interstate Highway System mileage, but they are not shielded. In addition, there are many proposed additions to the Interstate Highway System. We have attempted to uncover as many of these proposals as possible and publicize them here, with links to those future Interstate corridors that are also Congressional High Priority Corridors. Finally, several Interstate highways have been signed at one time but have since been decommissioned, sometimes because a freeway is no longer Interstate standard and other times when a short segment of freeway is absorbed by another, longer freeway. We do not even attempt to identify all of the once-proposed Interstates that have not been constructed unless we have specific information pertaining to these routes; for more on these, we recommend Three-Digit Interstates (3dis) at

As we develop AARoads into a world-class road enthusiast experience, we hope you will join us in hitting the road!

Page Updated June 17, 2003.

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