List of Interstate Highways in Arizona
The Interstate Highways in Arizona are the segments of the Dwight D. Eisenhower System of Interstate and Defense Highways that are owned and maintained by the U.S. state of Arizona, totaling about 1,169 miles (1,881 km). Arizona has a total of six Interstate Highways, all of which are mainline highways; there are no auxiliary highways. The longest Interstate in Arizona is Interstate 10 (I-10), which traverses east-west through the southern and central parts of the state, serving Phoenix. There are also a total of fourteen active business routes and eight former routes, which were either business loops or spurs for all main highways except I-15. All of Arizona's existing Interstate Highways have overtaken or replaced some U.S. Routes, which either involved decommissioning or running concurrent with the existing route.
| Interstate Highways of the Arizona State Highway System | |
|---|---|
Example signage from Arizona's Interstate System | |
Interstate Highways highlighted in red Active business routes highlighted in blue | |
| System information | |
| Maintained by ADOT | |
| Length | 1,169.17 mi (1,881.60 km) Business Routes not included |
| Formed | 1957 |
| Highway names | |
| Interstates | Interstate X (I-X) |
| US Highways | U.S. Route X (US X) |
| State | State Route X (SR X) |
| System links | |
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The Arizona Department of Transportation (ADOT) is the agency responsible for building and maintaining the Interstate Highways in the Arizona State Highway System. These highways are built to Interstate Highway standards, which are freeways that have a 75-mile-per-hour (121 km/h) speed limit in rural areas and a 65 mph (105 km/h) speed limit in urban areas. The numbering scheme used to designate the Interstates was developed by the American Association of State Highway and Transportation Officials (AASHTO), an organization composed of various state departments of transportation in the United States.