List of Interstate Highways in Utah
The Interstate Highways in Utah are maintained by the Utah Department of Transportation (UDOT). The Interstate Highway System is a nationwide system with only a small portion of these routes entering Utah. Originally, the State Road Commission of Utah, created on March 23, 1909 was responsible for maintenance, but these duties were rolled into the new UDOT in 1975. There are of Interstates within the state. The longest is Interstate 15 (I-15) at and the shortest is I-215 at . One unique former route is Interstate 415, which was never signed as such, and was only used as a temporary designation for the eastern portion of what is now the Interstate 215 belt loop around Salt Lake City.
Arkansas Highway System
Arkansas first established a statewide state highway system in 1924. This system labeled its routes in a "letter-number number" system such as A-11. The roads were all designated as "State Road l-nn" prior to the creation of the U.S. Numbered Highway System. Upon creation of the Harrelson Road Law, the US Route system came to Arkansas and the system was renumbered. This system has generally remained in place, with the major addition of the Interstate Highway System in 1965. The original system had just over 100 routes, mostly dirt paths that became unpassable after rain. Arkansas began using the same pavement techniques used for Dollarway Road, which was the longest continuous concrete pavement in the United States when completed in 1913.
These routes were signed with white cut-out shapes of Arkansas, which said "State Road" in addition to the route number. In the 1950s, the Araknsas Highway Department removed the "State Road" and instead printed "ARKANSAS" on top of the shields, with a line underneath the state name. The shields were changed to the current format circa 1971, though all numbers were within square shields. A wider sign was created later to allow three-digit routes to use the same font size as two-digit routes.