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.
List of U.S. Highways in Michigan
In Michigan, the US Highway System covers about of mainline highways and another of special routes. There are 13 mainline highways and 30 special routes in total, including one business route that is unsigned. Two of the mainline highways in the Upper Peninsula exit the state and re-enter, resulting in two discontinuous segments of highway for each in Michigan. The longest US Highway in the state is US Highway 23 (US 23) at just over spanning from the Ohio state line north to the Straits of Mackinac in the Lower Peninsula, while the shortest is the segment of US 8 south of Norway in Dickinson County. Special routes range in length from about for Business US 2 (Bus. US 2) in Ironwood to for Bus. US 131 in Kalamazoo.