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.
Interstate 10 in Texas
Interstate 10 (I-10) is the major east–west Interstate Highway in the Southern United States. In the U.S. state of Texas, it runs east from Anthony, at the border with New Mexico, through El Paso, San Antonio and Houston to the border with Louisiana in Orange, Texas. At just under , the Texas segment of I-10, maintained by the Texas Department of Transportation, is the longest continuous untolled freeway in North America that is operated by a single authority. It is also the longest stretch of highway with a single designation within a single state. Mile marker 880 and its corresponding exit number in Orange, Texas, are the highest numbered mile marker and exit on any freeway in North America. After widening was completed in 2008, a portion of the highway west of Houston is now also believed to be the widest in the world, at 26 lanes. There is a wider section in China on the G4 Beijing–Hong Kong–Macau Expressway; however, that section is a toll plaza approach.