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.
U.S. Route 99 in California
By 1968, US 99 was completely decommissioned with the completion of I-5 in Washington and California, but the highway's phasing out actually began July 1, 1964, thanks to the passage of Collier Senate Bill No. 64 on September 20, 1963. The bill launched a major program designed to greatly simplify California's increasingly complicated highway numbering system and eliminate concurrent postings like the aforementioned US 60/US 70/US 99. The highways that replaced it are:The stretch between Wheeler Ridge and Red Bluff is signed as SR 99 which makes it California's second-longest state highway behind SR 1. However, the newly enacted "Historic U.S. Route 99" extends from Indio starting from I-10 in the Coachella Valley all the way down the Imperial Valley to Calexico on the Mexican border with Mexicali, Baja California, Mexico.U.S. Route 99W was a short-lived alternate of US 99 in the Central Valley of California, running from north of Manteca via French Camp to Stockton. At the same time, from roughly 1929 to 1933, U.S. Route 99E ran to the east, having the same termini as US 99W.