U.S. Route 20
U.S. Highway 20 (US 20) is an east–west United States highway that stretches from the Pacific Northwest all the way to New England. The "0" in its route number indicates that US 20 is a coast-to-coast route. Spanning , it is the longest road in the United States, and particularly from Newport, Oregon to Boston, Massachusetts, the route is roughly parallel to that of the newer Interstate 90 (I-90), which is in turn the longest Interstate Highway in the U.S. There is a discontinuity in the official designation of US 20 through Yellowstone National Park, with unnumbered roads used to traverse the park.
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.