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.
Interstate 10
Interstate 10 (I-10) is the southernmost cross-country Interstate Highway in the American Interstate Highway System. It stretches from the Pacific Ocean at California State Route 1 (Pacific Coast Highway) in Santa Monica, California, to I-95 in Jacksonville, Florida. Major cities connected by I-10 include (from west to east) Los Angeles, Phoenix, Tucson, El Paso, San Antonio, Houston, Baton Rouge, New Orleans, and Jacksonville. This freeway is part of the originally planned Interstate Highway network that was laid out in 1956, and its last section was completed in 1990. I-10 is the fourth-longest Interstate Highway in the United States, following I-90, I-80, and I-40. About one-third of its length is within the state of Texas, where the freeway spans the state at its widest breadth.