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 40
U.S. Route 40 (US 40), also known as the Main Street of America, is an east–west United States Highway. As with most routes whose numbers end in a zero, US 40 once traversed the entire United States. It is one of the first U.S. Highways created in 1926 and its original termini were in San Francisco, California and Atlantic City, New Jersey. In the western United States, US 40 was functionally replaced by Interstate 80 (I-80), resulting in the route being truncated multiple times. US 40 currently ends at a junction with I-80 in Silver Summit, Utah, just outside Park City.