List of Interstate Highways in Washington
Interstate 90 (I-90) is the longest primary Interstate Highway in Washington, which connects Seattle to Spokane and the Idaho border, measuring , while I-82, connecting the Oregon border city of Umatilla to Elensburg via Yakima, is the shortest at . The longest auxiliary Interstate Highway in Washington is I-405, a bypass of Seattle through the Eastside, at , and the shortest is I-705, a spur into downtown Tacoma, at . One route, I-605, has been proposed over the years to form another Eastside bypass, however there are no plans to construct this fifth auxiliary route.
After passage of the Federal Aid Highway Act of 1956, which formed the Interstate Highway System, the American Association of State Highway Officials had approved I-5 and I-90 across Washington on August 17, 1957. I-82 was approved on October 17, 1957, two months after I-5 and I-90, as part of a addition to the Interstate Highway System.
Trans-Siberian Highway
The Trans-Siberian Highway is the unofficial name for a network of federal highways that span the width of Russia from the Baltic Sea of the Atlantic Ocean to the Sea of Japan. In the Asian Highway Network, the route is known as AH6. It stretches over from St. Petersburg to Vladivostok. The road disputes the title of the longest national highway in the world with Australia's Highway 1.
The highway became fully paved on 12 August 2015.