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.
U.S. Route 46
U.S. Route 46 (US 46) is an east–west U.S. Highway completely within the state of New Jersey, running for , making it the shortest signed, non-spur U.S. Highway. The west end is at an interchange with Interstate 80 (I-80) and Route 94 in Columbia, Warren County on the Delaware River. The east end is in the middle of the George Washington Bridge over the Hudson River in Fort Lee, Bergen County while the route is concurrent with I-95 and US 1-9. Throughout much of its length, US 46 is closely paralleled by I-80. US 46 is a major local and suburban route, with some sections built to or near freeway standards and many other sections arterials with jughandles. The route runs through several communities in the northern part of New Jersey, including Hackettstown, Netcong, Dover, Parsippany-Troy Hills, Wayne, Clifton, Ridgefield Park, Palisades Park, and Fort Lee. It crosses over the Upper Passaic River at several points. The road has been ceremonially named the United Spanish–American War Veterans Memorial Highway.