State Route 520 (SR 520) is a 13-mile (21 km) state highway and freeway in the Seattle metropolitan area in the U.S. state of Washington. Connecting Seattle to the Eastside region of King County across the Evergreen Point Floating Bridge on Lake Washington, it intersects Interstate 5 (I-5) in Seattle, I-405 in Bellevue, and SR 202 in Redmond. It was designated as a freeway in 1964, but was not fully constructed until the late 1970s. Increased traffic on the corridor, spurred in part by expansion of the Microsoft headquarters in Overlake, led to the addition of high-occupancy vehicle lanes and new interchanges in the 1990s. In April 2016, the original floating bridge was replaced by a wider one as part of a multibillion-dollar expansion program that is scheduled to be completed in the 2020s. The program includes the construction of a new bicycle and pedestrian path, bus stations, and interchanges. (Full article...)