Washington State Route 518 (Wash.)

found: Work cat.: SR 518 north airport expressway/SR 99 interchange to I-5/I-405 interchange : environmental assessment, 2006.

found: Wikipedia, Jan. 18, 2006:List of Washington State Routes/SR 518 (State Route 518 is a state highway in the U.S. state of Washington. It extends just under 3.5 miles (5.6 km) from Burien in the west to Tukwila in the east.)

found: Highways of Washington State, via WWW, Jan. 18, 2006:State Route 518 (When first posted as such in January 1964, SR 518 began at Jct SR 509 in Burien and headed east to Jct US 99/SR 405 north of Seattle-Tacoma International Airport. Where SR 518 ended, SR 405 began. During the late 1960s and early 1970s, SR 518 was moved to a new freeway that connected Burien with Tukwila. The eastern terminus of SR518/western terminus of I-405 was shifted from Jct US 99 to Jct I-5 after I-5 opened from Downtown Seattle to Midway in January 1967. The western terminus of SR 518 was shifted a few hundred feet east when SR 509 was moved from 1st Ave S to the Burien Freeway in the late 1960s. Today, SR 518 is 3.42 miles long. Before 1964, SR 518 had been part of SSH 1L. Secondary State Highway 1L, SSH 1L was added to the state highway system in 1937. This route began at Jct PSH 5 (now SR 167) in the south end of Renton and headed west, ending at Jct SSH 1K in Burien. In 1957, the Renton to PSH 1 (US 99/I-5) section of SSH 1L was transferred to the Renton Branch of PSH 1 (I-405). The remainder of SSH 1L from I-5 to Burien is now SR 518.)