page_title: Washington State Route 518
section_title: History
hierarchical_section_title: Washington State Route 518 / History
caption_attribution_description: Southbound Interstate 5, at the eastern terminus of Washington State Route 518 in Tukwila.
context_page_description: State Route 518 is a 3.42-mile-long state highway located entirely within King County in the U.S. state of Washington. The freeway begins in Burien at an interchange with SR 509 and travels east to serve Seattle–Tacoma International Airport and intersect SR 99 in SeaTac. SR 518 continues east into Tukwila and ends at an interchange with Interstate 5, as the freeway becomes I-405. The highway was codified in 1937 as the western segment of Secondary State Highway 1L and designated as SR 518 during the 1964 highway renumbering. During the 1970s, the roadway was widened into a freeway to serve the airport and serves over 100,000 vehicles per day.
context_section_description: A highway between Burien and Tukwila has existed since the 1890s and was first codified in 1937 as a segment of SSH 1L, which extended from PSH 5 in Renton west to intersect PSH 1 and US 99 in Tukwila and end at SSH 1K south of Sunnydale, later renamed Burien. The section between PSH 5 in Renton and PSH 1 in Tukwila was removed in 1957 after the construction of the Seattle–Tacoma International Airport, located on PSH 1 and US 99. The remaining highway was later re-designated as SR 518 during the 1964 highway renumbering, being codified as such in 1970. The western terminus of SR 518, an interchange with SR 509, was opened to traffic in November 1968, while the Airport Expressway was opened in 1970 and widened in the 1990s by the Port of Seattle. The freeway segment between SR 99 and I-5 was built in the 1970s. No major revisions to the route of SR 518 have occurred since the 1990s, however SR 99 from SR 518 to SR 599 was removed to the highway system in 2003.
  Beginning in 2005, an elevated light rail guideway was constructed on the north side of SR 518, for Sound Transit's Central Link line serving Downtown Seattle, the Rainier Valley and Sea-Tac Airport. The construction led to nighttime closures of the highway and other interruptions until construction finished in 2007. Tukwila International Boulevard station was built to the north of SR 518 at its interchange with SR 99 (International Boulevard) near Sea-Tac Airport.
caption: Southbound I-5 at its interchange with I-405 and SR 518 in Tukwila.
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot A540", "Image Orientation": "Horizontal (normal)", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2007:08:20 15:35:49", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "196", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "180", "Thumbnail YResolution": "180", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "5108", "Thumbnail JPEGInterchangeFormatLength": "3885", "EXIF ExposureTime": "1/320", "EXIF FNumber": "9/2", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2007:08:20 15:35:49", "EXIF DateTimeDigitized": "2007:08:20 15:35:49", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "5", "EXIF ShutterSpeedValue": "133/16", "EXIF ApertureValue": "139/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "139/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "80", "EXIF FocalLength": "15783/1000", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2272", "EXIF ExifImageLength": "1704", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "2272", "Interoperability RelatedImageLength": "1704", "EXIF InteroperabilityOffset": "2824", "EXIF FocalPlaneXResolution": "90880/9", "EXIF FocalPlaneYResolution": "1704000/169", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Landscape"}