 State Route 99 | ||||
|---|---|---|---|---|
| Pacific Highway William P. Stewart Memorial Highway | ||||
 A map of the Seattle metropolitan area with SR 99 highlighted in red. | ||||
| Route information | ||||
| Maintained by WSDOT | ||||
| Length | 48.97 mi[1] (78.81 km) | |||
| Existed | 1969–present | |||
| Southern segment | ||||
| South end |  I-5 in Fife | |||
| Major intersections |
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| North end |  SR 518 in SeaTac | |||
| Northern segment | ||||
| South end |  SR 599 in Tukwila | |||
| Major intersections | ||||
| North end |   I-5 / SR 526 / SR 527 in Everett | |||
| Location | ||||
| Country | United States | |||
| State | Washington | |||
| Counties | Pierce, King, Snohomish | |||
| Highway system | ||||
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State Route 99 (SR 99), also known as the Pacific Highway, is a state highway in the Seattle metropolitan area, part of the U.S. state of Washington. It runs 49 miles (79 km) from Fife to Everett, passing through the cities of Federal Way, SeaTac, Seattle, Shoreline, and Lynnwood. The route primarily follows arterial streets, including Aurora Avenue, and has several freeway segments, including the tolled SR 99 Tunnel in Downtown Seattle. SR 99 was officially named the William P. Stewart Memorial Highway by the state legislature in 2016, after a campaign to replace an unofficial moniker honoring Confederate president Jefferson Davis.
SR 99 was originally a section of U.S. Route 99 (US 99), which was once the state's primary north–south highway before the construction of I-5. US 99 was created in 1926 and replaced earlier local roads that date back to the 1890s and state roads designated as early as 1913. The highway was moved onto the Alaskan Way Viaduct in 1953, replacing a congested stretch through Downtown Seattle, and other sections were built to expressway standards in the 1950s.
US 99 was ultimately replaced by the Tacoma–Everett section of Interstate 5 (I-5), which opened in stages between 1965 and 1969. The route was decertified in 1969, and SR 99 was created to keep segments of the highway under state control. After decades of crime on some sections of SR 99, various city governments funded projects to beautify the highway and convert it into a boulevard. A section of the highway in Tukwila was transferred to city control in 2004, creating a two-mile (3.2 km) gap in the route between the interchanges of SR 518 and SR 599.
The Alaskan Way Viaduct was closed on January 11, 2019, and was replaced with a downtown bored tunnel that opened on February 4, 2019. The replacement project was spurred by the 2001 Nisqually earthquake, which damaged the viaduct and left it vulnerable to further damage, as well as city plans to revitalize the Seattle waterfront. The $3 billion megaproject was mired in planning delays for several years before construction began in 2011 with the partial demolition of the viaduct. The tunnel was constructed using Bertha, the world's largest tunnel boring machine at the time of its launch in 2013, which had a two-year halt and completed its bore in 2017. The viaduct was demolished in 2019, leaving room for an expanded park promenade on Alaskan Way that is planned to be completed in 2024.
- ^ Multimodal Planning Division (February 4, 2020). State Highway Log Planning Report 2019, SR 2 to SR 971 (PDF) (Report). Washington State Department of Transportation. pp. 771–803. Retrieved May 16, 2020.