TagSR509(108)

The Washington State Department of Transportation (WSDOT) presented the Puget Sound Gateway Program to the Highline Forum in November 2020, outlining plans to complete SR 509 in King County and SR 167 in Pierce County. The SR 509 project includes creating a new south access point to Sea-Tac Airport, improving freight connections to the ports of Seattle and Tacoma, and reducing congestion on local roads. The program also proposes tolling as a tool for sustainable congestion management.

This 2019 WSDOT report analyzes noise barriers along the SR509 Phase 1 highway alignment near the Sea-Tac area, evaluating whether proposed sound walls meet feasibility and cost-reasonableness standards. Wall 3 was rejected because it could not achieve the required 5 dB noise reduction for nearby residents. Wall 4 met the technical noise-reduction threshold but was ultimately rejected because its estimated cost of $111,478 exceeded the allowable budget of $72,254.

The Puget Sound Gateway Program, presented at a Highline Forum in September 2018, outlines two highway completion projects—SR 509 in King County and SR 167 in Pierce County—designed to improve freight movement between the ports of Seattle and Tacoma and key distribution centers. Among its key benefits, the program includes a new south access point to Sea-Tac Airport and aims to reduce congestion on local roads surrounding the airport. Funding for the program combines state, local, federal, and toll revenue sources, with electronic tolling on all new lanes expected to begin as early as 2025.

The City of SeaTac entered into an interlocal agreement (Agreement No. 18-A144) with the Washington State Department of Transportation (WSDOT) to provide up to $4,000,000 in local matching funds for the construction of the Puget Sound Gateway Program, specifically the State Route 509 Extension Project. The funding is split into two stages: up to $2,000,000 in real estate and/or cash for the SeaTac Access Local Nexus Project, and up to $2,000,000 in cash toward the South 188th Street Interchange once construction sales tax is received. WSDOT is responsible for designing, constructing, and managing the project, which includes improvements such as interchange ramps and access roads largely within the City of SeaTac.

This January 2018 environmental re-evaluation examines the potential impacts of Phase 1 of the SR 509 Completion Project, part of the Puget Sound Gateway Program, prepared for the Federal Highway Administration and Washington State Department of Transportation. The document assesses changed conditions and effects across multiple environmental categories—including noise, air quality, water quality, wetlands, and transportation—comparing the current project phase against the 2003 Final Environmental Impact Statement's preferred alternative. Notably, the noise section evaluates both operational and construction-phase sound impacts on surrounding communities, making it a relevant reference for research into transportation-related noise policy near Sea-Tac Airport.

This aerial map depicts Seattle-Tacoma International Airport (Sea-Tac) and its surrounding communities of Burien and SeaTac, showing the airport's runway layout including runways 34L and 34C, along with the local road network and key routes such as SR 99 and SR 509. The map highlights the ST Light Rail corridor and major access roads serving the airport, providing geographic context for understanding flight paths and noise exposure areas in the region. It serves as a reference for analyzing the relationship between airport operations and the residential and commercial areas situated beneath approach and departure corridors.