TagSEPA(293)

This document is the References section of the Draft Environmental Impact Statement (EIS) for Seattle-Tacoma International Airport's Sustainable Airport Master Plan Near-Term Projects, published in May 2026 under Washington State's Environmental Policy Act (SEPA). It lists the sources cited across the EIS's chapters, covering topics such as aviation activity forecasts, terminal facility requirements, air quality standards, greenhouse gas emissions, geological surveys, and federal FAA design guidelines. The references draw from federal agencies (FAA, EPA), state bodies (WSDE, WDNR, WDFW), regional organizations (Puget Sound Regional Council), and consulting firms that informed the airport's environmental review and planning process.

This draft Environmental Impact Statement (EIS) evaluates proposed expansion projects at Seattle-Tacoma International Airport under Washington State's Environmental Policy Act (SEPA). It outlines a two-step screening process used to assess alternatives, including suggestions from public scoping such as building a new airport, using other transportation modes, and limiting growth — most of which were rejected for failing to meet the project's purpose of serving 56 million annual passengers at an optimal level of service. A No Action Alternative is also included, representing a future baseline without the proposed physical improvements.

This appendix outlines the traffic mitigation measures required for the Seattle-Tacoma International Airport Sustainable Airport Master Plan Near-Term Projects, as mandated by the FAA's Record of Decision and the Port of Seattle's State Environmental Policy Act Environmental Impact Statement. It details specific intersection improvements across multiple jurisdictions—including the City of SeaTac, City of Burien, City of Des Moines, and WSDOT—such as new traffic signals, roundabouts, and turn lane additions, along with proportionate-share cost contributions where full mitigation is not required. The measures are designed to address projected traffic impacts through 2037 and maintain acceptable levels of service at affected intersections near the airport.

This section of the Draft Environmental Impact Statement (EIS) for Seattle-Tacoma International Airport's Sustainable Airport Master Plan describes the existing environment surrounding the airport, which sits on approximately 2,800 acres in SeaTac, Washington, about 12 miles south of downtown Seattle. The study area covers roughly 3,692 acres bounded by nearby cities including Burien, Des Moines, and Tukwila, where surrounding land use is primarily residential, commercial, and parkland. Baseline environmental conditions are drawn from 2022 data to assess potential direct and indirect impacts of proposed near-term airport development alternatives.

This appendix lists the individuals and organizations responsible for preparing the environmental review documents for Seattle-Tacoma International Airport's Sustainable Airport Master Plan Near-Term Projects. It includes two tables: one covering contributors to the State Environmental Policy Act (SEPA) Environmental Impact Statement, and one listing those who prepared the National Environmental Policy Act (NEPA) Environmental Assessment. Key contributors include staff from the Port of Seattle, consulting firms such as Parametrix, Landrum & Brown, CDM Smith, Concord Engineering, and RS&H, covering areas such as air quality, noise, climate change, safety, and biological resources.

This report analyzes existing traffic conditions around Seattle-Tacoma International Airport as part of the Sustainable Airport Master Plan (SAMP) Near-Term Projects Environmental Review. It examines 108 intersections—including signalized, stop-controlled, and uncontrolled locations—along key travel routes connecting the airport to surrounding communities, focusing on weekday PM peak hour traffic volumes. The study also includes freeway analysis of SR 518 and I-5 ramps and segments at the request of WSDOT.