WSDOT is in the process of completing two Environmental Assessments for the upcoming I-405 Renton to Bellevue Widening and Express Toll Lanes construction contract.

I-405 - Downtown Bellevue Vicinity Express Toll Lanes Project (spring 2018)

WSDOT published the EA for this segment on April 2, 2018 and the Finding of No Significant Impact (FONSI) and Errata (pdf 17.58 mb) on July 17, 2018.

• Project overview and context
• Summary of Environmental Assessment findings
• Download the Environmental Assessment and other documentation

I-405, Tukwila to I-90 Vicinity Express Toll Lanes Project (summer 2018) 

WSDOT published the EA for this segment on July 5, 2018 and the Finding of No Significant Impact (FONSI) and Errata (pdf 36.66 mb) on April 12, 2019.

• Project overview and context
• Summary of Environmental Assessment findings (Information in Español - Spanish)
• Download the Environmental Assessment and discipline reports

What is an Environmental Assessment? 

In compliance with the National Environmental Policy Act (NEPA), the Environmental Assessment describes the purpose and need of the project and provides information to the public and decision makers about environmental effects and benefits of the project.

In this case, the EA compares future effects if WSDOT did or did not build the project, and provides a detailed analysis of the proposed project’s effects, including traffic, social and community effects, stormwater and ecosystems.

What topics did WSDOT study in the Environmental Assessment?

• Transportation
• Air quality
• Noise
• Environmental justice
• Geology and soils
• Visual quality
• Water resources
• Ecosystems
• Hazardous materials
• Energy and greenhouse gases
• Historic, cultural, and archaeological resources
• Parks and recreation lands