I-5 - Mounts Road to Thorne Ln I/C - Corridor Improvements - 2020 Supplemental Environmental Assessment

On June 30, 2021, the U.S. Department of Transportation Federal Highway Administration issued a Finding Of No Significant Impact (FONSI) for the Interstate 5 JBLM Congestion Relief Project Revised Environmental Assessment (pdf 31 mb).

WSDOT has published the I-5 JBLM Vicinity Congestion Relief - South Study Area Supplemental Environmental Assessment (pdf 61.84 mb).

This document was prepared as a supplement to the 2017 Environmental Assessment (EA) for the project's North Study Area. The Supplemental Environmental Assessment (SEA) describes the South Study Area and cover the potential environmental effects related to transportation, noise, natural resources, parks and recreation, community resources, and other resources. 

  • The South Study area is located between the vicinity of the Mounts Road (116) and Main Gate (120) exits.
  • The North Study Area is located between the Steilacoom-DuPont Road (119) and Thorne Lane (123) exits.
  • The North Study Area and South Study area overlap between Exits 119 and 120.

This SEA analyzes project-specific impacts in the South Study Area and operation of a High Occupancy Vehicle (HOV) lane in each direction through the complete study area (North and South).

An online open house was held Nov. 16 to Dec. 16, 2020, giving the public the opportunity to comment on the SEA.