I-5 Mounts Road to Thorne Ln I/C - Corridor Improvements - Project map

map showing proposed elements of the I-5 - Mounts Road to Thorne Lane I/C Corridor Improvements project

The above vicinity map shows the four stages of construction of the I-5 - Mounts Road to Thorne Lane I/C Corridor Improvements project. 

  • Stage 1: I-5 - Mounts Road to Center Drive - Auxiliary Lane Extension - construction began in spring of 2017. Northbound I-5 was widened between Mounts Road and Center Drive for an auxiliary lane. The new extended auxiliary lane opened to traffic in Nov. 2017. Final striping will occur in spring 2018. In later stages of construction, this lane will be converted into a general purpose lane.
  • Stage 2: I-5 – Steilacoom –DuPont Rd. to Thorne Lane – WSDOT is in the process of selecting a design-builder for this project. The design build contract will begin mid-2018. This project will rebuild the Thorne Lane and Berkeley Street interchanges, and add a fourth lane to I-5 in each direction from Thorne Lane to just past JBLM's main gate.
  • Stage 3: I-5 – Mounts Road to Steilacoom-DuPont Road project - scheduled to begin in 2021. This project will build improvements between Mounts Road (Exit 116) and Steilacoom-DuPont Road (Exit 119). Improvements to the Steilacoom-DuPont Road interchange are being finalized. 
  • Stage 4: Gravelly-Thorne Connector and Shared-Use path. Next steps for this design-build project include a compatibility report, right-of-way acquisition and a competitive bidding process. Project construction will then occur beginning 2022.