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, and was complete in 2018. Northbound I-5 was widened between Mounts Road and Center Drive for an auxiliary lane. 
  • Stage 2: I-5 – Steilacoom –DuPont Rd. to Thorne Lane – The design build contract will began mid-2018, and will finish in summer 2021. This project rebuilds the Thorne Lane and Berkeley Street interchanges, adds auxiliary lanes, and adds a fourth lane to I-5 in each direction from Thorne Lane to just past JBLM's main gate. The fourth lanes will operate as HOV lanes once construction is complete.
  • Stage 3: I-5 – Mounts Road to Steilacoom-DuPont Road project - scheduled to begin in 2022. 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 project include right-of-way acquisition, final design and a competitive bidding process. Project construction will then occur beginning 2023.