Project overview
This project is intended to help relieve chronic traffic congestion and improve mobility along I-5 near Joint Base Lewis-McChord. Crews will rebuild the Steilacoom-DuPont Road (Exit 119) interchange and extend I-5 HOV lanes to Mounts Road.
What to expect
I-5 work
Crews have created a new work zone in the I-5 median. The new work zone allows crews to build new northbound and southbound I-5 HOV lanes.
Work also continues on a new I-5 bridge over Pendleton Avenue. Crews will continue building a new Steilacoom-DuPont Road interchange and a connecting roundabout from Steilacoom-DuPont Road.
I-5 HOV lane changes
Southbound HOV
People traveling on southbound I-5 near 41st Division Drive may notice changes to the HOV lane. The contractor restriped a 750-foot-long section to create more room for drivers to merge from the 41st Division Drive on-ramp. This will help ease congestion approaching DuPont and JBLM exits.
Northbound HOV
Crews opened a portion of the new northbound I-5 HOV lane in summer 2025. The addition runs from Pendleton Avenue to JBLM Main Gate. The remaining new northbound and southbound HOV lanes will open during 2026.
I-5 lane closures
Travelers can expect nighttime lane reductions on both directions of I-5. Crews will begin reducing lanes as early at 7 p.m. each Monday through Thursday night between Center Drive and 41st Division Drive. All lanes should reopen to traffic by 4:30 a.m. the following morning.
Ramp closures
Ramps will close no earlier than 7 p.m. and will reopen by 4:30 a.m. the next morning. No more than two consecutive ramps will close at a time. A signed detour will direct drivers to the next nearest on- or off-ramp.
Temporary changes to southbound I-5 exit 119/Steilacoom-DuPont Road
The southbound I-5 exit to Steilacoom-DuPont Road has been temporarily relocated. It is located between the new and existing Steilacoom-DuPont Road overpass. The exit will remain in this location until early 2026.
The temporary changes allow crews to continue construction of the new Steilacoom-DuPont Road interchange.
Mounts Road
A new traffic signal replaces an all-way stop on the southbound I-5 exit to Mounts Road. The traffic signal was activated in July 2025.
The project will add HOV lanes to both directions of I-5.
Crews will rebuild the Steilacoom-DuPont Road interchange. The new interchange will connect to Steilacoom-DuPont Road near Pendleton Avenue. Workers will replace the existing at-grade railroad crossing. Crews will build a new bridge. It will carry travelers over the tracks.
This project is the third in a series of projects that widen I-5. The work creates new HOV lanes. After this project is complete, both directions of I-5 will have HOV lanes between Mounts Road and Gravelly Lake Drive.
New overpasses are necessary to add lanes. This is the case for the existing overpass at the Steilacoom-DuPont Road interchange.
The existing overpass was built in 1957. It is classified as "poor condition". It does not meet current vertical clearance standards from I-5.
A new interchange will be built to current design standards and allow for new HOV lanes in both directions of I-5.
Traffic flow is slowed due to the current distance between each interchange. Other factors include JBLM’s DuPont Gate, the railroad, and the intersection of Wilmington Drive and Barksdale Avenue.
Environment
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 31MB).
WSDOT has published the I-5 JBLM Vicinity Congestion Relief - South Study Area Supplemental Environmental Assessment (PDF 61.84MB).
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.
For links to the 2017 EA, please refer to the Environment tab on the I-5 - Mounts Road to Thorne Lane I/C - Corridor Improvements webpage.
