A new section of the Interstate 5 interchange in DuPont is expected to open in mid-January, pending weather conditions. The upgrade includes a new roundabout and supports the broader I-5 corridor improvement project scheduled for completion in late 2026, according to the Washington State Department of Transportation.
The opening of exit 119 to Steilacoom-DuPont Road will change traffic patterns, directing DuPont-bound drivers to a new roundabout and JBLM-bound traffic over a new overpass. Once open, the new overpass will handle traffic from DuPont to JBLM and northbound I-5, while the older overpass will be limited to traffic from JBLM to DuPont or southbound I-5, as reported by the Washington State Department of Transportation.
The new overpass is scheduled to open by spring 2026 with two-way traffic using a diverging diamond interchange, along with new pedestrian and bicycle connections between DuPont and Joint Base Lewis-McChord. The current overpass will be demolished before then, which will require overnight lane closures that Washington State Department of Transportation will announce later. The project is expected to finish in late summer 2026 with new HOV lanes opening between Mounts Road and Gravelly Lake Drive. The work is part of a $240 million I-5 Mounts Road to Thorne Lake Corridor Improvements project that has already added HOV and auxiliary lanes and updated nearby interchanges.
