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WSDOT set to partially open new I-5 interchange, roundabout near JBLM

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Published  January 21, 2026 12:07pm PST
WSDOT
FOX 13 Seattle

The Brief

    • The Washington State Department of Transportation plans to partially open a new southbound Interstate 5 interchange at Steilacoom-DuPont Road and a new roundabout this Saturday, Jan. 24. 
    • To prepare for the opening, crews have scheduled nightly lane and ramp closures near Joint Base Lewis-McChord through Friday. 
    • The $240 million project is expected to be fully completed by late 2026, featuring a diverging diamond interchange and extended HOV lanes.

DUPONT, Wash. - State transportation officials are preparing to partially open a new interchange and roundabout near Joint Base Lewis-McChord this weekend.

Weather permitting, the Washington State Department of Transportation (WSDOT) will partially open the new southbound Interstate 5 interchange at Exit 119/ Steilacoom-DuPont Road and the remainder of a new roundabout in DuPont on Saturday, Jan. 24.

The work is part of a multi-year effort to rebuild the Steilacoom-DuPont Road interchange and extend high-occupancy vehicle lanes to Mounts Road. WSDOT officials said the project is designed to improve mobility and alleviate chronic traffic delays near the military base. 

Here's what to expect:

Beginning Saturday morning, weather permitting, southbound I-5 exit 119 to Steilacoom-DuPont Road will reopen. 

Drivers will start using the new southbound I-5 exit to Steilacoom-DuPont Road to get to JBLM or northbound I-5. 

Anyone traveling to DuPont will turn right toward the new roundabout, and people traveling to JBLM will turn left and drive o nthe overpasss. 

Northbound travelers will continue to use the existing exit and the 1957 Steilacoom-DuPont overpass. 
 

(Washington State Department of Transportation)

Nightly closures this week

In preparation for the Saturday opening, WSDOT has scheduled several overnight closures:

  • Wednesday to Friday, Jan. 21-23Steilacoom-DuPont Road: Both directions approaching the roundabout will close nightly from 9 p.m. to 5 a.m., Wednesday, Jan. 21, through Friday, Jan. 23.
  • Steilacoom-DuPont Road: Both directions approaching the roundabout will close nightly from 9 p.m. to 5 a.m., Wednesday, Jan. 21, through Friday, Jan. 23.
  • Wednesday, Jan. 217 p.m. to 4:30 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road will close.7:30 p.m. to 4:30 a.m. – A single lane of northbound I-5 will close.8 p.m. to 4:30 a.m. – A single lane of southbound I-5 will close.
  • 7 p.m. to 4:30 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road will close.
  • 7:30 p.m. to 4:30 a.m. – A single lane of northbound I-5 will close.
  • 8 p.m. to 4:30 a.m. – A single lane of southbound I-5 will close.
  • Thursday, Jan. 227 p.m. to 4:30 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road (exit 119) will close.7:30 p.m. to 4:30 a.m. – A single lane of northbound I-5 will close.8 p.m. to 4:30 a.m. – Southbound I-5 exit to Steilacoom-DuPont Road (exit 119) will close.8 p.m. to 4:30 a.m. – A single lane of southbound I-5 will close.
  • 7 p.m. to 4:30 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road (exit 119) will close.
  • 7:30 p.m. to 4:30 a.m. – A single lane of northbound I-5 will close.
  • 8 p.m. to 4:30 a.m. – Southbound I-5 exit to Steilacoom-DuPont Road (exit 119) will close.
  • 8 p.m. to 4:30 a.m. – A single lane of southbound I-5 will close.
  • Friday, Jan. 238 p.m. to 6 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road (exit 119) will close.8 p.m. to 8 a.m. – A single lane of northbound I-5 will close.9 p.m. to 6:30 a.m. – Southbound I-5 off-ramp to Steilacoom-DuPont Road (exit 119) will close.9:30 p.m. to 8 a.m. – Up to two lanes of southbound I-5 will close.
  • 8 p.m. to 6 a.m. – Northbound I-5 off- and on-ramps at Steilacoom-DuPont Road (exit 119) will close.
  • 8 p.m. to 8 a.m. – A single lane of northbound I-5 will close.
  • 9 p.m. to 6:30 a.m. – Southbound I-5 off-ramp to Steilacoom-DuPont Road (exit 119) will close.
  • 9:30 p.m. to 8 a.m. – Up to two lanes of southbound I-5 will close.

What's next:

WSDOT expects to finish the project by late 2026. In the spring of that year, the overpass will fully transition into a "diverging diamond" interchange, a design intended to move traffic more efficiently.

Once the new structure is fully operational, crews will demolish the 1950s-era overpass, which is currently in poor condition and fails to meet modern height clearance standards. The demolition will clear the way for new HOV lanes, which are slated to open in late summer 2026.

The project is the latest phase of a broader corridor improvement plan that has already seen the reconstruction of the Berkeley Street and Thorne Lane interchanges.

The Source: Information in this story came from the Washington State Department of Transportation. 

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