Construction to start soon on I-5 at Steilacoom-DuPont Road in DuPont

Project builds new overpass, extends HOV lanes in south Pierce County

DUPONT – This August, a major construction project will kick off in Pierce County that extends HOV lanes and builds a new overpass over Interstate 5 linking Joint Base Lewis-McChord and the city of DuPont.

Work on the I-5 Mounts Road to Steilacoom-DuPont Road Corridor Improvements project is focused at the I-5/Steilacoom-DuPont Road Interchange, at milepost 119.

Contractor crews working for the Washington State Department of Transportation will widen the interstate to extend the HOV lanes built in 2021.

The 3-year project also includes:

  • Building a new bridge spanning I-5 and the railroad. The new bridge will feature a diverging diamond interchange and a shared use path for pedestrians and bicyclists between JBLM and DuPont.
  • Adding a northbound I-5 auxiliary lane between Center Drive and Steilacoom-DuPont Road.
  • Building a new roundabout connecting Steilacoom-DuPont Road and the new overpass.
  • Installing a new signal at the intersection of the southbound I-5 off-ramp at Mounts Road.

What to expect during construction

During construction, travelers will see shifted lanes, reduced speeds and overnight lane and ramp closures at:

  • Mounts Road at exit 116, Center Drive at exit 118 and Steilacoom-DuPont Road at exit 119.
  • Some overnight closures of I-5 for bridge demolition and new girder placement.
  • Some weekend closures of the JBLM DuPont Gate.

Exact dates and overnight closure hours will be shared on the project webpage, social media and the WSDOT interactive travel map once finalized. Travelers on both directions of I-5 will see some delays during construction.

Please help keep road workers safe. When approaching a work zone, remember to:

  • Slow down – drive the posted speeds, they are there for your safety. 
  • Be kind – our workers are out there helping to keep you safe and improve the roadways. 
  • Pay attention – both to workers directing you and surrounding traffic; put your phone down when behind the wheel. 
  • Stay calm – expect delays, leave early or take an alternate route if possible; no meeting or appointment is worth risking someone’s life. 

About the project

This $202 million project is the third in a series that widens I-5 to build HOV lanes from Mounts Road near DuPont to Gravelly Lake Drive in Lakewood. At the completion of this project, cumulatively, the new larger overpasses at Steilacoom-DuPont Road, Berkeley Street and Thorne Lane will increase the overpass vertical clearance over I-5 to meet current design standards and eliminate three signalized at-grade railroad crossings.  

Funding for the project was approved by the Washington State Legislature in the 2015 Connecting Washington transportation revenue package. Guy F. Atkinson Construction crews are contracted for this work.

Real-time traveler information is available from the WSDOT app, and the WSDOT statewide travel map.

Slow down – lives are on the line. 

In 2023, speeding continued to be a top reason for work zone crashes.

Even one life lost is too many.

Fatal work zone crashes doubled in 2023 - Washington had 10 fatal work zone crashes on state roads.

It's in EVERYONE’S best interest.

95% of people hurt in work zones are drivers, their passengers or passing pedestrians, not just our road crews.