Birth of an interchange continues in DuPont

2026 is going to be a good year for I-5 drivers through DuPont. The new interchange at the Stelicoom-DuPont Road will open this year, providing better access to the city and JBLM.

Drivers should get their crack at part of the new interchange later this month.

The Washington State Department of Transportation (WSDOT) is expecting to open the new I-5 southbound access to the new interchange by the middle of January.

“This is a partial turn on for the interchange,” WSDOT spokesperson Doug Adamson said. “One of the benefits of this is that it helps us accelerate the construction schedule and get the work done. We’re on time. We’re on schedule with this.”

New roundabout opens for southbound drivers

The new roundabout, just north of the freeway, will also open at the same time. This is a new exit for southbound drivers. Drivers heading to DuPont will take a right to that new roundabout, and drivers heading to JBLM will take a left from the new exit.

Northbound drivers will continue to use the old exit and overpass, as will drivers from JBLM looking to access DuPont or southbound I-5.

“Later on this spring, we will fully open the new overpass and will have the demolition of the existing overpass,” Adamson said. “The removal of the old overpass will take several overnight closures of I-5. Those dates have not been released.”

The new overpass will also drop drivers off on the other side of the railroad tracks, eliminating backups and increasing safety.

The new HOV lanes between Gravelly Lake Drive and Mounts Road, which are part of this project, are expected to open over the summer. This is the final piece of construction that has added new overpasses and HOV lanes through JBLM over the last few years.

It has made the drive-through area better, but not without some pain.

“We understand fully that we are moving the bottleneck,” Adamson said. “Let’s have a reality check here. It will, however, have a significant improvement for people serving our country at Joint Base Lewis-McChord.”

Southbound I-5 will slim down to three lanes at Mounts Road after this work is finished, as Adamson said, pushing the congestion further south.

That will not disappear until WSDOT takes up the next piece of the puzzle, which is widening I-5 in both directions through Nisqually. That project requires new bridges over the Nisqually River. Initial work on that is just getting going, but that project is years away.

Chris Sullivan is a traffic reporter for KIRO Newsradio. Read more of his stories here. Follow KIRO Newsradio traffic on X.

Follow @https://twitter.com/newsguysully