A taller, wider and safer overpass and longer HOV lanes are coming soon to I-5 in DuPont
When a three-yearlong state Department of Transportation project is finished, Interstate 5 will have a taller, wider and safer overpass in DuPont and more miles of HOV lanes.
The $202 million project is expected to break ground in mid-August. It incorporates the new overpass to link Joint Base Lewis-McChord with DuPont while crossing high above railroad tracks that now carry passenger trains. Also on the to-do list: Extending those short sections of HOV lanes built in 2021 on both directions of I-5.
The work is all taking place between Mounts Road and Steilacoom-DuPont Road.
New overpass
The existing I-5/Steilacoom-DuPont Road overpass at milepost 119 will be torn down and rebuilt as a diverging diamond overpass. A diverging diamond overpass is in use at the Marvin Road and I-5 interchange in Thurston County.
The new bridge will pass high overhead railroad tracks that carry Amtrak regional and west coast lines. The bridge will have a shared use path for pedestrians and bicyclists.
A new roundabout will connect Steilacoom-DuPont Road and the overpass.
The existing 1957 bridge over I-5 is too narrow to add lanes and it’s classified as “poor condition,” according to WSDOT. It also does not meet current vertical clearance standards.
HOV lanes
The new overpass will allow for the road bed to be widened in order for WSDOT contractor Atkinson Construction to build HOV lanes underneath it.
The northbound HOV lane will be extended to 31/2 miles from Mounts Road (Exit 116) to where it currently begins just before 41st Division Drive at milepost 120. The lane currently ends at Gravelly Lake Drive.
The southbound HOV lane will be extended to 4 miles from its current end at 41st Division Drive (Exit 120) to the Steilacoom-DuPont interchange (Exit 119). It currently starts near the Thorne Lane and Berkeley Street exit.
The project will also add a northbound auxiliary lane on I-5 between Center Drive and Steilacoom-DuPont Road.
Construction
As crews from WSDOT contractor Atkinson Construction widen I-5, drivers will see shifted lanes, reduced speeds and overnight lane and ramp closures between exit 116 (Mounts Road), exit 118 (Center Drive) and exit 119 (Steilacoom-DuPont Road), WSDOT said.
In Washington state, interstate exits are numbered by miles traveled from a beginning point; in this case the Oregon state line. Therefore, Center Drive is 118 road miles north of Oregon. There is no exit 117.
There will be some overnight closures of I-5 for bridge demolition and new girder placement but those dates have yet to be scheduled, WSDOT said.
Phased construction
The $202 million project is the third in a series of projects that are widening I-5 to increase HOV miles.
Because some of the original overpasses dating to the 1950s are too narrow, they need to be replaced, WSDOT said.
Project funding was approved by the Washington State Legislature in the 2015 Connecting Washington transportation revenue package.