Anyone who’s driven from Pierce County to Portland for a weekend knows the trip home Sunday can be a slog, especially that last stretch of Interstate 5 from Lacey to DuPont.
Just this past Monday, heavy traffic dogged the 10-mile section of northbound I-5 between Olympia and Mounts Road for five hours as Presidents Day holiday travelers returned from points south.
Workdays aren’t much better, with an average of 59,000 vehicles a day traveling north between Mounts Road and Steilacoom-DuPont Road, according to state Department of Transportation traffic counts.
“Traffic volumes on I-5 between Mounts Road and Steilacoom-DuPont Road have increased substantially over the past 10 years,” said John Wynands, a regional administrator for the Transportation Department.
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Help is on the way.
Crews began work this month to add a northbound lane between Mounts Road and Steilacoom-DuPont Road.
The so-called “auxiliary lane” will run 1.5 miles.
Auxiliary lanes are used between closely spaced interchanges to give traffic getting on and off the interstate more space to maneuver.
They’re also a place for trucks slowed by an uphill grade to leave the main flow of traffic.
Transportation Department officials say the new lane between Mounts and Steilacoom-DuPont will provide such relief.
“The lengthened auxiliary lane will increase the number of northbound I-5 lanes from three to four between the two ramps, giving drivers and trucks approaching the weigh station more room to merge on and off I-5 along an uphill grade,” spokeswoman Cara Mitchell wrote in a news release.
Eventually, the new lane will tie in with a much bigger improvement project between Mounts Road and Thorne Lane, Mitchell added.
That $494 million project will expand and improve I-5 along Joint Base Lewis-McChord, including widening the freeway in both directions and rebuilding the Berkeley Street and Thorne Lane interchanges.
Construction on that project could start next year.
In the meantime, workers have been temporarily closing northbound and southbound lanes to create a safe work zone in the highway median for the new auxiliary lane project, Mitchell said. Much of that work has taken place at night.
The pace is expected to pick up next month.
“During construction, drivers can anticipate narrowed and shifted lanes with overnight lane and ramp closures,” according to the news release. “Bicyclists who use northbound I-5 between Center Drive and Steilacoom-DuPont Road are advised to follow the signed detour through DuPont.”
The project is expected to cost about $11 million and be wrapped up by fall.