An Interstate 5 traffic shift was rained out over the weekend and has been rescheduled for overnight Wednesday and Thursday, according to Washington State Department of Transportation officials. Backups are expected Thursday night and Friday morning on southbound I-5 near the Tacoma Dome due to a triple-lane closure and rolling slowdowns. Drivers are advised to consider alternate routes and to use extra caution through the winding work zone.

Straightening out the southbound S-curves Thursday night — weather permitting — will keep the project on schedule to shift northbound traffic this coming weekend, and complete girder-setting work for two new bridges over the freeway.

However, doing this work on a weekday creates the potential for major backups Thursday night and Friday morning.

Work to shift southbound I-5 back to its regular configuration begins tonight, as crews realign the I-705 ramp to southbound I-5. This work requires closing the ramp and the right southbound lane Tuesday and Wednesday from 10 p.m. to 6 a.m.; and closing the ramp and three southbound lanes overnight Thursday, 9 p.m. to 5 a.m.

Ironing out the northbound S-curves overnight Saturday requires closing the SR 16 ramp to northbound I-5 and two northbound lanes, starting at 9 p.m. The ramp and lanes will reopen by 10 a.m., Sunday.

Without the curves, the regular speed limit returns, lanes and shoulders widen, and traffic flow should improve due to a longer merging area on southbound I-5 between I-705 and SR 16.

The S-curve configuration on this busy stretch of highway allowed workers to demolish three bridges and set steel girders for two new overpasses. Moving traffic back to regular lanes gives workers — and a 300-ton hydraulic crane — work space to set the final eight girders for the Yakima Avenue and Delin Street bridges. That work resumes Monday, weather permitting.

The new bridges are part of the I-5 HOV Improvements, 48th Street to Pacific Avenue project, which creates space for future HOV lanes and increases safety by building northbound collector-distributor lanes that reduce the weaving traffic at the State Route 16 curve. The new overpasses open to traffic in March and the project wraps up next spring.