From a WSDOT press release:

Drivers who use the southbound Interstate 405 ramp to southbound State Route 167/Rainier Avenue South should prepare for a new configuration starting as soon as Saturday morning, March 17.

Overnight Friday, March 16, construction crews working for the Washington State Department of Transportation plan to complete striping work to move the southbound I-405 off-ramp to southbound SR 167/Rainier Avenue South farther to the right side of the roadway. In addition, the location where drivers must decide whether to take this exit will be approximately 400 feet sooner than it is today, just to the north of the Benson Road South overpass on southbound I-405. The same number of lanes will remain in place after the shift is complete.

This traffic change is necessary to provide crews enough space to create a new construction work zone. They will use this area to continue building the future flyover ramp for the I-405/SR 167 Interchange Direct Connector Project.

This work requires lane and ramp closures in both directions near the I-405/SR 167 interchange. The construction activities are weather dependent and subject to change. If crews cannot complete the workFriday night, they will postpone their work to the next dry night.

Lane closures:

• Friday, March 16, to the morning of Saturday, March 17 – Up to two lanes of southbound I-405 between Talbot Road South and SR 167 will be closed from 11 p.m. to 6 a.m.

Ramp closures:

• Friday, March 16, to the morning of Saturday, March 17 – The southbound I-405 ramp to southbound SR 167/Rainier Avenue South will be closed from 10 p.m. to 6 a.m. A signed detour will be in place.