People who rely on northbound Interstate 5 through downtown Seattle should plan for overnight closures on Wednesday, March 20 and Monday, March 25.

Contractor crews working for the Washington State Department of Transportation (WSDOT) will close the I-5 mainline and the collector/distributor lanes from I-90 to Olive Way between 11:59 p.m. Wednesday, March 20, and 4 a.m. Thursday, March 21. The same closure will be in place from 11:59 p.m. Monday, March 25, until 4 a.m. Tuesday, March 26. The closure will allow crews to install a sign bridge and an electronic sign as part of a project designed to improve mobility on I-5 through downtown Seattle.

On both dates, lane reductions will begin on mainline I-5 at 9 p.m. with the collector/distributor lanes also closing at 11:59 p.m.

People traveling to downtown Seattle on I-5 from the south should use the Edgar Martinez Drive exit or take eastbound I-90 and exit at Rainier Avenue. The off-ramps to James, Madison and Cherry streets will be closed. The Cherry and University street on-ramps to northbound I-5 will also be closed.

Travelers going north of downtown can use the express lanes, keeping in mind the first exit is Northeast 42nd Street in the University District. The express lanes also have exits to Lake City Way and Northgate before rejoining the mainline.

For the latest construction closure information, visit the WSDOTreal-time travel map , download the WSDOT traffic app or sign up for email updates .