Several major highway constructions will overlap this weekend, including a full closure of I-405.
The Washington State Department of Transportation (WSDOT) said travelers should expect closures and delays on several key routes from Friday, Aug. 7 through Monday, Aug. 10 on I-405, SR-520, I-5 and SR-202.
Northbound I-405 will fully close from North Southport Drive/Northeast Sunset Boulevard to Coal Creek Parkway Southeast from 11:30 p.m. Friday, Aug. 7 to 4 a.m. Monday, Aug. 10. Travelers can expect heavy congestion on the interstate approaching Renton. A signed detour will be in place.
Crews will excavate drainage crossings and complete full pavement replacements and a traffic switch on northbound I-405 as part of the I-405/Renton to Bellevue Widening and Express Toll Lanes Project.
Eastbound SR 520 will experience an overnight closure between I-5 and Montlake Boulevard from 7 p.m. Saturday, Aug. 8 to 11 a.m. Sunday, Aug. 9. All traffic from I-5 heading to eastbound SR 520 must use alternate routes. Eastbound SR 520 is open across Lake Washington. Only the section of eastbound SR 520 between I-5 and Montlake Boulevard will close.
Northbound I-5 will be reduced to two lanes in Seattle across the Ship Canal Bridge until the end of 2026. The express lanes will remain open northbound-only 24 hours a day. The Harvard Avenue on-ramp to northbound I-5 is closed until mid-October.
SR 202 east of the SR 202/SR 203 roundabout will close from 9 p.m. Thursday, Aug. 6 to 9 p.m. Monday, Aug. 10. Signed detours will help guide people around the closure via I-90, but may add 45 minutes or more to travel times. The closure is to rebuild the road embankment along the Snoqualmie River at milepost 22.
Portions of the Snoqualmie and Raging rivers may be closed during in-water construction work while construction vehicles and cranes are used to repair the riverbank. Public river access and nearby boat launches may also be affected during this work.
“Travelers should expect longer and less predictable trips,” WSDOT said. “Delays may occur in new places and at new times, and conditions may change week to week as work moves around the region.”
