The Washington State Department of Transportation (WSDOT) has announced a major construction effort for the weekend, which they are calling “Monster Weekend.”
Several key highways in the Seattle/Tacoma region will be closed or partially shut down from Friday, September 27, through Monday, September 30, to complete important projects before the summer construction season ends.
The closures include major routes like SR 520, I-405, SR 167, and I-5. Some closures last the entire weekend, and others occur only overnight.
Drivers are advised to expect detours, delays, and significant traffic impacts.
SR 520: The highway and trail will be closed between I-5 in Seattle and 92nd Avenue Northeast in Clyde Hill starting at 11 p.m. on Friday, September 27, until 5 a.m. on Monday, September 30. Crews will be working on lighting and the fire suppression system under the new Montlake lid.
I-405 in Renton: Northbound lanes will be closed between Sunset Boulevard Northeast/Southport Drive (Exit 5) and Coal Creek Parkway Southeast from 11 p.m. on Friday to 4 a.m. on Monday. A detour will be available, but this work is weather-dependent and may be rescheduled.
SR 167 in Kent: Southbound lanes will be closed between SR 516 and South 27th Street starting at 11:59 p.m. on Friday through 4 a.m. Monday for paving and striping work, also subject to weather conditions.
I-5 (Federal Way to Fife): Overnight closures will affect both northbound and southbound lanes between SR 18 and 54th Avenue East. Northbound lanes will close by 10:30 p.m. Friday and southbound lanes by 11 p.m. Closures will last until 7 a.m. on Saturday and 8 a.m. on Sunday, with full reopening by noon each day. Crews will be setting girders for a new overpass.
Mercer Street on-ramps to I-5: The on-ramps to both northbound and southbound I-5 from Mercer Street in Seattle will be closed for paving and shoulder work starting at 10 p.m. Friday and lasting until 5 a.m. Monday.
WSDOT advises drivers to plan ahead and use alternate routes or travel during off-peak hours, as detour routes will likely experience significant congestion.
The department also encourages travelers to check the real-time traffic map for updates.