Drivers across the Puget Sound should prepare for one of the busiest travel weekends of the summer as multiple major highway construction projects, ongoing bridge rehabilitation work and several large Seattle events overlap from Friday through Monday.
The Washington State Department of Transportation (WSDOT) is warning travelers to expect significant delays on Interstate 405, Interstate 5, State Route 520 and State Route 202 near Fall City. At the same time, thousands of people are expected to head to Seattle for the Mariners’ 50 Seasons Celebration, Seahawks Football Fest and Capitol Hill Block Party, while the Fred Hutch Obliteride will bring cyclists to roads throughout the region.
HEADS UP: One of the busiest construction weekends of the summer is here!
— WSDOT Traffic (@wsdot_traffic) August 4, 2026
Major travel impacts include NB I-405, NE 85th St, EB SR 520 and SR 202 closures, plus NB I-5 lane reductions.
Plan ahead, follow detours and check our app or real-time travel map before you go. pic.twitter.com/olCnh8uNs1
WSDOT noted the construction comes during an extraordinarily difficult week for Washington as crews also continue responding to devastating wildfires in Central and Eastern Washington. The agency says it will continue providing updates on both wildfire-related road closures and major construction projects statewide.
Northbound I-405 closes between Renton and Bellevue
One of the largest closures of the weekend begins at 11:30 p.m. Friday, when northbound I-405 will close between SR 900/North Southport Drive-Northeast Sunset Boulevard and Coal Creek Parkway Southeast. The closure remains in place until 4 a.m. Monday.
The work is part of the I-405 Renton Bellevue Widening Project. Crews will replace aging pavement and excavate drainage crossings while the freeway is closed.
Drivers traveling north should detour using SR 900 east to Duvall Avenue and Coal Creek Parkway Southeast before reconnecting with I-405.
Kirkland ramps and NE 85th Street closed all weekend
Motorists traveling farther north on I-405 will also come across another closure in Kirkland.
Beginning at 10 p.m. Friday, the northbound and southbound I-405 Exit 18 off-ramps and the NE 85th Street on-ramps to both directions of I-405 will close until 5 a.m. Monday.
In addition, NE 85th Street between 6th Street and 114th Avenue Northeast will be closed while crews pave and stripe the roadway as part of the ongoing interchange improvements.
Eastbound SR 520 closure near Montlake
Drivers heading across Lake Washington Saturday evening should be aware of a temporary closure near Seattle.
From 7 p.m. Saturday until 11 a.m. Sunday, eastbound SR 520 will close between Interstate 5 and Montlake Boulevard while crews repair an expansion joint on the floating bridge approach.
The closure affects only the Seattle approach to SR 520. Eastbound traffic across Lake Washington will remain open.
Drivers coming from I-5 who normally use eastbound SR 520 should expect detours and additional congestion. WSDOT says eastbound I-90 will likely see heavier traffic because of the closure, although that route will also be impacted by several major events in Seattle Saturday evening.
Alternative routes include using local surface streets through Capitol Hill or the University District.
SR 202 closure continues near Fall City
State Route 202 will remain closed just east of the SR 202/203 roundabout near Fall City from 5 a.m. Friday through 9 p.m. Monday.
The closure allows crews to continue rebuilding the Snoqualmie River bank after severe storms in December 2025 and March 2026 eroded the hillside supporting the highway. The project is designed to stabilize the riverbank and better protect the roadway from future flooding.
Signed detours direct drivers to use Interstate 90.
People planning to float the Snoqualmie or Raging rivers this weekend should also expect temporary closures on portions of both rivers and nearby public access points while construction continues.
Revive I-5 work continues
Construction also continues on the Revive I-5 project over Seattle’s Ship Canal Bridge.
The express lanes remain operating northbound around the clock while rehabilitation work continues.
Saturday expected to be busiest travel day
Transportation officials expect Saturday to bring the heaviest traffic of the weekend.
The Mariners’ 50 Seasons Celebration at T-Mobile Park, Seahawks Football Fest at Lumen Field and Capitol Hill Block Party are expected to draw large crowds into Seattle. Combined with the eastbound SR 520 closure beginning Saturday evening, drivers should expect significant backups, especially on eastbound I-90 and surrounding city streets.
WSDOT encourages travelers to allow extra time, plan alternate routes before leaving home and drive cautiously through active work zones and around bicyclists throughout the weekend.
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