Infrastructure

I-405 and SR 169 lane closures underway

Friday, August 21, 2026

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Starting Monday, August 17, multiple lane closures began on I-405 and SR 169 for construction work, with most ending Friday, August 21. The I-405 closures include nightly lane closures on both northbound and southbound lanes between mileposts 16.45 and 18.12, running from 11 p.m. to 4 a.m., and a closure of the northbound I-405 offramp to Northeast 85th Street from 11 p.m. to 5 a.m. nightly.

SR 169 in Black Diamond is closed for 35 days from August 17 through September 21 for fish barrier removal, with signed detours for passenger and freight vehicles. The closure allows local access but requires through traffic to follow detours. WSDOT's public records detail all affected routes, times, and durations with specific mileposts and dates.

WSDOT's construction schedule is available on their website, and residents are advised to plan travel around these closures for the duration of the work.

📄 Source: WSDOT — Highway Construction & Closures — https://wsdot.wa.gov/travel/road-construction

Source receipts10 of 18 claims supported · 56%

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Multiple lane closures began on I-405 and SR 169 starting Monday, August 17“405: Monday, August 17 to the morning of Friday, August 21: The northbound I-405 offramp to Northeast 85th Street will be closed, nightly from 11 p.m. - 5 a.m.”
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Most lane closures on I-405 and SR 169 ended Friday, August 21No usable supporting receipt — unverified.
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Nightly lane closures on I-405 northbound and southbound lanes between mileposts 16.45 and 18.12 started on Monday, August 17No usable supporting receipt — unverified.
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Nightly lane closures on I-405 northbound and southbound lanes between mileposts 16.45 and 18.12 ended on Friday, August 21No usable supporting receipt — unverified.
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Nightly lane closures on I-405 northbound and southbound lanes between mileposts 16.45 and 18.12 run from 11 p.m. to 4 a.m.No usable supporting receipt — unverified.
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The northbound I-405 offramp to Northeast 85th Street is closed nightly from 11 p.m. to 5 a.m.“405: Monday, August 17 to the morning of Friday, August 21: The northbound I-405 offramp to Northeast 85th Street will be closed, nightly from 11 p.m. - 5 a.m.”
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SR 169 in Black Diamond is closed for 35 days from August 17 through September 21“169: Starting Monday, Aug. 17, both directions of SR 169 in Black Diamond are closed between Southeast 332nd Street and Plass Road for 35 days for fish barrier removal. Separate signed detours will guide passenger vehicles and freight vehicles around the closure. Local access is permitted north and south of the closure, but through traffic must follow the signed detours. Businesses are open and accessible along SR 169 during this construction. Effective: Aug 5, 2026, 11:19 AM Expected end: Sep 21, 2026, 5:00 AM”
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SR 169 in Black Diamond is closed starting August 17“169: Starting Monday, Aug. 17, both directions of SR 169 in Black Diamond are closed between Southeast 332nd Street and Plass Road for 35 days for fish barrier removal.”
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SR 169 in Black Diamond is closed ending September 21“169: Starting Monday, Aug. 17, both directions of SR 169 in Black Diamond are closed between Southeast 332nd Street and Plass Road for 35 days for fish barrier removal. Separate signed detours will guide passenger vehicles and freight vehicles around the closure. Local access is permitted north and south of the closure, but through traffic must follow the signed detours. Businesses are open and accessible along SR 169 during this construction. Effective: Aug 5, 2026, 11:19 AM Expected end: Sep 21, 2026, 5:00 AM”
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SR 169 in Black Diamond is closed for fish barrier removal“169: Starting Monday, Aug. 17, both directions of SR 169 in Black Diamond are closed between Southeast 332nd Street and Plass Road for 35 days for fish barrier removal.”
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Signed detours for passenger and freight vehicles are in place for SR 169 in Black Diamond“Separate signed detours will guide passenger vehicles and freight vehicles around the closure.”
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Local access is allowed during SR 169 closure in Black Diamond“Local access is permitted north and south of the closure, but through traffic must follow the signed detours.”
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Through traffic must follow detours during SR 169 closure in Black Diamond“Separate signed detours will guide passenger vehicles and freight vehicles around the closure. Local access is permitted north and south of the closure, but through traffic must follow the signed detours. Businesses are open and accessible along SR 169 during this construction.”
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WSDOT's public records detail all affected routes, times, and durations for SR 169 closureNo usable supporting receipt — unverified.
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WSDOT's public records detail specific mileposts for SR 169 closureNo usable supporting receipt — unverified.
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WSDOT's public records detail specific dates for SR 169 closure“169: Starting Monday, Aug. 17, both directions of SR 169 in Black Diamond are closed between Southeast 332nd Street and Plass Road for 35 days for fish barrier removal. Separate signed detours will guide passenger vehicles and freight vehicles around the closure. Local access is permitted north and south of the closure, but through traffic must follow the signed detours. Businesses are open and accessible along SR 169 during this construction. Effective: Aug 5, 2026, 11:19 AM Expected end: Sep 21, 2026, 5:00 AM”
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WSDOT's construction schedule is available on their websiteNo usable supporting receipt — unverified.
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Residents are advised to plan travel around closures for the duration of the workNo usable supporting receipt — unverified.