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I-405-sr 520 Nbcd over I-405 N-e & N-w Ramps

King County, Washington · rated Good in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I-405-sr 520 Nbcd over I-405 N-e & N-w Ramps in King County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 8 (very good condition) on the 0-9 scale.
It was built in 2011, making it 14 years old at the 2025 inventory.
It carries about 9,875 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 595 of the 1,252 inventoried bridges in King County rated good (47.5%); 50 (4.0%) are rated poor.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings


Structure	Continuous prestressed concrete stringer or multi-beam girder
Length	about 439 ft
Location	3.1 N Jct I-90
NBI structure number	0017726G0000000
Condition class	Good

Source: FHWA National Bridge Inventory, 2025 data as reported by the Washington department of transportation.

Bridge	Built	Vehicles/day	Condition
I-90 EB over Sunset Creek	2024	139,482	Good
I-90 WB over Sunset Creek	2024	139,482	Good
N Queen Anne Dr over Ravine	1935	125,000	Fair
I-5 over Terrain	1966	122,487	Fair
SW Spokane St over Duwamish River W Waterwy	1983	108,179	Fair
I-5 over Terrain	1966	106,282	Fair