56TH AVE SO
Carrying 56TH AVE SO over DUWAMISH RIVER
0.1E INTERURBAN AVE, King, Washington
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: 56TH AVE SO
The 56TH AVE SO bridge in King, Washington carries 56TH AVE SO over DUWAMISH RIVER. It was built in 1985, making it 41 years old today. The structure is built primarily of concrete continuous and spans 2 sections, stretching 74.4 meters (244 feet) end to end. Daily traffic averages 2,900 vehicles, placing it in the moderately-trafficked tier of Washington bridges. It is owned and maintained by City/Municipal Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 6/9. The weakest component sits in fair condition. None of this bridge's reported major components fall into the Poor condition range. Its NBI inventory load rating is 28.8 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How 56TH AVE SO compares
Live comparison across Washington.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1985
- Material
- Concrete Continuous
- Number of Spans
- 2
- Structure Length
- 74.4 m (244 ft)
- Deck Width
- 10.6 m (35 ft)
- Owner
- City/Municipal Highway Agency
- Avg Daily Traffic
- 2,900 vehicles/day
- Structure Number
- 081662000000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 7/9, the deck (driving surface) is in good shape and shows no significant wear.
- • At 7/9, the superstructure (beams and supports above the deck) is in good shape and shows no significant wear.
- • The substructure (piers and abutments) rates fair at 6/9, minor deterioration that routine maintenance should address.
How to read this record
This page shows what the last federal inspection recorded, not whether 56TH AVE SO is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare 56TH AVE SO against other structures in King and across Washington. Washington bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for 56TH AVE SO?
56TH AVE SO in King, Washington has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is 56TH AVE SO inspected?
56TH AVE SO's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 2,900 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 56TH AVE SO is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 56TH AVE SO?
56TH AVE SO has an NBI inventory load rating of 28.8 metric tons.
Who is responsible for maintaining 56TH AVE SO?
56TH AVE SO is owned and maintained by City/Municipal Highway Agency.
How old is 56TH AVE SO and does age affect safety?
56TH AVE SO was built in 1985, making it 41 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.