I-405
Carrying I-405 over NORTHUP WAY
0.1 N JCT SR 520, King, Washington
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: I-405
The I-405 bridge in King, Washington carries I-405 over NORTHUP WAY. It was built in 1965, making it 61 years old today. It was last reconstructed in 1993, extending its service life. The structure is built primarily of prestressed concrete continuous and spans 3 sections, stretching 48.8 meters (160 feet) end to end. Daily traffic averages 65,986 vehicles, placing it in the heavily-trafficked tier of Washington bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in good condition. None of this bridge's reported major components fall into the Poor condition range. Its NBI inventory load rating is 41.7 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How I-405 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 How the historical reference is calculated.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
- 1965
- Last Reconstructed
- 1993
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 3
- Structure Length
- 48.8 m (160 ft)
- Deck Width
- 23.8 m (78 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 65,986 vehicles/day
- Structure Number
- 0007596E0000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • At 7/9, the superstructure (beams and supports above the deck) is in good shape and shows no significant wear.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
How to read this record
This page shows what the last federal inspection recorded, not whether I-405 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 I-405 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 I-405?
I-405 in King, Washington has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is I-405 inspected?
I-405'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 65,986 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. I-405 is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for I-405?
I-405 has an NBI inventory load rating of 41.7 metric tons.
Who is responsible for maintaining I-405?
I-405 is owned and maintained by State Highway Agency.
How old is I-405 and does age affect safety?
I-405 was built in 1965, making it 61 years old and last reconstructed in 1993.
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.