N4520
Carrying N4520 over CREEK
3.0NE 1.8 E OF AFRON, Ottawa, Oklahoma
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: N4520
The N4520 bridge in Ottawa, Oklahoma carries N4520 over CREEK. It was built in 1939, making it 87 years old today. The structure is built primarily of concrete continuous and spans 2 sections, stretching 9.2 meters (30 feet) end to end. Daily traffic averages 100 vehicles, placing it in the lower-traffic tier of Oklahoma bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show culvert at 5/9. 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 10.8 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How N4520 compares
Live comparison across Oklahoma.
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 How the historical reference is calculated.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
- 1939
- Material
- Concrete Continuous
- Number of Spans
- 2
- Structure Length
- 9.2 m (30 ft)
- Deck Width
- 6.2 m (20 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 100 vehicles/day
- Structure Number
- 066120000000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether N4520 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 N4520 against other structures in Ottawa and across Oklahoma. Oklahoma 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 N4520?
N4520 in Ottawa, Oklahoma on the FHWA's 0–9 scale.
How often is N4520 inspected?
N4520'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 100 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. N4520 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 N4520?
N4520 has an NBI inventory load rating of 10.8 metric tons.
Who is responsible for maintaining N4520?
N4520 is owned and maintained by County Highway Agency.
How old is N4520 and does age affect safety?
N4520 was built in 1939, making it 87 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.