FHWA NBI 2024 Inspection record Public-domain dataset

520TH ST

Carrying 520TH ST over BR RACCOON RIVER

092352701, Buena Vista, Iowa

Data updated May 2026

FHWA NBI record, refreshed with each annual release.

Poor
14 t Inventory load rating

Bridge Snapshot: 520TH ST

The 520TH ST bridge in Buena Vista, Iowa carries 520TH ST over BR RACCOON RIVER. It was built in 1931, making it 95 years old today. The structure is built primarily of steel and spans 1 section, stretching 7.3 meters (24 feet) end to end. Daily traffic averages 20 vehicles, placing it in the lower-traffic tier of Iowa bridges. It is owned and maintained by County Highway Agency.

The latest FHWA inspection records show a deck rating of 5/9, superstructure at 4/9, substructure at 5/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed. Its NBI inventory load rating is 13.7 metric tons.

Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.

How 520TH ST compares

▼ 17.2
Load rating vs Iowa average (30.9 t)
Bottom 7%
Lower load rating than 93% of Iowa bridges
140
Bridges in Buena Vista · 47 in Poor condition
520TH ST 13.7 t
Iowa average 30.9 t

Live comparison across Iowa.

Historical Sufficiency Rating

PlainBridge-computed
37.7 / 100 - historical 20–49.9 band
Structural adequacy /55
3.7
Serviceability /30
19.0
Essentiality /15
15.0
Special reductions
0

FHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.

Condition Ratings

Deck
5/9
Fair (5–6)
Superstructure
4/9
Poor (1–4)
Substructure
5/9
Fair (5–6)
Inventory Load Rating
13.7 t
NBI inventory level (metric tons)
Overall Condition
Poor

Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.

Structural Details

Year Built
1931
Material
Steel
Number of Spans
1
Structure Length
7.3 m (24 ft)
Deck Width
10.4 m (34 ft)
Owner
County Highway Agency
Avg Daily Traffic
20 vehicles/day
Structure Number
000000000085500

Condition Analysis

  • The deck (driving surface) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
  • The superstructure (beams and supports above the deck) rates poor at 4/9, advanced deterioration that should be prioritized for repair.
  • At 5/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.

How to read this record

520TH ST is in the federal Poor condition category. That is a component-based result, not a closure order.

  • NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
  • Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
  • Compare 520TH ST against other structures in Buena Vista and across Iowa. Iowa 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 520TH ST?

520TH ST in Buena Vista, Iowa has a deck rating of 5/9, superstructure rating of 4/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.

How often is 520TH ST inspected?

520TH ST'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 20 vehicles per day.

What does “structurally deficient” mean in older bridge reports?

FHWA retired that reported status beginning with the 2018 archive. 520TH ST is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.

What is the inventory load rating for 520TH ST?

520TH ST has an NBI inventory load rating of 13.7 metric tons.

Who is responsible for maintaining 520TH ST?

520TH ST is owned and maintained by County Highway Agency.

How old is 520TH ST and does age affect safety?

520TH ST was built in 1931, making it 95 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.

Data sourced from the Federal Highway Administration National Bridge Inventory. See our methodology for details. Retrieved and formatted by PlainBridges

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.