FM 520TH St over Iowa River
Johnson County, Iowa · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- FM 520TH St over Iowa River in Johnson County, Iowa, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- It was built in 1971, making it 54 years old at the 2025 inventory.
- It carries about 2,060 vehicles a day (traffic count year 2021).
- Its listed owner is the county highway agency.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (41.55481, -91.51921)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 4 | Poor condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 348 ft |
| Location | 078062301 |
| NBI structure number | 000000000203355 |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
All bridges nearby: Johnson County, IA bridge conditions · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.