Ia 1 NB over Iowa River
Johnson County, Iowa · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Ia 1 NB over Iowa River in Johnson County, Iowa, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1915 and reconstructed in 1986, making it 110 years old at the 2025 inventory.
- It carries about 10,950 vehicles a day (traffic count year 2022).
- Its listed owner is a city or municipal highway agency.
- It is one of 34 of the 376 inventoried bridges in Johnson County rated poor (9.0%); 34 (9.0%) are rated poor.
- 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 → (41.65794, -91.54165)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 5 | Fair condition |
| Superstructure | 4 | Poor condition |
| Substructure | 4 | Poor condition |
Bridge details
| Structure | Continuous concrete deck arch |
| Length | about 341 ft |
| Location | 079061000 |
| NBI structure number | 000000000031720 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Johnson County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 80 EB over Iowa River | 1960 | 32,900 | Good |
| US 218 over Deer Creek | 1970 | 32,400 | Good |
| I 80 WB over Iowa River | 1960 | 32,050 | Good |
| EB I-80 over over US 6 & Iais RR | 1995 | 31,000 | Fair |
| I 80 WB over over US 6 & Iais RR | 1992 | 31,000 | Fair |
| EB I-80 over Cic Railway | 1963 | 30,600 | Fair |
All bridges nearby: Johnson County, IA bridge conditions · every bridge in Johnson County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.