347TH St over I-80
Dallas County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 347TH St over I-80 in Dallas County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1966, making it 59 years old at the 2025 inventory.
- It carries about 103 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 92 of the 206 inventoried bridges in Dallas County rated fair (44.7%); 18 (8.7%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2023, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (41.53524, -94.03577)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 291 ft |
| Location | 1.2 mi. W of Jct. US 169 |
| NBI structure number | 000000000022270 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Dallas County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-80 over Panther Creek | 1965 | 32,100 | Good |
| I-80 over Bear Creek | 1965 | 29,500 | Good |
| EB I-80 over over UP RR | 1966 | 27,550 | Fair |
| WB I-80 over over UP RR | 1966 | 26,850 | Fair |
| EB I-80 over Sugar Creek | 1966 | 24,500 | Fair |
| WB I-80 over Sugar Creek | 1966 | 24,050 | Fair |
All bridges nearby: Dallas County, IA bridge conditions · every bridge in Dallas County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.