US 18 over Unnamed Creek
Clayton County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 18 over Unnamed Creek in Clayton County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1988, making it 37 years old at the 2025 inventory.
- It carries about 4,730 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 141 of the 257 inventoried bridges in Clayton County rated fair (54.9%); 38 (14.8%) are rated poor.
- 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 → (43.04394, -91.18547)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 43 ft |
| Location | 0.1 mi. E of jct. SR B45 |
| NBI structure number | 000000000605900 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Clayton County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 18 over Mississippi River Ia 76 | 1974 | 10,100 | Fair |
| Ia 13 over Roberts Creek | 1979 | 4,900 | Good |
| Bridge St over Turkey River | 1889 | 4,755 | Fair |
| US 18 & 52 over Branch Roberts Creek | 1967 | 4,140 | Fair |
| US 18 over Bloody Run & Dme RR | 1988 | 4,140 | Fair |
| US 18 & 52 over Natural Stream | 1967 | 3,780 | Good |
All bridges nearby: Clayton County, IA bridge conditions · every bridge in Clayton County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.