US 18 over Drainage Ditch
Sioux County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 18 over Drainage Ditch in Sioux 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 1976, making it 49 years old at the 2025 inventory.
- It carries about 5,200 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 153 of the 448 inventoried bridges in Sioux County rated fair (34.2%); 14 (3.1%) 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 → (43.18599, -96.09147)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 32 ft |
| Location | 2.3 mi. E of Jct. SR K52 |
| NBI structure number | 000000000048311 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Sioux County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 75 over W Fork Floyd River | 1989 | 7,300 | Good |
| US 75 over Stream | 1998 | 7,300 | Good |
| US 18 over Rogg Creek | 1985 | 6,700 | Good |
| Ia 60 over Stream | 1991 | 6,500 | Good |
| Ia 10 over Floyd River | 1993 | 5,300 | Fair |
| US 18 over West Fork Floyd River | 1976 | 5,200 | Fair |
All bridges nearby: Sioux County, IA bridge conditions · every bridge in Sioux County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.