US 20 over Drainage
Black Hawk County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 20 over Drainage in Black Hawk 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 1980, making it 45 years old at the 2025 inventory.
- It carries about 10,700 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 210 of the 489 inventoried bridges in Black Hawk County rated fair (42.9%); 25 (5.1%) 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 → (42.45004, -92.14454)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 27 ft |
| Location | 2.4 Mi. E of E Jct. I-380 |
| NBI structure number | 000000000604960 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Black Hawk County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 218 over Quarry Lake & Wyth Rd | 1989 | 29,000 | Fair |
| US 218 over Broadway St | 1989 | 23,100 | Fair |
| US 218 over Airport Blvd | 1989 | 23,100 | Fair |
| US 218 over Cedar Rvr & Trail | 1989 | 21,500 | Fair |
| Ia 27 over Br Dry Run Creek | 1993 | 20,900 | Good |
| I 380 NB over Ianr RR Tx St Cedar Rvr | 1983 | 19,950 | Fair |
All bridges nearby: Black Hawk County, IA bridge conditions · every bridge in Black Hawk County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.