478TH Avenue over Deer Ck
Brookings County, South Dakota · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 478TH Avenue over Deer Ck in Brookings County, South Dakota, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- It was built in 1950, making it 75 years old at the 2025 inventory.
- It carries about 712 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- 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 → (44.36477, -96.64658)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 3 | Serious condition |
| Superstructure | 4 | Poor condition |
| Substructure | 4 | Poor condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 29 ft |
| Location | 2.7N Bushnell |
| NBI structure number | 000000006240123 |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
All bridges nearby: Brookings County, SD bridge conditions · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.