32201 478TH Ave. over Lewis Ditch
Union County, South Dakota · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 32201 478TH Ave. over Lewis Ditch in Union County, South Dakota, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1940 and reconstructed in 1968, making it 85 years old at the 2025 inventory.
- It carries about 40 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 41 of the 169 inventoried bridges in Union County rated poor (24.3%); 41 (24.3%) are rated poor.
- 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 → (42.72193, -96.64554)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 4 | Poor condition |
| Superstructure | 4 | Poor condition |
| Substructure | 4 | Poor condition |
Bridge details
| Structure | Concrete channel beam |
| Length | about 62 ft |
| Location | 2E & 1.9N Elk Point |
| NBI structure number | 000000064080251 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Union County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I029 S over Big Sioux Rv | 1990 | 18,090 | Good |
| I029 N over Big Sioux Rv | 1963 | 18,090 | Fair |
| I029 over Ck | 1961 | 11,970 | Good |
| I029 over Ck | 1961 | 11,970 | Good |
| I029 over Ck | 1961 | 11,970 | Good |
| I029 S over River Drive | 1981 | 9,870 | Good |
All bridges nearby: Union County, SD bridge conditions · every bridge in Union County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.