29850 407TH Avenue over Trib to Dry Choteau Crk
Bon Homme County, South Dakota · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 29850 407TH Avenue over Trib to Dry Choteau Crk in Bon Homme County, South Dakota, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1930, making it 95 years old at the 2025 inventory.
- It carries about 60 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 34 of the 126 inventoried bridges in Bon Homme County rated poor (27.0%); 34 (27.0%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated May 2023, on a 24-month routine inspection cycle.
- 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 → (43.06146, -98.04933)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 4 | 4 | Poor condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 25 ft |
| Location | 3.5N of Avon |
| NBI structure number | 000000005060075 |
| Condition class | Poor |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | U: unknown foundation, not evaluated for scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Bon Homme County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SD050 over Drainage Ditch | 1955 | 2,674 | Good |
| SD050 over Snatch Ck | 1956 | 2,649 | Fair |
| SD050 over Charley Ck | 1979 | 2,510 | Good |
| SD050 over West Br Emanuel Ck | 1960 | 2,498 | Fair |
| SD050 over Emanuel Ck | 1960 | 2,498 | Fair |
| SD037 over Unnamed Ck | 2019 | 1,604 | Good |
All bridges nearby: Bon Homme County, SD bridge conditions · every bridge in Bon Homme County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.