Irr US018 over Branch of Choteau Ck
Douglas County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr US018 over Branch of Choteau Ck in Douglas County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1961, making it 64 years old at the 2025 inventory.
- It carries about 556 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 18 of the 44 inventoried bridges in Douglas County rated fair (40.9%); 7 (15.9%) 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 July 2023, on a 24-month routine inspection cycle.
- 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 → (43.23937, -98.24579)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 128 ft |
| Location | 0.1 E Charles Mix Co Line |
| NBI structure number | 000000022232180 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Douglas County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SD044 over Choteau Ck | 1961 | 1,785 | Fair |
| SD044 over Br Choteau Ck | 1960 | 1,785 | Good |
| SD044 over Andes Ck | 1957 | 1,516 | Fair |
| US281 over Ck | 1998 | 1,232 | Good |
| Irr US018 over Creek | 1961 | 556 | Poor |
| US018 over Oak Hollow Ck | 1961 | 556 | Fair |
All bridges nearby: Douglas County, SD bridge conditions · every bridge in Douglas County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.