SD027 over Mud Ck
Day County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SD027 over Mud Ck in Day County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1970, making it 55 years old at the 2025 inventory.
- It carries about 209 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 10 of the 34 inventoried bridges in Day County rated fair (29.4%); 9 (26.5%) 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 → (45.45875, -97.83773)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 5 | Fair condition |
| Superstructure | 5 | Fair condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 92 ft |
| Location | 8.9 S Marshall Co Line |
| NBI structure number | 000000019070089 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Day County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| 446A Avenue over Blue Dog Lake | 2023 | 852 | Good |
| SD027 over Antelope Ck | 1970 | 428 | Fair |
| SD027 over Ck | 1970 | 428 | Fair |
| 130TH Street over Creek | 1935 | 385 | Fair |
| 130TH Street over Creek | 1930 | 376 | Good |
| 128TH Street over Creek | 2011 | 307 | Good |
All bridges nearby: Day County, SD bridge conditions · every bridge in Day County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.