Irr Bia Rte 4 over Highbank Creek Bridge
Corson County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr Bia Rte 4 over Highbank Creek Bridge in Corson County, South Dakota, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 2008, making it 17 years old at the 2025 inventory.
- It carries about 109 vehicles a day (traffic count year 2023).
- It is one of 19 of the 49 inventoried bridges in Corson County rated good (38.8%); 4 (8.2%) 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 good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (45.62899, -100.90451)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 95 ft |
| Location | 8.93KM SW of Little Eagle |
| NBI structure number | 00000000000A149 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Corson County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr US012 over Claymore Ck | 1958 | 1,378 | Poor |
| Irr US012 over Deep Bank Ck | 1965 | 1,091 | Fair |
| Irr US012 over Br Snake Ck | 1965 | 1,091 | Fair |
| Irr US012 over Snake Ck | 1966 | 1,091 | Fair |
| Irr SD020 over Ck | 2000 | 956 | Good |
| Irr SD063 over Oak Ck | 1980 | 864 | Fair |
All bridges nearby: Corson County, SD bridge conditions · every bridge in Corson County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.