Irr I029 N over Drainage Ditch
Roberts County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr I029 N over Drainage Ditch in Roberts County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1980, making it 45 years old at the 2025 inventory.
- It carries about 2,570 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 77 of the 158 inventoried bridges in Roberts County rated fair (48.7%); 40 (25.3%) 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 → (45.73278, -96.93986)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 6 | Satisfactory condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 80 ft |
| Location | 5.5 NE Sd 10 Interch |
| NBI structure number | 000000055140140 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Roberts County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr SD010 over Ck | 2019 | 7,072 | Good |
| Irr SD010 over Ck | 1979 | 6,275 | Fair |
| 458TH Avenue over Creek | 1941 | 5,850 | Fair |
| 458TH Avenue over Creek | 1941 | 5,850 | Fair |
| 459TH Avenue over Creek | 1941 | 5,850 | Good |
| Irr I029 over Big Spring Ck | 1978 | 5,340 | Fair |
All bridges nearby: Roberts County, SD bridge conditions · every bridge in Roberts County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.