Irr SD1806 over Cedar Ck
Lyman County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr SD1806 over Cedar Ck in Lyman 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 1997, making it 28 years old at the 2025 inventory.
- It carries about 161 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 46 of the 114 inventoried bridges in Lyman County rated good (40.4%); 12 (10.5%) are rated poor.
- 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 → (44.14492, -99.93285)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 7 | Good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 137 ft |
| Location | 6.4 NW Jct Sd 273 |
| NBI structure number | 000000043218036 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Lyman County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I090 W over SD090 L | 1971 | 4,382 | Good |
| I090 E over SD090 L | 1971 | 4,382 | Good |
| I090 W over SD273 | 1970 | 3,955 | Fair |
| I090 E over SD273 | 1970 | 3,955 | Fair |
| I090 W over 319 Ave | 1971 | 3,955 | Fair |
| I090 E over 319 Ave | 1971 | 3,955 | Fair |
All bridges nearby: Lyman County, SD bridge conditions · every bridge in Lyman County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.