I090 W over SD090 L
Lyman County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I090 W over SD090 L 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 1971, making it 54 years old at the 2025 inventory.
- It carries about 4,382 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.
- 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 January 2023, on a 48-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 → (43.80111, -99.39491)
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 | Continuous steel stringer or multi-beam girder |
| Length | about 194 ft |
| Location | Oacoma Interchange |
| NBI structure number | 000000043485272 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 2023 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | N: not over a waterway |
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 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 |
| I090 W over 321 Ave | 1971 | 3,852 | 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.