402ND Avenue over North Br Twelve Mile Ck
Davison County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 402ND Avenue over North Br Twelve Mile Ck in Davison County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, 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 64 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 60 of the 123 inventoried bridges in Davison County rated fair (48.8%); 22 (17.9%) 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 July 2024, on a 24-month routine inspection cycle.
- 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 → (43.55097, -98.16488)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Concrete channel beam |
| Length | about 33 ft |
| Location | 9 W & 0.6 N Ethan |
| NBI structure number | 000000018080204 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | U: unknown foundation, not evaluated for scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Davison County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Sanborn St (SD37) over BNSF RR | 2001 | 13,545 | Fair |
| Sanborn St (SD37) over Dry Run Ck | 2001 | 13,545 | Good |
| South Burr Street over Dry Run Ck | 1990 | 11,950 | Good |
| SD037 over I090 | 1966 | 10,351 | Fair |
| SD037 over Dry Run Ck | 1996 | 9,756 | Good |
| SD037 over 4TH Ave BNSF RR | 1997 | 7,642 | Good |
All bridges nearby: Davison County, SD bridge conditions · every bridge in Davison County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.