Irr County Road 20 over Smoke Creek 016
Roosevelt County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr County Road 20 over Smoke Creek 016 in Roosevelt County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1955, making it 70 years old at the 2025 inventory.
- It carries about 100 vehicles a day (traffic count year 2025).
- Its listed owner is the county highway agency.
- It is one of 36 of the 57 inventoried bridges in Roosevelt County rated fair (63.2%); 7 (12.3%) 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 2023, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- 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 → (48.47628, -104.95167)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Steel through truss |
| Length | about 94 ft |
| Location | 21M N Brockton |
| NBI structure number | L43205005+09001 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Roosevelt County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr - US 2 over Mosquito Creek | 1986 | 4,269 | Fair |
| Irr - US 2 over Little Wolf Creek | 1988 | 4,269 | Fair |
| Irr - US 2 over Poplar River | 2000 | 2,296 | Fair |
| S 16 over Sheep Creek | 1970 | 2,129 | Fair |
| Irr - US 2 over Tule Creek | 1958 | 2,054 | Fair |
| Irr - US 2 over Chelsea Creek | 1960 | 2,054 | Poor |
All bridges nearby: Roosevelt County, MT bridge conditions · every bridge in Roosevelt County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.