Frontage Road 146 over Drainage 032
Deer Lodge County, Montana · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Frontage Road 146 over Drainage 032 in Deer Lodge County, Montana, 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 1931 and reconstructed in 1940, making it 94 years old at the 2025 inventory.
- It carries about 100 vehicles a day (traffic count year 2025).
- Its listed owner is the state highway agency.
- It is one of 26 of the 67 inventoried bridges in Deer Lodge County rated good (38.8%); 3 (4.5%) 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 December 2023, on a 24-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 → (46.14269, -112.7954)
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 | Concrete tee beam |
| Length | about 30 ft |
| Location | 3M S Warm Springs |
| NBI structure number | L12146001+09001 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | December 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Deer Lodge County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Lost Creek | 1978 | 11,628 | Fair |
| I 90 over Willow Creek | 1978 | 10,417 | Fair |
| I 90 over Int Galen | 1978 | 5,814 | Fair |
| I 90 over Int Galen | 1978 | 5,814 | Good |
| I 90 over Sep Perkins Lane | 1978 | 5,814 | Fair |
| I 90 over Sep Huffman Lane | 1978 | 5,814 | Fair |
All bridges nearby: Deer Lodge County, MT bridge conditions · every bridge in Deer Lodge County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.