US 310 over Rock Creek
Carbon County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 310 over Rock Creek in Carbon 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 1934 and reconstructed in 1968, making it 91 years old at the 2025 inventory.
- It carries about 4,561 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 46 of the 81 inventoried bridges in Carbon County rated fair (56.8%); 4 (4.9%) are rated poor.
- 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 → (45.51785, -108.86258)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete tee beam |
| Length | about 137 ft |
| Location | Rockvale |
| NBI structure number | P00004042+04541 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Carbon County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 310 over Sand Creek | 1987 | 4,907 | Good |
| US 212 over Rock Creek | 1974 | 3,817 | Fair |
| US 212 over Rock Creek | 2001 | 2,491 | Good |
| US 310 over Bridger Creek | 1971 | 1,932 | Fair |
| US 310 over Clarks Fk Yellowstone | 1971 | 1,932 | Fair |
| S 72 over Bear Creek | 2013 | 1,732 | Good |
All bridges nearby: Carbon County, MT bridge conditions · every bridge in Carbon County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.