US 310 over Sand Creek
Carbon County, Montana · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 310 over Sand Creek in Carbon County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 1987, making it 38 years old at the 2025 inventory.
- It carries about 4,907 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 31 of the 81 inventoried bridges in Carbon County rated good (38.3%); 4 (4.9%) 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 October 2024, 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 → (45.33834, -108.91676)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 7 | 7 | Good condition |
Bridge details
| Structure | Steel culvert |
| Length | about 25 ft |
| Location | 4M S Fromberg |
| NBI structure number | P00004029+01101 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2024 |
| 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 Carbon County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 310 over Rock Creek | 1934 | 4,561 | Fair |
| 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.