Petroleum Rd over Big Porcupine CR
Rosebud County, Montana · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Petroleum Rd over Big Porcupine CR in Rosebud County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 7 (good condition) on the 0-9 scale.
- It was built in 2022, making it 3 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 18 of the 112 inventoried bridges in Rosebud County rated good (16.1%); 7 (6.2%) 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 September 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 → (46.5847, -107.0957)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 8 | 8 | Very good condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 53 ft |
| Location | 14M E Ingomar |
| NBI structure number | 000000202204275 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 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 Rosebud County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr Bia Rte 6 over Lame Deer Creek | 1976 | 3,000 | Good |
| I 94 over Int East Forsyth | 1977 | 2,749 | Fair |
| I 94 over Int East Forsyth | 1977 | 2,749 | Fair |
| I 94 over Int W Rosebud 446-447 | 1970 | 2,636 | Fair |
| I 94 over Int W Rosebud 446-447 | 1970 | 2,636 | Fair |
| I 94 over Rosebud Creek | 1970 | 2,636 | Fair |
All bridges nearby: Rosebud County, MT bridge conditions · every bridge in Rosebud County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.