I 90 over Sep Garrison Frontage Rd
Powell County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I 90 over Sep Garrison Frontage Rd in Powell County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1973, making it 52 years old at the 2025 inventory.
- It carries about 5,136 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 70 of the 113 inventoried bridges in Powell County rated fair (61.9%); 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 August 2024, on a 24-month routine inspection cycle.
- 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 → (46.5423, -112.84696)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 78 ft |
| Location | 2.5M W Garrison |
| NBI structure number | I00090171+07791 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | August 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Powell County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Dempsey Creek | 1973 | 10,708 | Fair |
| I 90 over Jr Grade Sep | 1961 | 10,463 | Fair |
| I 90 over Jr Grade Sep | 1961 | 10,463 | Fair |
| I 90 over Int Jens | 1959 | 5,992 | Fair |
| I 90 over Int Jens | 1959 | 5,992 | Fair |
| I 90 EB over Int Gold Creek | 1959 | 5,992 | Fair |
All bridges nearby: Powell County, MT bridge conditions · every bridge in Powell County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.