Structure I00090180+04301 · Powell County, MT
Carries I 90 over Jr Grade Sep, 6.2m N Deer Lodge.
Set by its lowest-rated component: Deck and Superstructure and Substructure at 6 of 9.
How ratings work23 ft end to end. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a slab bridge.
| State | Montana |
| County | Powell |
| Location | 6.2m N Deer Lodge |
| Carries | I 90 |
| Crosses | Jr Grade Sep |
| Coordinates | 46.47663, -112.72318 |
| Material | Concrete |
| Design | Slab |
| Total Length | 22.6 ft (6.9 m) |
| Max Span | 21.3 ft (6.5 m) |
| Deck Width | 124.0 ft (37.8 m) |
| Deck Area | 260.8 sq m |
| Main Spans | 1 |
| Year Built | 1961 (reconstructed 1978) |
| Avg Daily Traffic | 10,463 (2023) |
| Truck Traffic | 20% |
| Lanes On Bridge | 4 |
| Lanes Under Bridge | 2 |
| Last Inspection | May 2024 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | Not applicable |
| Structure Number | I00090180+04301 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.