Birdtail Rd over Flat Creek 036
Lewis and Clark County, Montana · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Birdtail Rd over Flat Creek 036 in Lewis and Clark County, Montana, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1901, making it 124 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 11 of the 204 inventoried bridges in Lewis and Clark County rated poor (5.4%); 11 (5.4%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- It was rated fair in the 2024 inventory and is now poor (deck 6 to 5, substructure 5 to 4).
- Its most recent inspection on record is dated July 2024, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (47.25192, -112.06488)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 5 | Fair condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 5 | 4 | Poor condition |
Bridge details
| Structure | Steel through truss |
| Length | about 61 ft |
| Location | 8M SE Bowmans |
| NBI structure number | L25320003+09001 |
| Condition class | Poor |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Lewis and Clark County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Lyndale Ave-us 12 over Great Northern Area | 2003 | 20,397 | Good |
| US 12 over RR | 1978 | 19,327 | Good |
| N Last Chance Gulc over RR | 2003 | 18,569 | Good |
| E Custer Ave over Int Custer Ave-i 15 | 2012 | 16,988 | Good |
| US 12 over Prickly Pear Creek | 1978 | 15,333 | Good |
| I 15 over Sep Boulder Ave-rr | 2016 | 14,810 | Fair |
All bridges nearby: Lewis and Clark County, MT bridge conditions · every bridge in Lewis and Clark County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.