S 500 over Flatwillow Creek
GoodPetroleum County, Montana · 6M SW Mosby · Structure no. S00500030+00001
- Built
- 1962
- 63 years old, rebuilt 2015
- Condition
- Good
- inspected March 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 336 ft
- 2 main spans
- Daily traffic
- 14
- 2023 count
- Owner
- County
- County Highway Agency
About this bridge
S 500 over Flatwillow Creek is a prestressed concrete stringer/multi-beam or girder carrying S 500 over Flatwillow Creek in Petroleum County, Montana. It was built in 1962 and reconstructed in 2015, so it is 63 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 14 vehicles a day, projected to reach 15 by 2043. The structure is 336 ft (102.3 m) long and 27 ft wide. If it were closed, the detour would be 55.9 mi (90 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was S 500 over Flatwillow Creek built?
It was built in 1962, making it 63 years old in 2025. It was reconstructed in 2015.
What condition is S 500 over Flatwillow Creek in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in March 2023.
How much traffic does S 500 over Flatwillow Creek carry?
About 14 vehicles per day (2023 count).
How long is S 500 over Flatwillow Creek?
The structure is 336 ft (102.3 m) long with a longest span of 102 ft (31.1 m) and a deck 27 ft wide.
Who owns S 500 over Flatwillow Creek?
It is owned by the County Highway Agency.