Forest Road 492 over Twenty Mile Creek
FairIdaho County, Idaho · No Data Entered · Structure no. 011708000000106
- Built
- 1958
- 67 years old
- Condition
- Fair
- inspected September 2020
- Type
- Stringer/Multi-beam or Girder
- Wood or Timber
- Length
- 28 ft
- 1 main span
- Daily traffic
- 40
- Owner
- Federal
- U.S. Forest Service
About this bridge
Forest Road 492 over Twenty Mile Creek is a wood or timber stringer/multi-beam or girder carrying Forest Road 492 over Twenty Mile Creek in Idaho County, Idaho. It was built in 1958, so it is 67 years old, older than the Idaho average of 45.3 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 40 vehicles a day, projected to reach 60 by 2045. The structure is 28 ft (8.5 m) long and 15 ft wide. If it were closed, the detour would be 98.2 mi (158 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Forest Road 492 over Twenty Mile Creek built?
It was built in 1958, making it 67 years old in 2025.
What condition is Forest Road 492 over Twenty Mile Creek in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in September 2020.
How much traffic does Forest Road 492 over Twenty Mile Creek carry?
About 40 vehicles per day (latest count).
How long is Forest Road 492 over Twenty Mile Creek?
The structure is 28 ft (8.5 m) long with a longest span of 27 ft (8.2 m) and a deck 15 ft wide.
Who owns Forest Road 492 over Twenty Mile Creek?
It is owned by the U.S. Forest Service.