Calistoga RD over Humbug Creek
FairSonoma County, California · 4.9 MI N/O SR 12 · Structure no. 20C0121
- Built
- 1935
- 90 years old, rebuilt 1962
- Condition
- Fair
- inspected October 2024
- Type
- Slab
- Concrete
- Length
- 25 ft
- 1 main span
- Daily traffic
- 5,800
- 2015 count
- Owner
- County
- County Highway Agency
About this bridge
Calistoga RD over Humbug Creek is a concrete slab carrying Calistoga RD over Humbug Creek in Sonoma County, California. It was built in 1935 and reconstructed in 1962, so it is 90 years old, older than the California average of 54.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 5,800 vehicles a day, roughly 5% of them trucks, projected to reach 4,940 by 2046. The structure is 25 ft (7.6 m) long and 28 ft wide. If it were closed, the detour would be 11.8 mi (19 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Calistoga RD over Humbug Creek built?
It was built in 1935, making it 90 years old in 2025. It was reconstructed in 1962.
What condition is Calistoga RD over Humbug 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 October 2024.
How much traffic does Calistoga RD over Humbug Creek carry?
About 5,800 vehicles per day (2015 count), of which roughly 5% are trucks.
How long is Calistoga RD over Humbug Creek?
The structure is 25 ft (7.6 m) long with a longest span of 24 ft (7.3 m) and a deck 28 ft wide.
Who owns Calistoga RD over Humbug Creek?
It is owned by the County Highway Agency.