State Route 12 over Matanzas Creek
FairSonoma County, California · 04-SON-012-T17.77-SRO · Structure no. 20 0236
- Built
- 1968
- 57 years old
- Condition
- Fair
- inspected September 2024
- Type
- Tee Beam
- Concrete
- Length
- 39 ft
- 1 main span
- Daily traffic
- 40,750
- 2009 count
- Owner
- State
- State Highway Agency
About this bridge
State Route 12 over Matanzas Creek is a concrete tee beam carrying State Route 12 over Matanzas Creek in Sonoma County, California. It was built in 1968, so it is 57 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 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 40,750 vehicles a day, roughly 2% of them trucks, projected to reach 59,162 by 2046. The structure is 39 ft (11.9 m) long and 76 ft wide. If it were closed, the detour would be 3.1 mi (5 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 | 8 Very Good | No problems noted. |
| 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 State Route 12 over Matanzas Creek built?
It was built in 1968, making it 57 years old in 2025.
What condition is State Route 12 over Matanzas 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 2024.
How much traffic does State Route 12 over Matanzas Creek carry?
About 40,750 vehicles per day (2009 count), of which roughly 2% are trucks.
How long is State Route 12 over Matanzas Creek?
The structure is 39 ft (11.9 m) long with a longest span of 36 ft (11 m) and a deck 76 ft wide.
Who owns State Route 12 over Matanzas Creek?
It is owned by the State Highway Agency.