US Highway 101 over Colgan Creek
FairSonoma County, California · 04-SON-101-18.88 · Structure no. 20 0196
- Built
- 1957
- 68 years old
- Condition
- Fair
- inspected August 2024
- Type
- Culvert
- Concrete Continuous
- Length
- 22 ft
- 2 main spans
- Daily traffic
- 92,000
- 2016 count
- Owner
- State
- State Highway Agency
About this bridge
US Highway 101 over Colgan Creek is a concrete continuous culvert carrying US Highway 101 over Colgan Creek in Sonoma County, California. It was built in 1957, so it is 68 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 92,000 vehicles a day, roughly 6% of them trucks, projected to reach 169,580 by 2046. The structure is 22 ft (6.7 m) long. If it were closed, the detour would be 1.2 mi (2 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 |
|---|---|---|
| Channel and channel protection | 8 Very Good | No problems noted. |
| Culvert | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US Highway 101 over Colgan Creek built?
It was built in 1957, making it 68 years old in 2025.
What condition is US Highway 101 over Colgan 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 August 2024.
How much traffic does US Highway 101 over Colgan Creek carry?
About 92,000 vehicles per day (2016 count), of which roughly 6% are trucks.
How long is US Highway 101 over Colgan Creek?
The structure is 22 ft (6.7 m) long with a longest span of 10 ft (3 m).
Who owns US Highway 101 over Colgan Creek?
It is owned by the State Highway Agency.