US Highway 101 SB over Zanzi LN
FairSonoma County, California · 04-SON-101-R46.00 · Structure no. 20 0222L
- Built
- 1964
- 61 years old
- Condition
- Fair
- inspected April 2023
- Type
- Tee Beam
- Concrete Continuous
- Length
- 128 ft
- 3 main spans
- Daily traffic
- 10,850
- 2015 count
- Owner
- State
- State Highway Agency
About this bridge
US Highway 101 SB over Zanzi LN is a concrete continuous tee beam carrying US Highway 101 SB over Zanzi LN in Sonoma County, California. It was built in 1964, so it is 61 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 10,850 vehicles a day, roughly 9% of them trucks, projected to reach 19,828 by 2045. The structure is 128 ft (39 m) long and 40 ft wide. If it were closed, the detour would be 19.9 mi (32 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 | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US Highway 101 SB over Zanzi LN built?
It was built in 1964, making it 61 years old in 2025.
What condition is US Highway 101 SB over Zanzi LN 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 April 2023.
How much traffic does US Highway 101 SB over Zanzi LN carry?
About 10,850 vehicles per day (2015 count), of which roughly 9% are trucks.
How long is US Highway 101 SB over Zanzi LN?
The structure is 128 ft (39 m) long with a longest span of 54 ft (16.5 m) and a deck 40 ft wide.
Who owns US Highway 101 SB over Zanzi LN?
It is owned by the State Highway Agency.