State Route 128 over Hopper Slough
PoorNapa County, California · 04-NAP-128-5.12 · Structure no. 21 0019
- Built
- 1921
- 104 years old
- Condition
- Poor
- inspected April 2024
- Type
- Girder and Floorbeam System
- Concrete
- Length
- 41 ft
- 1 main span
- Daily traffic
- 2,075
- 2009 count
- Owner
- State
- State Highway Agency
About this bridge
State Route 128 over Hopper Slough is a concrete girder and floorbeam system carrying State Route 128 over Hopper Slough in Napa County, California. It was built in 1921, so it is 104 years old, older than the California average of 54.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 2,075 vehicles a day, roughly 5% of them trucks, projected to reach 3,331 by 2046. The structure is 41 ft (12.5 m) long and 23 ft wide. If it were closed, the detour would be 6.8 mi (11 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 3 Serious | Loss of section, deterioration, spalling or scour have seriously affected primary structural components. |
| 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 128 over Hopper Slough built?
It was built in 1921, making it 104 years old in 2025.
What condition is State Route 128 over Hopper Slough in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in April 2024.
How much traffic does State Route 128 over Hopper Slough carry?
About 2,075 vehicles per day (2009 count), of which roughly 5% are trucks.
How long is State Route 128 over Hopper Slough?
The structure is 41 ft (12.5 m) long with a longest span of 39 ft (11.9 m) and a deck 23 ft wide.
Who owns State Route 128 over Hopper Slough?
It is owned by the State Highway Agency.