State Route 99 SB over Willow Slough
FairSacramento County, California · 03-SAC-099-6.54 · Structure no. 24 0046L
- Built
- 1927
- 98 years old, rebuilt 1958
- Condition
- Fair
- inspected July 2024
- Type
- Tee Beam
- Concrete
- Length
- 61 ft
- 3 main spans
- Daily traffic
- 31,500
- 2019 count
- Owner
- State
- State Highway Agency
About this bridge
State Route 99 SB over Willow Slough is a concrete tee beam carrying State Route 99 SB over Willow Slough in Sacramento County, California. It was built in 1927 and reconstructed in 1958, so it is 98 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 31,500 vehicles a day, roughly 18% of them trucks, projected to reach 55,865 by 2046. The structure is 61 ft (18.5 m) long and 38 ft wide. If it were closed, the detour would be 8.7 mi (14 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 | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was State Route 99 SB over Willow Slough built?
It was built in 1927, making it 98 years old in 2025. It was reconstructed in 1958.
What condition is State Route 99 SB over Willow Slough 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 July 2024.
How much traffic does State Route 99 SB over Willow Slough carry?
About 31,500 vehicles per day (2019 count), of which roughly 18% are trucks.
How long is State Route 99 SB over Willow Slough?
The structure is 61 ft (18.5 m) long with a longest span of 20 ft (6.1 m) and a deck 38 ft wide.
Who owns State Route 99 SB over Willow Slough?
It is owned by the State Highway Agency.