State Route 99 SB over Lone Tree Slough
FairSan Joaquin County, California · 10-SJ-099-11.80 · Structure no. 29 0023
- Built
- 1955
- 70 years old, rebuilt 2014
- Condition
- Fair
- inspected October 2024
- Type
- Slab
- Concrete Continuous
- Length
- 63 ft
- 3 main spans
- Daily traffic
- 85,000
- 2020 count
- Owner
- State
- State Highway Agency
About this bridge
State Route 99 SB over Lone Tree Slough is a concrete continuous slab carrying State Route 99 SB over Lone Tree Slough in San Joaquin County, California. It was built in 1955 and reconstructed in 2014, so it is 70 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 85,000 vehicles a day, roughly 13% of them trucks, projected to reach 92,715 by 2042. The structure is 63 ft (19.2 m) long and 135 ft wide. If it were closed, the detour would be 8.1 mi (13 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was State Route 99 SB over Lone Tree Slough built?
It was built in 1955, making it 70 years old in 2025. It was reconstructed in 2014.
What condition is State Route 99 SB over Lone Tree 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 October 2024.
How much traffic does State Route 99 SB over Lone Tree Slough carry?
About 85,000 vehicles per day (2020 count), of which roughly 13% are trucks.
How long is State Route 99 SB over Lone Tree Slough?
The structure is 63 ft (19.2 m) long with a longest span of 20 ft (6.1 m) and a deck 135 ft wide.
Who owns State Route 99 SB over Lone Tree Slough?
It is owned by the State Highway Agency.