State Route 99 SB over Willow Slough
Sacramento County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- State Route 99 SB over Willow Slough in Sacramento County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1927 and reconstructed in 1958, making it 98 years old at the 2025 inventory.
- It carries about 31,500 vehicles a day (traffic count year 2019).
- Its listed owner is the state highway agency.
- It is one of 329 of the 737 inventoried bridges in Sacramento County rated fair (44.6%); 16 (2.2%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: substructure 6 to 7.
- Its most recent inspection on record is dated July 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (38.33232, -121.33063)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 6 | 7 | Good condition |
Bridge details
| Structure | Concrete tee beam |
| Length | about 60 ft |
| Location | 03-sac-099-6.54 |
| NBI structure number | 24 0046L |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Sacramento County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| U.S. Highway 50 over 39TH Street | 1971 | 231,000 | Good |
| U.S. Highway 50 over 65TH Street | 1971 | 231,000 | Good |
| Interstate 80 over Winters Street | 1970 | 200,000 | Good |
| State Route 99 over 21ST Ave | 1959 | 193,000 | Good |
| State Route 99 over 2ND Ave | 1959 | 193,000 | Good |
| State Route 99 over Broadway | 1961 | 193,000 | Good |
All bridges nearby: Sacramento County, CA bridge conditions · every bridge in Sacramento County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.