Interstate 505 over Union School Slough
Yolo County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Interstate 505 over Union School Slough in Yolo County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1980, making it 45 years old at the 2025 inventory.
- It carries about 12,000 vehicles a day (traffic count year 2010).
- Its listed owner is the state highway agency.
- It is one of 141 of the 274 inventoried bridges in Yolo County rated fair (51.5%); 12 (4.4%) are rated poor.
- 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 → (38.60839, -121.95314)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 6 | Satisfactory condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 61 ft |
| Location | 03-yol-505-5.71 |
| NBI structure number | 22 0114R |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Yolo County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Interstate 80 over Enterprise Blvd | 1951 | 145,000 | Good |
| Interstate 80 over County Road 32 | 1962 | 135,000 | Good |
| Interstate 80 over Yolo Causeway West | 1962 | 135,000 | Good |
| Interstate 80 over Yolo Causeway East | 1963 | 135,000 | Good |
| Interstate 80 over Bike & Pedestrian Tunnel | 2001 | 128,000 | Fair |
| US Hwy 50 (I-305) over Westacre Rd | 1951 | 90,000 | Poor |
All bridges nearby: Yolo County, CA bridge conditions · every bridge in Yolo County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.