Purdon Road over South Yuba River
Nevada County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Purdon Road over South Yuba River in Nevada County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1895 and reconstructed in 1951, making it 130 years old at the 2025 inventory.
- It carries about 71 vehicles a day (traffic count year 2018).
- Its listed owner is the county highway agency.
- It is one of 55 of the 137 inventoried bridges in Nevada County rated fair (40.1%); 19 (13.9%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- It was rated poor in the 2024 inventory and is now fair (deck 7 to 8, superstructure 5 to 7, substructure 4 to 5).
- Its most recent inspection on record is dated August 2024, on a 12-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- 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 → (39.32749, -121.04658)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 8 | Very good condition |
| Superstructure | 5 | 7 | Good condition |
| Substructure | 4 | 5 | Fair condition |
Bridge details
| Structure | Steel through truss |
| Length | about 191 ft |
| Location | 2.0 Mi S Tyler-foote |
| NBI structure number | 17C0024 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | August 2024 |
| Inspection interval (item 91) | 12 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Nevada County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 20 over Idaho-maryland Road | 1969 | 47,000 | Fair |
| State Route 20 over Wolf Creek | 1969 | 47,000 | Good |
| State Route 20 over SR 174 (colfax) Auburn | 1970 | 43,000 | Good |
| State Route 20 over Bank Street | 1969 | 34,500 | Good |
| State Route 20 over Bennett Street | 1969 | 34,500 | Fair |
| Interstate 80 over Donner Pass Road | 1991 | 34,000 | Fair |
All bridges nearby: Nevada County, CA bridge conditions · every bridge in Nevada County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.