Franz Valley Road over Franz Creek
Sonoma County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Franz Valley Road over Franz Creek in Sonoma County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1977, making it 48 years old at the 2025 inventory.
- It carries about 500 vehicles a day (traffic count year 2015).
- Its listed owner is the county highway agency.
- It is one of 441 of the 611 inventoried bridges in Sonoma County rated fair (72.2%); 32 (5.2%) 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: superstructure 5 to 7.
- Its most recent inspection on record is dated July 2023, on a 24-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 → (38.60837, -122.69471)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 7 | Good condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 80 ft |
| Location | 2 Miles SW of SR 128 |
| NBI structure number | 20C0327 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2023 |
| Inspection interval (item 91) | 24 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 Sonoma County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US Highway 101 over College Avenue | 2009 | 136,500 | Fair |
| U.S. Route 101 over Future Rainier Avenue | 2022 | 103,000 | Fair |
| US Highway 101 over 3RD St 4TH St & 5TH St | 1968 | 96,000 | Fair |
| US Highway 101 over Ninth Street | 1968 | 96,000 | Fair |
| U.S. Highway 101 over Santa Rosa Creek | 2009 | 96,000 | Fair |
| U.S. Highway 101 over Sixth Street | 2009 | 96,000 | Fair |
All bridges nearby: Sonoma County, CA bridge conditions · every bridge in Sonoma County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.