State Route 121 over Branch Arroyo Seco
Fair Condition104 years old19,000 vehicles/day
Location
| State | California |
| County | Sonoma |
| Location | 04-son-121-8.51 |
| Carries | State Route 121 |
| Crosses | Branch Arroyo Seco |
| Coordinates | 38.24618, -122.43270 |
Condition Ratings
| Overall Condition | Fair |
| Deck | 6 (Satisfactory) |
| Superstructure | 6 (Satisfactory) |
| Substructure | 8 (Very Good) |
| Channel/Waterway | 6 (Satisfactory) |
| Scour Critical | 8 — Stable, low risk |
Physical Characteristics
| Material | Concrete |
| Design | Slab |
| Total Length | 22.0 ft (6.7 m) |
| Max Span | 20.0 ft (6.1 m) |
| Deck Width | 26.9 ft (8.2 m) |
| Deck Area | 54.9 sq m |
| Main Spans | 1 |
| Year Built | 1922 |
Traffic
| Avg Daily Traffic | 19,000 (2014) |
| Truck Traffic | 7% |
| Lanes On Bridge | 2 |
Inspection & Ownership
| Last Inspection | 924 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Structure Number | 20 0121 |