Mariposa St over Caltrain & UP RR
San Francisco County, California · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Mariposa St over Caltrain & UP RR in San Francisco County, California, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- It was built in 1968, making it 57 years old at the 2025 inventory.
- It carries about 20,000 vehicles a day (traffic count year 2017).
- Its listed owner is the county highway agency.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (37.76401, -122.39328)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 4 | Poor condition |
| Superstructure | 8 | Very good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Continuous concrete multiple box beam |
| Length | about 100 ft |
| Location | at SR 280 |
| NBI structure number | 34C0005 |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
All bridges nearby: San Francisco County, CA bridge conditions · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.