Interstate 5 SB over State Route 3
Siskiyou County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Interstate 5 SB over State Route 3 in Siskiyou 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 1970, making it 55 years old at the 2025 inventory.
- It carries about 8,300 vehicles a day (traffic count year 2015).
- Its listed owner is the state highway agency.
- It is one of 230 of the 425 inventoried bridges in Siskiyou County rated fair (54.1%); 25 (5.9%) 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 → (41.73953, -122.62814)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 5 | Fair condition |
| Superstructure | 7 | Good condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 124 ft |
| Location | 02-sis-005-r48.23-yre |
| NBI structure number | 02 0150L |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Siskiyou County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Interstate 5 SB over UP RR & Amtrak | 1964 | 20,000 | Fair |
| Interstate 5 NB over UP RR & Amtrak | 1964 | 20,000 | Fair |
| Interstate 5 over Mott Road | 1976 | 20,000 | Good |
| Interstate 5 over Mott Road | 1976 | 20,000 | Fair |
| Interstate 5 over Dunsmuir Ave | 1976 | 19,200 | Good |
| Interstate 5 over Sacramento UP RR Amtrak | 1955 | 18,000 | Good |
All bridges nearby: Siskiyou County, CA bridge conditions · every bridge in Siskiyou County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.