Interstate 5 over Dunsmuir Ave
Siskiyou County, California · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Interstate 5 over Dunsmuir Ave in Siskiyou County, California, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1976, making it 49 years old at the 2025 inventory.
- It carries about 19,200 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 170 of the 425 inventoried bridges in Siskiyou County rated good (40.0%); 25 (5.9%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (41.23533, -122.26959)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 104 ft |
| Location | 02-sis-005-3.84-dmr |
| NBI structure number | 02 0171 |
| Condition class | Good |
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 Sacramento UP RR Amtrak | 1955 | 18,000 | Good |
| Interstate 5 over Little Castle Creek | 1960 | 18,000 | Fair |
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.