Armstrong Road over Willow Creek
Lassen County, California · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Armstrong Road over Willow Creek in Lassen 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 1995, making it 30 years old at the 2025 inventory.
- It carries about 50 vehicles a day (traffic count year 1998).
- Its listed owner is the county highway agency.
- It is one of 28 of the 108 inventoried bridges in Lassen County rated good (25.9%); 8 (7.4%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated October 2023, on a 48-month routine inspection cycle.
- 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 → (41.10793, -120.92866)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 52 ft |
| Location | 0.25 Mi. S. of Susanv. Rd |
| NBI structure number | 07C0086 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2023 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Lassen County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 36 over Susan River | 1964 | 15,300 | Fair |
| State Route 36 over Jensen Slough | 1964 | 15,300 | Good |
| State Route 36 over Gold Run Creek | 1964 | 10,300 | Good |
| U.S. Highway 395 over Long Valley Creek | 1956 | 5,500 | Fair |
| U.S. Highway 395 over UP RR & BNSF Ry | 1969 | 5,500 | Fair |
| U.S. Highway 395 over Long Valley Creek Ovfl | 1969 | 5,500 | Fair |
All bridges nearby: Lassen County, CA bridge conditions · every bridge in Lassen County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.