Road M1 over Eel River
Lake County, California · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Road M1 over Eel River in Lake County, California, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 3 (serious condition) on the 0-9 scale.
- It was built in 1971, making it 54 years old at the 2025 inventory.
- It carries about 350 vehicles a day (traffic count year 1992).
- It is one of 12 of the 131 inventoried bridges in Lake County rated poor (9.2%); 12 (9.2%) 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 August 2023, on a 12-month routine inspection cycle.
- 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 → (39.74274, -123.0448)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 3 | 3 | Serious condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Concrete multiple box beam |
| Length | about 302 ft |
| Location | 13 Miles NE Potter Valley |
| NBI structure number | 050854000001001 |
| Condition class | Poor |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | August 2023 |
| Inspection interval (item 91) | 12 months |
| Scour (item 113) | 4: foundations stable, field review says exposed foundations need protection |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Lake County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 53 over Seigler Creek | 1952 | 16,500 | Fair |
| State Route 29 over Kelsey Creek | 1966 | 12,100 | Good |
| State Route 29 over Adobe Creek | 1966 | 12,100 | Good |
| State Route 29 over Hill Creek | 1966 | 12,100 | Good |
| State Route 29 over Manning Creek | 1966 | 12,100 | Good |
| State Route 29 over Putah Creek | 2003 | 10,900 | Good |
All bridges nearby: Lake County, CA bridge conditions · every bridge in Lake County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.