CR 305 (mapes Rd) over Hartson Slough
Lassen County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- CR 305 (mapes Rd) over Hartson Slough in Lassen County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1978, making it 47 years old at the 2025 inventory.
- It carries about 100 vehicles a day (traffic count year 1976).
- Its listed owner is the county highway agency.
- It is one of 72 of the 108 inventoried bridges in Lassen County rated fair (66.7%); 8 (7.4%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- It was rated poor in the 2024 inventory and is now fair (deck 5 to 6, superstructure 4 to 5, substructure 5 to 6).
- Its most recent inspection on record is dated August 2024, on a 12-month routine inspection cycle.
- 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 → (40.32238, -120.36219)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 6 | Satisfactory condition |
| Superstructure | 4 | 5 | Fair condition |
| Substructure | 5 | 6 | Satisfactory condition |
Bridge details
| Structure | Timber stringer or multi-beam girder |
| Length | about 45 ft |
| Location | 0.4 Mi E/o Rd 303 |
| NBI structure number | 07C0040 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | August 2024 |
| Inspection interval (item 91) | 12 months |
| Scour (item 113) | U: unknown foundation, not evaluated for scour |
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.