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Rd 318 over Susan River

Lassen County, California · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

Rd 318 over Susan River in Lassen County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1975, making it 50 years old at the 2025 inventory.
It carries about 100 vehicles a day (traffic count year 1979).
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.
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.

Component ratings


Structure	Timber stringer or multi-beam girder
Length	about 59 ft
Location	1.7 Mi E/o Rd 305
NBI structure number	07C0077
Condition class	Fair

Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.

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