State Route 20 over Interstate 5
Colusa County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- State Route 20 over Interstate 5 in Colusa County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1971, making it 54 years old at the 2025 inventory.
- It carries about 5,800 vehicles a day (traffic count year 2013).
- Its listed owner is the state highway agency.
- It is one of 100 of the 213 inventoried bridges in Colusa County rated fair (46.9%); 12 (5.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: deck 6 to 7, substructure 7 to 8.
- Its most recent inspection on record is dated January 2025, on a 24-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 → (39.16643, -122.15036)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 8 | Very good condition |
Bridge details
| Structure | Continuous prestressed concrete multiple box beam |
| Length | about 284 ft |
| Location | 03-col-020-r22.09 |
| NBI structure number | 15 0078 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 2025 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Colusa County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Interstate 5 over Hillgate Road | 1957 | 35,000 | Good |
| Interstate 5 over Brush Creek | 1967 | 35,000 | Good |
| Interstate 5 over Cortina Creek Overflow | 1946 | 33,000 | Good |
| Interstate 5 over Farm Land Drain | 1968 | 30,000 | Fair |
| Interstate 5 over South Branch Sand Creek | 1967 | 29,500 | Good |
| Interstate 5 over Petroleum Creek | 1967 | 18,000 | Fair |
All bridges nearby: Colusa County, CA bridge conditions · every bridge in Colusa County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.