SH 34 over Twin Lakes Canal
Franklin County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SH 34 over Twin Lakes Canal in Franklin County, Idaho, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1958, making it 67 years old at the 2025 inventory.
- It carries about 1,200 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 18 of the 23 inventoried bridges in Franklin County rated fair (78.3%); 2 (8.7%) 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 November 2024, 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 → (42.19122, -111.83325)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete frame |
| Length | about 25 ft |
| Location | 6.2 N. Preston |
| NBI structure number | 000000000013990 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 2024 |
| Inspection interval (item 91) | 24 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 Idaho department of transportation.
Busiest bridges in Franklin County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 91 over Cub River | 2006 | 8,600 | Fair |
| US 91 over Bear River | 2006 | 4,200 | Fair |
| SH 36 over Bear River | 2018 | 3,000 | Good |
| SH 34 over Bear River;riverdale Br | 1960 | 2,800 | Fair |
| US 91 over West Cache Canal | 1993 | 2,300 | Good |
| SH 36 over Bear River | 1960 | 1,300 | Fair |
All bridges nearby: Franklin County, ID bridge conditions · every bridge in Franklin County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.