S. Dewey Ave over Mill Slough
Canyon County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S. Dewey Ave over Mill Slough in Canyon County, Idaho, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1980, making it 45 years old at the 2025 inventory.
- It carries about 440 vehicles a day (traffic count year 2023).
- Its listed owner is a city or municipal highway agency.
- It is one of 199 of the 291 inventoried bridges in Canyon County rated fair (68.4%); 6 (2.1%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its class is unchanged from 2024 (fair), but component ratings moved: substructure 7 to 6, superstructure 6 to 7.
- 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 → (43.70481, -116.61966)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 7 | Good condition |
| Substructure | 7 | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete tee beam |
| Length | about 27 ft |
| Location | at Middleton Scl |
| NBI structure number | 000000000027310 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | November 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Canyon County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 84 Wbl & Ebl over I 84B ;garrity Blvd Ic | 2011 | 111,000 | Good |
| I 84 Ebl & Wbl over Uprr;east Lateral Canal | 2021 | 104,000 | Good |
| I 84 Ebl Wbl over Northside Blvd Ic | 2021 | 84,500 | Good |
| I 84 Ebl Wbl over Sma 7923; Linden Road Gs | 2022 | 68,000 | Good |
| I84 Ebl Wbl over Notus Canal | 2022 | 68,000 | Good |
| I 84 ;US 20-26 over Stp 7773;10TH Ave Ic | 1983 | 58,000 | Fair |
All bridges nearby: Canyon County, ID bridge conditions · every bridge in Canyon County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.