I 15 over Frontage Road
Clark County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I 15 over Frontage Road in Clark 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 1965 and reconstructed in 1990, making it 60 years old at the 2025 inventory.
- It carries about 3,700 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 25 of the 39 inventoried bridges in Clark County rated fair (64.1%); 5 (12.8%) 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.
View this bridge on a map → (44.33275, -112.17428)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 6 | Satisfactory condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete frame |
| Length | about 27 ft |
| Location | 2.0 S. Spencer |
| NBI structure number | 000000000011940 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Clark County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 15 over Beaver Creek | 1969 | 3,500 | Fair |
| I 15 over Frontage Road Gs | 1969 | 3,500 | Fair |
| I 15 over Beaver Creek | 1963 | 3,400 | Fair |
| I 15 Nbl & Sbl over Beaver Creek;s.dubois Br | 1965 | 3,400 | Fair |
| I 15 Nbl over Spencer Road Ic | 1969 | 1,850 | Fair |
| I 15 Sbl over Spencer Road Ic | 1969 | 1,850 | Fair |
All bridges nearby: Clark County, ID bridge conditions · every bridge in Clark County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.