Nhs 7553;CAPITOL over Boise River
Ada County, Idaho · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Nhs 7553;CAPITOL over Boise River in Ada 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 1931 and reconstructed in 1992, making it 94 years old at the 2025 inventory.
- It carries about 16,500 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 165 of the 302 inventoried bridges in Ada County rated fair (54.6%); 3 (1.0%) 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: superstructure 7 to 6.
- Its most recent inspection on record is dated September 2024, on a 24-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- 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 → (43.60836, -116.20875)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 7 | 6 | Satisfactory condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete deck arch |
| Length | about 303 ft |
| Location | In Boise;capitol Blvd |
| NBI structure number | 000000000021445 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Ada County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 84 Ebl & Wbl over Ridenbaugh Canal | 1966 | 144,500 | Fair |
| I 84 over Ten Mile Creek | 1965 | 131,000 | Fair |
| I 184B Ebl & Wbl over S7403;UPRR;FRANKLIN Ic | 2001 | 76,500 | Good |
| I 184B Ebl & Wbl over S7073;CANAL;COLE Rd | 2001 | 76,500 | Fair |
| I 184 Ebl over I 84 Wbl | 2001 | 68,500 | Good |
| SH 55;EAGLE Road over I 84 Eb-wb;eagle Rd Ic | 1990 | 58,000 | Fair |
All bridges nearby: Ada County, ID bridge conditions · every bridge in Ada County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.