X Ave over Onion Creek
Boone County, Iowa · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- X Ave over Onion Creek in Boone County, Iowa, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 9 (excellent condition) on the 0-9 scale.
- It was built in 2023, making it 2 years old at the 2025 inventory.
- It carries about 50 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 38 of the 134 inventoried bridges in Boone County rated good (28.4%); 38 (28.4%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (42.05634, -93.71805)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 9 | Excellent condition |
| Superstructure | 9 | Excellent condition |
| Substructure | 9 | Excellent condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 81 ft |
| Location | 084252502 |
| NBI structure number | 000000000077691 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Boone County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 30 over Noah Creek | 1962 | 8,800 | Fair |
| US 30 over Honey Creek | 1962 | 8,800 | Fair |
| US 30 & 169 over East Beaver Creek | 1962 | 5,900 | Good |
| Ia 17 over Big Creek | 1961 | 5,300 | Fair |
| Ia 17 over US 30 | 1968 | 4,960 | Fair |
| US 30 EB over Des Moines River | 1963 | 4,400 | Fair |
All bridges nearby: Boone County, IA bridge conditions · every bridge in Boone County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.