Ia 37 over Mosquito Creek
Shelby County, Iowa · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Ia 37 over Mosquito Creek in Shelby County, Iowa, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 2001, making it 24 years old at the 2025 inventory.
- It carries about 1,300 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 78 of the 207 inventoried bridges in Shelby County rated good (37.7%); 18 (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 February 2023, on a 24-month routine inspection cycle.
- 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 → (41.77661, -95.41111)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 133 ft |
| Location | 0.6 mi. E of Jct. IA 191 |
| NBI structure number | 000000000047871 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | February 2023 |
| 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 Iowa department of transportation.
Busiest bridges in Shelby County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 59 over Drainage Ditch | 1966 | 5,000 | Fair |
| US 59 over Drainage Ditch | 1970 | 4,940 | Fair |
| US 59 over West Nishnabotna River | 1970 | 4,940 | Fair |
| US 59 over Jensen Creek | 1968 | 4,680 | Fair |
| Ia 44 over West Nishnabotna River | 1978 | 3,960 | Fair |
| US 59 over Lyon Creek | 1970 | 3,240 | Fair |
All bridges nearby: Shelby County, IA bridge conditions · every bridge in Shelby County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.