170TH St over Des Moines River
Webster County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 170TH St over Des Moines River in Webster County, Iowa, 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 1979, making it 46 years old at the 2025 inventory.
- It carries about 3,132 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 55 of the 190 inventoried bridges in Webster County rated fair (28.9%); 48 (25.3%) 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 November 2022, on a 48-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 → (42.54354, -94.21745)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 584 ft |
| Location | 089291205 |
| NBI structure number | 000000000343345 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 2022 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Webster County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| 1ST Ave S over 21ST St & RR | 1968 | 9,860 | Fair |
| US 20 over Holliday Creek | 1986 | 9,800 | Good |
| US 20 over Drainage Ditch #4 | 1986 | 9,500 | Good |
| 5TH Ave over Drainage Ditch | 1955 | 8,894 | Poor |
| N 15TH St over Soldier Creek | 1974 | 8,798 | Poor |
| US 20 over Drainage Ditch 69 | 2011 | 7,900 | Good |
All bridges nearby: Webster County, IA bridge conditions · every bridge in Webster County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.