6TH St.sw. over US 30
Linn County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 6TH St.sw. over US 30 in Linn County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1975, making it 50 years old at the 2025 inventory.
- It carries about 10,989 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 295 of the 511 inventoried bridges in Linn County rated fair (57.7%); 34 (6.7%) 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 June 2023, on a 24-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 → (41.92677, -91.67639)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 280 ft |
| Location | 0.3 Mi W. of Jct. I-380 |
| NBI structure number | 000000000600597 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | June 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Linn County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-380 over E and F Ave NW Cedar Rvr | 1979 | 57,600 | Fair |
| SB I-380 over Cc RR & Ash Pit | 1979 | 41,000 | Fair |
| NB I-380 over Cc RR | 1980 | 38,800 | Fair |
| SB I-380 over Cc RR | 1980 | 38,800 | Fair |
| NB I-380 over H Ave NE | 1980 | 38,800 | Fair |
| SB I-380 over H Ave NE | 1980 | 38,800 | Good |
All bridges nearby: Linn County, IA bridge conditions · every bridge in Linn County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.