Tr 170 over Trib North Lake
Piatt County, Illinois · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Tr 170 over Trib North Lake in Piatt County, Illinois, 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 2019, making it 6 years old at the 2025 inventory.
- It carries about 50 vehicles a day (traffic count year 2020).
- Its listed owner is a town or township highway agency.
- It is one of 137 of the 246 inventoried bridges in Piatt County rated good (55.7%); 14 (5.7%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (good), but component ratings moved: deck 8 to 7, superstructure 8 to 7, substructure 8 to 7.
- Its most recent inspection on record is dated February 2025, on a 48-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 → (39.83413, -88.49049)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 8 | 7 | Good condition |
| Superstructure | 8 | 7 | Good condition |
| Substructure | 8 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 69 ft |
| Location | 3.0 Mi NW Atwood |
| NBI structure number | 074331200000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | February 2025 |
| 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 Illinois department of transportation.
Busiest bridges in Piatt County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-74 over Madden Creek Trib | 1971 | 22,800 | Good |
| I-74 over Madden Creek Trib | 1971 | 22,800 | Fair |
| I-74 over Stream | 1970 | 21,500 | Fair |
| I-72 over Stream | 1976 | 11,400 | Fair |
| I-72 over Wolf Run | 1976 | 11,400 | Fair |
| I-74 (EB) over S Branch Salt Creek | 1970 | 10,750 | Fair |
All bridges nearby: Piatt County, IL bridge conditions · every bridge in Piatt County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.