Alpine Rd over Forest Hills Rd
Winnebago County, Illinois · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Alpine Rd over Forest Hills Rd in Winnebago County, Illinois, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1972 and reconstructed in 2021, making it 53 years old at the 2025 inventory.
- It carries about 16,700 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 291 of the 465 inventoried bridges in Winnebago County rated fair (62.6%); 32 (6.9%) are rated poor.
- 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 → (42.32124, -89.02898)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 8 | Very good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 251 ft |
| Location | 0.2 Mi S Windsor Rd |
| NBI structure number | 101306800000000 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.
Busiest bridges in Winnebago County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-39 & US 20 over Madigan Creek | 1963 | 50,900 | Fair |
| I-90 N B over US 20 Br | 2009 | 36,350 | Good |
| I-90 S B over US 20 Br | 2009 | 36,350 | Good |
| US 20 W B over Ill 251 (11TH St) | 1960 | 36,000 | Fair |
| I-90 over Stream | 1958 | 34,100 | Good |
| US 20 E B over Kishwaukee St. | 1960 | 32,000 | Fair |
All bridges nearby: Winnebago County, IL bridge conditions · every bridge in Winnebago County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.