Tr 20 over Rocky Run Diversion
Adams County, Illinois · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Tr 20 over Rocky Run Diversion in Adams 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 1984, making it 41 years old at the 2025 inventory.
- It carries about 100 vehicles a day (traffic count year 2024).
- Its listed owner is a town or township highway agency.
- It is one of 129 of the 317 inventoried bridges in Adams County rated good (40.7%); 19 (6.0%) 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 January 2022, 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 → (40.14047, -91.41074)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 122 ft |
| Location | 2.6 Mi NW Marceline |
| NBI structure number | 001329200000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | January 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 Illinois department of transportation.
Busiest bridges in Adams County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Fai 172 over Fall Creek | 1982 | 13,100 | Good |
| Ill 104 over Fai 172 | 1976 | 12,000 | Fair |
| Fau 7810 (il 96) over Emery Creek | 2016 | 11,300 | Good |
| Ill 96 over Curtis Creek | 2003 | 10,500 | Fair |
| Fai 172 over Austin Creek | 1982 | 9,750 | Fair |
| US 24(WB)/ Broadwa over Miss. R/streets/bnrr | 1986 | 8,600 | Fair |
All bridges nearby: Adams County, IL bridge conditions · every bridge in Adams County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.