Tr 170 over Macoupin Crk
Macoupin County, Illinois · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Tr 170 over Macoupin Crk in Macoupin County, Illinois, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1900, making it 125 years old at the 2025 inventory.
- It carries about 50 vehicles a day (traffic count year 2021).
- Its listed owner is a town or township highway agency.
- It is one of 40 of the 240 inventoried bridges in Macoupin County rated poor (16.7%); 40 (16.7%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated February 2023, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (39.20685, -90.00062)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 4 | 4 | Poor condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel through truss |
| Length | about 140 ft |
| Location | Beaver Dam St. Park |
| NBI structure number | 059311100000000 |
| Condition class | Poor |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | February 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.
Busiest bridges in Macoupin County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Fai 55 SB over Tr 439 | 1973 | 15,200 | Fair |
| Fai 55 NB over Tr 439 | 1973 | 15,200 | Fair |
| Ill 108 over Drainage Ditch | 1933 | 6,950 | Fair |
| Ill 4 over East Fork Creek | 1957 | 4,800 | Fair |
| Il 111 over Little Piasa Creek | 1929 | 4,550 | Fair |
| Il 111 over S Br Little Piasa CR | 1929 | 4,550 | Fair |
All bridges nearby: Macoupin County, IL bridge conditions · every bridge in Macoupin County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.