ILL 161
Carrying ILL 161 over SILVER CREEK
2.2 M E JCT 158, St. Clair, Illinois
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: ILL 161
The ILL 161 bridge in St. Clair, Illinois carries ILL 161 over SILVER CREEK. It was built in 1932, making it 94 years old today. It was last reconstructed in 1992, extending its service life. The structure is built primarily of steel continuous and spans 6 sections, stretching 94.9 meters (311 feet) end to end. Daily traffic averages 4,950 vehicles, placing it in the moderately-trafficked tier of Illinois bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in fair condition. No reported major component scores in the Poor range under the current federal condition thresholds. Its NBI inventory load rating is 31.8 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How ILL 161 compares
Live comparison across Illinois.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1932
- Last Reconstructed
- 1992
- Material
- Steel Continuous
- Number of Spans
- 6
- Structure Length
- 94.9 m (311 ft)
- Deck Width
- 10.7 m (35 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 4,950 vehicles/day
- Structure Number
- 082009500000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 6/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • The substructure (piers and abutments) rates good at 7/9, with no significant deterioration on file.
How to read this record
This page shows what the last federal inspection recorded, not whether ILL 161 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare ILL 161 against other structures in St. Clair and across Illinois. Illinois bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for ILL 161?
ILL 161 in St. Clair, Illinois has a deck rating of 6/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is ILL 161 inspected?
ILL 161's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 4,950 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. ILL 161 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for ILL 161?
ILL 161 has an NBI inventory load rating of 31.8 metric tons.
Who is responsible for maintaining ILL 161?
ILL 161 is owned and maintained by State Highway Agency.
How old is ILL 161 and does age affect safety?
ILL 161 was built in 1932, making it 94 years old and last reconstructed in 1992.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.