ILL 147
Carrying ILL 147 over CEDAR CREEK
IN SIMPSON, Johnson, Illinois
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: ILL 147
The ILL 147 bridge in Johnson, Illinois carries ILL 147 over CEDAR CREEK. It was built in 1937, making it 89 years old today. It was last reconstructed in 1988, extending its service life. The structure is built primarily of steel continuous and spans 3 sections, stretching 37.9 meters (124 feet) end to end. Daily traffic averages 550 vehicles, placing it in the lower-traffic tier of Illinois bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 8/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in good condition. All reported major components score above the Poor range. Its NBI inventory load rating is 37.3 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How ILL 147 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 How the historical reference is calculated.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
- 1937
- Last Reconstructed
- 1988
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 37.9 m (124 ft)
- Deck Width
- 9.8 m (32 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 550 vehicles/day
- Structure Number
- 044002500000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates good at 8/9, with no significant deterioration on file.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
How to read this record
This page shows what the last federal inspection recorded, not whether ILL 147 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 147 against other structures in Johnson 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 147?
ILL 147 in Johnson, Illinois has a deck rating of 8/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is ILL 147 inspected?
ILL 147'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 550 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. ILL 147 is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for ILL 147?
ILL 147 has an NBI inventory load rating of 37.3 metric tons.
Who is responsible for maintaining ILL 147?
ILL 147 is owned and maintained by State Highway Agency.
How old is ILL 147 and does age affect safety?
ILL 147 was built in 1937, making it 89 years old and last reconstructed in 1988.
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.