STH 55
Carrying STH 55 over POPPLE RIVER
11.0M N JCT STH 32 TO N, Forest, Wisconsin
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: STH 55
The STH 55 bridge in Forest, Wisconsin carries STH 55 over POPPLE RIVER. It was built in 2001, making it 25 years old today. The structure is built primarily of concrete and spans 1 section, stretching 8.3 meters (27 feet) end to end. Daily traffic averages 160 vehicles, placing it in the lower-traffic tier of Wisconsin bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, 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 40.5 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How STH 55 compares
Live comparison across Wisconsin.
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 How the historical reference is calculated.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
- 2001
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 8.3 m (27 ft)
- Deck Width
- 11.0 m (36 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 160 vehicles/day
- Structure Number
- B21001700000000
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) is in good condition (7/9), showing no significant deterioration.
How to read this record
This page shows what the last federal inspection recorded, not whether STH 55 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 STH 55 against other structures in Forest and across Wisconsin. Wisconsin 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 STH 55?
STH 55 in Forest, Wisconsin has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is STH 55 inspected?
STH 55'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 160 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. STH 55 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 STH 55?
STH 55 has an NBI inventory load rating of 40.5 metric tons.
Who is responsible for maintaining STH 55?
STH 55 is owned and maintained by State Highway Agency.
How old is STH 55 and does age affect safety?
STH 55 was built in 2001, making it 25 years old.
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.