I-355 NB & SB
Carrying I-355 NB & SB over FINLEY RD & RAMP
0.8 M.N. OF US-34, DuPage, Illinois
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
I-355 NB & SB in DuPage, Illinois sits above 92% of rated Illinois bridges on inventory load rating (50 t), while its 1989 build year is earlier than 39% of DuPage's recorded-year cohort (344 bridges).
I-355 NB & SB in DuPage, Illinois is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1989, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. The lowest applicable rating sets the federal condition category, so this Fair result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure IL:022996600000000
LATE-CENTURY · STEEL · LONG-SPAN-RUN · TIED-CTRL · HEAVY-ADT · HEAVY-LOAD · CAT-FAIR
- LATE-CENTURY 1980–1999
- STEEL Steel
- LONG-SPAN-RUN 4 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- HEAVY-LOAD Heavy load
- CAT-FAIR Fair
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Structural health score
A composite of the deck, superstructure, and substructure NBI condition ratings plus the inventory load rating, benchmarked against the full national bridge corpus, distinct from the Good/Fair/Poor category above.
Bridge Snapshot: I-355 NB & SB
The I-355 NB & SB bridge in DuPage, Illinois carries I-355 NB & SB over FINLEY RD & RAMP. It was built in 1989, making it 37 years old today. The structure is built primarily of steel and spans 4 sections, stretching 160.3 meters (526 feet) end to end. Daily traffic averages 102,800 vehicles, placing it in the heavily-trafficked tier of Illinois bridges. It is owned and maintained by State Toll Authority.
The latest FHWA inspection places the weakest component in fair condition (see the full component ratings below). None of this bridge's reported major components fall into the Poor condition range.
How I-355 NB & SB compares
Age against the county: built in 1989, earlier than 134 of DuPage's 344 bridges with a recorded construction year (39%), against a county median build year of 1988. This is one of the newer structures in its county.
Live comparison across Illinois bridges with a recorded inventory load rating (26,904 of 26,928 rated).
I-355 NB & SB vs every rated Illinois bridge
Inventory load rating (metric tons), FHWA NBI, this state
50 Top 8% higher than 92% of 26,904 bridges
rated Illinois bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
DuPage inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 344 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1989
- Material
- Steel
- Number of Spans
- 4
- Structure Length
- 160.3 m (526 ft)
- Deck Width
- 42.5 m (139 ft)
- Owner
- State Toll Authority
- Avg Daily Traffic
- 102,800 vehicles/day
- Structure Number
- 022996600000000
Condition Analysis
- • The deck (driving surface) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • At 6/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether I-355 NB & SB 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 I-355 NB & SB against other structures in DuPage 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 I-355 NB & SB?
I-355 NB & SB in DuPage, Illinois has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is I-355 NB & SB inspected?
I-355 NB & SB'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 102,800 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. I-355 NB & SB 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 I-355 NB & SB?
I-355 NB & SB has an NBI inventory load rating of 49.6 metric tons.
Who is responsible for maintaining I-355 NB & SB?
I-355 NB & SB is owned and maintained by State Toll Authority.
How old is I-355 NB & SB and does age affect safety?
I-355 NB & SB was built in 1989, making it 37 years old.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.