THAYER ROAD
Carrying THAYER ROAD over NIPPERSINK CREEK
0.3 MI W OF IL 47, McHenry, Illinois
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
THAYER ROAD in McHenry, Illinois sits above 13% of rated Illinois bridges on inventory load rating (25 t), while its 1975 build year is earlier than 64% of McHenry's recorded-year cohort (227 bridges).
THAYER ROAD in McHenry, Illinois is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1975, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 3. The lowest applicable rating sets the federal condition category, so this Poor 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:056311500000000
INTERSTATE-ERA · CONCRETE · MULTI-SPAN · TIED-CTRL · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- CONCRETE Concrete
- MULTI-SPAN 3 spans
- TIED-CTRL Tied control
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-POOR Poor
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: THAYER ROAD
The THAYER ROAD bridge in McHenry, Illinois carries THAYER ROAD over NIPPERSINK CREEK. It was built in 1975, making it 51 years old today. The structure is built primarily of concrete and spans 3 sections, stretching 28.0 meters (92 feet) end to end. Daily traffic averages 800 vehicles, placing it in the lower-traffic tier of Illinois bridges. It is owned and maintained by Town/Township Highway Agency.
The latest FHWA inspection records show a deck rating of 3/9, superstructure at 3/9, substructure at 7/9. The weakest component sits in poor condition. Because at least one major component scores 4 or lower, this bridge falls in FHWA's Poor condition category. That category is not a closure order.
How THAYER ROAD compares
Age against the county: built in 1975, earlier than 145 of McHenry's 227 bridges with a recorded construction year (64%), against a county median build year of 1985. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Illinois bridges with a recorded inventory load rating (26,904 of 26,928 rated).
THAYER ROAD vs every rated Illinois bridge
Inventory load rating (metric tons), FHWA NBI, this state
25 Top 87% higher than 13% 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.
McHenry inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 227 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
- 1975
- Material
- Concrete
- Number of Spans
- 3
- Structure Length
- 28.0 m (92 ft)
- Deck Width
- 8.1 m (27 ft)
- Owner
- Town/Township Highway Agency
- Avg Daily Traffic
- 800 vehicles/day
- Structure Number
- 056311500000000
Condition Analysis
- • The deck (driving surface) is in poor condition (3/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • The superstructure (beams and supports above the deck) is in poor condition (3/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
THAYER ROAD is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare THAYER ROAD against other structures in McHenry 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 THAYER ROAD?
THAYER ROAD in McHenry, Illinois has a deck rating of 3/9, superstructure rating of 3/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is THAYER ROAD inspected?
THAYER ROAD'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 800 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. THAYER ROAD is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for THAYER ROAD?
THAYER ROAD has an NBI inventory load rating of 25.3 metric tons.
Who is responsible for maintaining THAYER ROAD?
THAYER ROAD is owned and maintained by Town/Township Highway Agency.
How old is THAYER ROAD and does age affect safety?
THAYER ROAD was built in 1975, making it 51 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.
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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.