3425 RD Mile 21
Carrying 3425 RD Mile 21 over BIG HILL CREEK
0.3E OF LIBERTY, Montgomery, Kansas
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
3425 RD Mile 21 in Montgomery, Kansas sits above 38% of rated Kansas bridges on inventory load rating (23 t), while its 1956 build year is earlier than 67% of Montgomery's recorded-year cohort (326 bridges).
3425 RD Mile 21 in Montgomery, Kansas is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1956, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. 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 KS:000000000630540
INTERSTATE-ERA · CONCRETE · LONG-SPAN-RUN · DECK-LED · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- CONCRETE Concrete
- LONG-SPAN-RUN 4 spans
- DECK-LED Deck-led
- 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: 3425 RD Mile 21
The 3425 RD Mile 21 bridge in Montgomery, Kansas carries 3425 RD Mile 21 over BIG HILL CREEK. It was built in 1956, making it 70 years old today. The structure is built primarily of concrete continuous and spans 4 sections, stretching 81.4 meters (267 feet) end to end. Daily traffic averages 516 vehicles, placing it in the lower-traffic tier of Kansas bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 6/9, substructure at 6/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed.
How 3425 RD Mile 21 compares
Age against the county: built in 1956, earlier than 219 of Montgomery's 326 bridges with a recorded construction year (67%), against a county median build year of 1975. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Kansas bridges with a recorded inventory load rating (24,893 of 24,894 rated).
3425 RD Mile 21 vs every rated Kansas bridge
Inventory load rating (metric tons), FHWA NBI, this state
23 Top 62% higher than 38% of 24,893 bridges
rated Kansas 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.
Montgomery inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 326 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
- 1956
- Material
- Concrete Continuous
- Number of Spans
- 4
- Structure Length
- 81.4 m (267 ft)
- Deck Width
- 7.9 m (26 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 516 vehicles/day
- Structure Number
- 000000000630540
Condition Analysis
- • The deck (driving surface) rates poor at 4/9, with advanced deterioration recorded on the latest inspection.
- • 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
3425 RD Mile 21 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 3425 RD Mile 21 against other structures in Montgomery and across Kansas. Kansas 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 3425 RD Mile 21?
3425 RD Mile 21 in Montgomery, Kansas has a deck rating of 4/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is 3425 RD Mile 21 inspected?
3425 RD Mile 21'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 516 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 3425 RD Mile 21 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 3425 RD Mile 21?
3425 RD Mile 21 has an NBI inventory load rating of 22.9 metric tons.
Who is responsible for maintaining 3425 RD Mile 21?
3425 RD Mile 21 is owned and maintained by County Highway Agency.
How old is 3425 RD Mile 21 and does age affect safety?
3425 RD Mile 21 was built in 1956, making it 70 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.
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.