IRR ROUTE 46
Carrying IRR ROUTE 46 over BIG SANDY CREEK
11 KM NNW OF BOX ELDER, Hill, Montana
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
IRR ROUTE 46 in Hill, Montana sits above 26% of rated Montana bridges on inventory load rating (24 t), while its 1963 build year is earlier than 78% of Hill's recorded-year cohort (46 bridges).
IRR ROUTE 46 in Hill, Montana is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1963, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 2. 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 MT:0000C59205B0922
INTERSTATE-ERA · CONCRETE · SINGLE-SPAN · SUB-LED · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- CONCRETE Concrete
- SINGLE-SPAN Single span
- SUB-LED Substructure-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: IRR ROUTE 46
The IRR ROUTE 46 bridge in Hill, Montana carries IRR ROUTE 46 over BIG SANDY CREEK. It was built in 1963, making it 63 years old today. The structure is built primarily of concrete and spans 1 section, stretching 7.7 meters (25 feet) end to end. Daily traffic averages 100 vehicles, placing it in the lower-traffic tier of Montana bridges. It is owned and maintained by Bureau of Indian Affairs.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 4/9, substructure at 2/9. The weakest component sits in critical condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed.
How IRR ROUTE 46 compares
Age against the county: built in 1963, earlier than 36 of Hill's 46 bridges with a recorded construction year (78%), against a county median build year of 1984. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Montana bridges with a recorded inventory load rating (5,144 of 5,224 rated).
IRR ROUTE 46 vs every rated Montana bridge
Inventory load rating (metric tons), FHWA NBI, this state
24 Top 74% higher than 26% of 5,144 bridges
rated Montana 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.
Hill inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 46 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
- 1963
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 7.7 m (25 ft)
- Deck Width
- 7.8 m (26 ft)
- Owner
- Bureau of Indian Affairs
- Avg Daily Traffic
- 100 vehicles/day
- Structure Number
- 0000C59205B0922
Condition Analysis
- • The deck (driving surface) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) rates poor at 4/9, with advanced deterioration recorded on the latest inspection.
- • At 2/9, the substructure (piers and abutments) is in critical shape, with severe wear recorded for this vintage.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
IRR ROUTE 46 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 IRR ROUTE 46 against other structures in Hill and across Montana. Montana 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 IRR ROUTE 46?
IRR ROUTE 46 in Hill, Montana has a deck rating of 5/9, superstructure rating of 4/9, and substructure rating of 2/9 on the FHWA's 0–9 scale.
How often is IRR ROUTE 46 inspected?
IRR ROUTE 46'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 100 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IRR ROUTE 46 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 IRR ROUTE 46?
IRR ROUTE 46 has an NBI inventory load rating of 24.4 metric tons.
Who is responsible for maintaining IRR ROUTE 46?
IRR ROUTE 46 is owned and maintained by Bureau of Indian Affairs.
How old is IRR ROUTE 46 and does age affect safety?
IRR ROUTE 46 was built in 1963, making it 63 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.