NF-6639 RD
Carrying NF-6639 RD over BOULDER RIVER 041
35M S SPRINGDALE, Park, Montana
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
NF-6639 RD in Park, Montana sits above 27% of rated Montana bridges on inventory load rating (25 t), while its 1933 build year is earlier than 93% of Park's recorded-year cohort (124 bridges).
NF-6639 RD in Park, Montana is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1933, 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 MT:L34210004+06001
PRE-1950 · STEEL · SINGLE-SPAN · SUB-LED · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- PRE-1950 Pre-1950
- STEEL Steel
- 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: NF-6639 RD
The NF-6639 RD bridge in Park, Montana carries NF-6639 RD over BOULDER RIVER 041. It was built in 1933, making it 93 years old today. The structure is built primarily of steel and spans 1 section, stretching 30.2 meters (99 feet) end to end. Daily traffic averages 156 vehicles, placing it in the lower-traffic tier of Montana bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 6/9, substructure at 4/9. 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 NF-6639 RD compares
Age against the county: built in 1933, earlier than 115 of Park's 124 bridges with a recorded construction year (93%), against a county median build year of 1976. 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).
NF-6639 RD vs every rated Montana bridge
Inventory load rating (metric tons), FHWA NBI, this state
25 Top 73% higher than 27% 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.
Park inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 124 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
- 1933
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 30.2 m (99 ft)
- Deck Width
- 4.0 m (13 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 156 vehicles/day
- Structure Number
- L34210004+06001
Condition Analysis
- • The deck (driving surface) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
- • At 6/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • The substructure (piers and abutments) rates poor at 4/9, with advanced deterioration recorded on the latest inspection.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
NF-6639 RD 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 NF-6639 RD against other structures in Park 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 NF-6639 RD?
NF-6639 RD in Park, Montana has a deck rating of 5/9, superstructure rating of 6/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is NF-6639 RD inspected?
NF-6639 RD'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 156 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. NF-6639 RD 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 NF-6639 RD?
NF-6639 RD has an NBI inventory load rating of 24.5 metric tons.
Who is responsible for maintaining NF-6639 RD?
NF-6639 RD is owned and maintained by County Highway Agency.
How old is NF-6639 RD and does age affect safety?
NF-6639 RD was built in 1933, making it 93 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.