IRR - S 358
Carrying IRR - S 358 over TWO MEDICINE RIVER
12M S CUT BANK, Pondera, Montana
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: IRR - S 358
The IRR - S 358 bridge in Pondera, Montana carries IRR - S 358 over TWO MEDICINE RIVER. It was built in 1968, making it 58 years old today. The structure is built primarily of prestressed concrete and spans 5 sections, stretching 96.9 meters (318 feet) end to end. Daily traffic averages 242 vehicles, placing it in the lower-traffic tier of Montana bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 7/9, 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. Its NBI inventory load rating is 22.7 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How IRR - S 358 compares
Live comparison across Montana.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1968
- Material
- Prestressed Concrete
- Number of Spans
- 5
- Structure Length
- 96.9 m (318 ft)
- Deck Width
- 10.9 m (36 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 242 vehicles/day
- Structure Number
- S00358016+08321
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 4/9, the deck (driving surface) is in poor shape, with advanced wear flagged for priority repair.
- • At 7/9, the superstructure (beams and supports above the deck) is in good shape and shows no significant wear.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
How to read this record
IRR - S 358 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 - S 358 against other structures in Pondera 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 - S 358?
IRR - S 358 in Pondera, Montana has a deck rating of 4/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is IRR - S 358 inspected?
IRR - S 358'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 242 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IRR - S 358 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 - S 358?
IRR - S 358 has an NBI inventory load rating of 22.7 metric tons.
Who is responsible for maintaining IRR - S 358?
IRR - S 358 is owned and maintained by State Highway Agency.
How old is IRR - S 358 and does age affect safety?
IRR - S 358 was built in 1968, making it 58 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.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.