IRR US012
Carrying IRR US012 over HAY CK
1.3 E OF MORRISTOWN, Corson, South Dakota
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: IRR US012
The IRR US012 bridge in Corson, South Dakota carries IRR US012 over HAY CK. It was built in 1949, making it 77 years old today. The structure is built primarily of steel and spans 3 sections, stretching 43.7 meters (143 feet) end to end. Daily traffic averages 436 vehicles, placing it in the lower-traffic tier of South Dakota bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 4/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules. Its NBI inventory load rating is 28.2 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How IRR US012 compares
Live comparison across South Dakota.
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 How the historical reference is calculated.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
- 1949
- Material
- Steel
- Number of Spans
- 3
- Structure Length
- 43.7 m (143 ft)
- Deck Width
- 9.8 m (32 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 436 vehicles/day
- Structure Number
- 000000016154005
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), 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.
- • At 4/9, the substructure (piers and abutments) is in poor shape, with advanced wear flagged for priority repair.
How to read this record
IRR US012 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 US012 against other structures in Corson and across South Dakota. South Dakota 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 US012?
IRR US012 in Corson, South Dakota has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is IRR US012 inspected?
IRR US012'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 436 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IRR US012 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 US012?
IRR US012 has an NBI inventory load rating of 28.2 metric tons.
Who is responsible for maintaining IRR US012?
IRR US012 is owned and maintained by State Highway Agency.
How old is IRR US012 and does age affect safety?
IRR US012 was built in 1949, making it 77 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.