IRR US012
Carrying IRR US012 over BR SNAKE CK
1.7 NW JCT SD 20, Corson, South Dakota
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
IRR US012 in Corson, South Dakota sits above 45% of rated South Dakota bridges on inventory load rating (25 t), while its 1965 build year is earlier than 53% of Corson's recorded-year cohort (49 bridges).
IRR US012 in Corson, South Dakota is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1965, it carries 1 rated component 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 SD:000000016687258
INTERSTATE-ERA · CONCRETE · MULTI-SPAN · CULVERT-LED · ARTERIAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- CONCRETE Concrete
- MULTI-SPAN 2 spans
- CULVERT-LED Culvert-led
- ARTERIAL-ADT Arterial 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 US012
The IRR US012 bridge in Corson, South Dakota carries IRR US012 over BR SNAKE CK. It was built in 1965, making it 61 years old today. The structure is built primarily of concrete continuous and spans 2 sections, stretching 6.5 meters (21 feet) end to end. Daily traffic averages 1,102 vehicles, placing it in the moderately-trafficked tier of South Dakota bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show culvert 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 IRR US012 compares
Age against the county: built in 1965, earlier than 26 of Corson's 49 bridges with a recorded construction year (53%), against a county median build year of 1968. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across South Dakota bridges with a recorded inventory load rating (5,886 of 5,887 rated).
IRR US012 vs every rated South Dakota bridge
Inventory load rating (metric tons), FHWA NBI, this state
25 Top 55% higher than 45% of 5,886 bridges
rated South Dakota 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.
Corson inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 49 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
- 1965
- Material
- Concrete Continuous
- Number of Spans
- 2
- Structure Length
- 6.5 m (21 ft) 0
- Owner
- State Highway Agency
- Avg Daily Traffic
- 1,102 vehicles/day
- Structure Number
- 000000016687258
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗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 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 1,102 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 24.9 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 1965, making it 61 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.