IRR US018
Carrying IRR US018 over CREEK
DOUGLAS/CHARLES MIX CO LN, Douglas, South Dakota
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
IRR US018 in Douglas, South Dakota sits above 48% of rated South Dakota bridges on inventory load rating (26 t), while its 1961 build year is earlier than 59% of Douglas's recorded-year cohort (44 bridges).
IRR US018 in Douglas, South Dakota is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1961, 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 SD:000000022228179
INTERSTATE-ERA · CONCRETE · LONG-SPAN-RUN · SUB-LED · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- CONCRETE Concrete
- LONG-SPAN-RUN 5 spans
- 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 US018
The IRR US018 bridge in Douglas, South Dakota carries IRR US018 over CREEK. It was built in 1961, making it 65 years old today. The structure is built primarily of concrete continuous and spans 5 sections, stretching 32.2 meters (106 feet) end to end. Daily traffic averages 588 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 7/9, superstructure at 7/9, 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.
How IRR US018 compares
Age against the county: built in 1961, earlier than 26 of Douglas's 44 bridges with a recorded construction year (59%), against a county median build year of 1972. 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 US018 vs every rated South Dakota bridge
Inventory load rating (metric tons), FHWA NBI, this state
26 Top 52% higher than 48% 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.
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.
Douglas inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 44 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
- 1961
- Material
- Concrete Continuous
- Number of Spans
- 5
- Structure Length
- 32.2 m (106 ft)
- Deck Width
- 10.5 m (34 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 588 vehicles/day
- Structure Number
- 000000022228179
Condition Analysis
- • The deck (driving surface) rates good at 7/9, with no significant deterioration on file.
- • At 7/9, the superstructure (beams and supports above the deck) is in good shape and shows no significant wear.
- • The substructure (piers and abutments) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
IRR US018 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 US018 against other structures in Douglas 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 US018?
IRR US018 in Douglas, South Dakota has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is IRR US018 inspected?
IRR US018'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 588 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IRR US018 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 US018?
IRR US018 has an NBI inventory load rating of 25.8 metric tons.
Who is responsible for maintaining IRR US018?
IRR US018 is owned and maintained by State Highway Agency.
How old is IRR US018 and does age affect safety?
IRR US018 was built in 1961, making it 65 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.