172ND ST
Carrying 172ND ST over OKOBOJO CK
4N & 2.9W AGAR, Sully, South Dakota
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
172ND ST in Sully, South Dakota sits above 27% of rated South Dakota bridges on inventory load rating (24 t), while its 1912 build year is earlier than 97% of Sully's recorded-year cohort (31 bridges).
172ND ST in Sully, South Dakota is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1912, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 5. The lowest applicable rating sets the federal condition category, so this Fair 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:000000060281000
PRE-1950 · STEEL · SINGLE-SPAN · SUB-LED · TRACE-ADT · STANDARD-LOAD · CAT-FAIR
- PRE-1950 Pre-1950
- STEEL Steel
- SINGLE-SPAN Single span
- SUB-LED Substructure-led
- TRACE-ADT Trace ADT
- STANDARD-LOAD Standard load
- CAT-FAIR Fair
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: 172ND ST
The 172ND ST bridge in Sully, South Dakota carries 172ND ST over OKOBOJO CK. It was built in 1912, making it 114 years old today. It was last reconstructed in 1967, extending its service life. The structure is built primarily of steel and spans 1 section, stretching 9.3 meters (31 feet) end to end. Daily traffic averages 25 vehicles, placing it in the lower-traffic tier of South Dakota bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 8/9, superstructure at 7/9, substructure at 5/9. The weakest component sits in fair condition. No reported major component scores in the Poor range under the current federal condition thresholds.
How 172ND ST compares
Age against the county: built in 1912, earlier than 30 of Sully's 31 bridges with a recorded construction year (97%), against a county median build year of 1974. 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).
172ND ST vs every rated South Dakota bridge
Inventory load rating (metric tons), FHWA NBI, this state
24 Top 73% higher than 27% 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.
Sully inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 31 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
- 1912
- Last Reconstructed
- 1967
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 9.3 m (31 ft)
- Deck Width
- 7.3 m (24 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 25 vehicles/day
- Structure Number
- 000000060281000
Condition Analysis
- • The deck (driving surface) rates good at 8/9, with no significant deterioration on file.
- • The superstructure (beams and supports above the deck) rates good at 7/9, with no significant deterioration on file.
- • The substructure (piers and abutments) rates fair at 5/9, minor deterioration that routine maintenance should address.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether 172ND ST is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare 172ND ST against other structures in Sully 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 172ND ST?
172ND ST in Sully, South Dakota has a deck rating of 8/9, superstructure rating of 7/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.
How often is 172ND ST inspected?
172ND ST'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 25 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 172ND ST is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 172ND ST?
172ND ST has an NBI inventory load rating of 23.7 metric tons.
Who is responsible for maintaining 172ND ST?
172ND ST is owned and maintained by County Highway Agency.
How old is 172ND ST and does age affect safety?
172ND ST was built in 1912, making it 114 years old and last reconstructed in 1967.
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.