478TH AVE HWY 121
Carrying 478TH AVE HWY 121 over SLIP-UP CREEK
4E & 0.9S BALTIC, Minnehaha, South Dakota
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
478TH AVE HWY 121 in Minnehaha, South Dakota sits above 71% of rated South Dakota bridges on inventory load rating (36 t), while its 2013 build year is earlier than 12% of Minnehaha's recorded-year cohort (393 bridges).
478TH AVE HWY 121 in Minnehaha, South Dakota is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 2013, it carries 1 rated component on the inspecting agency's 0-9 scale, and its weakest reported component scores 7. The lowest applicable rating sets the federal condition category, so this Good 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:000000050240069
POST-2000 · CONCRETE · MULTI-SPAN · CULVERT-LED · ARTERIAL-ADT · STANDARD-LOAD · CAT-GOOD
- POST-2000 2000+
- CONCRETE Concrete
- MULTI-SPAN 3 spans
- CULVERT-LED Culvert-led
- ARTERIAL-ADT Arterial ADT
- STANDARD-LOAD Standard load
- CAT-GOOD Good
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: 478TH AVE HWY 121
The 478TH AVE HWY 121 bridge in Minnehaha, South Dakota carries 478TH AVE HWY 121 over SLIP-UP CREEK. It was built in 2013, making it 13 years old today. The structure is built primarily of concrete continuous and spans 3 sections, stretching 12.7 meters (42 feet) end to end. Daily traffic averages 1,116 vehicles, placing it in the moderately-trafficked tier of South Dakota bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show culvert at 7/9. The weakest component sits in good condition. No reported major component scores in the Poor range under the current federal condition thresholds.
How 478TH AVE HWY 121 compares
Age against the county: built in 2013, earlier than 49 of Minnehaha's 393 bridges with a recorded construction year (12%), against a county median build year of 1990. This is one of the newer structures in its county.
Live comparison across South Dakota bridges with a recorded inventory load rating (5,886 of 5,887 rated).
478TH AVE HWY 121 vs every rated South Dakota bridge
Inventory load rating (metric tons), FHWA NBI, this state
36 Top 29% higher than 71% 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.
Minnehaha inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 393 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
- 2013
- Material
- Concrete Continuous
- Number of Spans
- 3
- Structure Length
- 12.7 m (42 ft) 0
- Owner
- County Highway Agency
- Avg Daily Traffic
- 1,116 vehicles/day
- Structure Number
- 000000050240069
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 478TH AVE HWY 121 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 478TH AVE HWY 121 against other structures in Minnehaha 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 478TH AVE HWY 121?
478TH AVE HWY 121 in Minnehaha, South Dakota on the FHWA's 0–9 scale.
How often is 478TH AVE HWY 121 inspected?
478TH AVE HWY 121'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 1,116 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 478TH AVE HWY 121 is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 478TH AVE HWY 121?
478TH AVE HWY 121 has an NBI inventory load rating of 36.4 metric tons.
Who is responsible for maintaining 478TH AVE HWY 121?
478TH AVE HWY 121 is owned and maintained by County Highway Agency.
How old is 478TH AVE HWY 121 and does age affect safety?
478TH AVE HWY 121 was built in 2013, making it 13 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.