30999 477TH AVE
Carrying 30999 477TH AVE over CK
9S & 2W ALCESTER, Union, South Dakota
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: 30999 477TH AVE
The 30999 477TH AVE bridge in Union, South Dakota carries 30999 477TH AVE over CK. It was built in 1989, making it 37 years old today. The structure is built primarily of concrete and spans 1 section, stretching 7.8 meters (26 feet) end to end. Daily traffic averages 300 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 4/9, superstructure at 3/9, substructure at 3/9. 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 12.2 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How 30999 477TH AVE 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 How the historical reference is calculated.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
- 1989
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 7.8 m (26 ft)
- Deck Width
- 8.8 m (29 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 300 vehicles/day
- Structure Number
- 000000064070130
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in poor condition (4/9), showing advanced deterioration that may require priority repair.
- • At 3/9, the superstructure (beams and supports above the deck) is in poor shape, with advanced wear flagged for priority repair.
- • At 3/9, the substructure (piers and abutments) is in poor shape, with advanced wear flagged for priority repair.
How to read this record
30999 477TH AVE 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 30999 477TH AVE against other structures in Union 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 30999 477TH AVE?
30999 477TH AVE in Union, South Dakota has a deck rating of 4/9, superstructure rating of 3/9, and substructure rating of 3/9 on the FHWA's 0–9 scale.
How often is 30999 477TH AVE inspected?
30999 477TH AVE'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 300 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 30999 477TH AVE 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 30999 477TH AVE?
30999 477TH AVE has an NBI inventory load rating of 12.2 metric tons.
Who is responsible for maintaining 30999 477TH AVE?
30999 477TH AVE is owned and maintained by County Highway Agency.
How old is 30999 477TH AVE and does age affect safety?
30999 477TH AVE was built in 1989, making it 37 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.