Yankton County Bridge Report Card
Yankton County scores 66 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Yankton County, South Dakota
Yankton County has 99 bridges in the National Bridge Inventory, with 13 rated poor and 2 rated scour-critical. Its poor-condition share of 13.1% is at or below the 16.1% statewide average. Poor-condition bridges carry about 5,715 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Yankton County a Bridge Condition Exposure Score of 66/100 (D). The county has 99 bridges in the National Bridge Inventory, including 13 in poor condition and 2 rated scour-critical. Poor-condition bridges carry about 5,715 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.
How the Score Breaks Down
| Factor | Weight | County Value | Penalty |
|---|---|---|---|
| Poor-condition bridge share | 40 | 13.1% | 26.3 |
| Poor-condition traffic exposure | 25 | 5.0% of measured traffic | 3.8 |
| Scour-critical bridge share | 20 | 2.0% | 4.0 |
| Average age vs national baseline | 10 | 41 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 113,394 measured daily crossings | 0.0 |
Score = 100 minus weighted penalties. The score is a comparative research signal, not an official safety rating. Read the full methodology.
County Comparisons
| County Poor-Condition Share | 13.1% |
| State Poor-Condition Share | 16.1% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 2.0% |
| Average Bridge Age | 41 years |
| Poor-Condition Traffic Exposure | 5,715 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Yankton County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| W 23rd Street over Marne Creek | Poor condition + traffic exposure | Poor | 3,980 | 1976 |
| Cedar Street over Marne Creek | Poor condition + traffic exposure | Poor | 969 | 1978 |
| 29280 431st Avenue over James River | Poor condition + traffic exposure | Poor | 315 | 1959 |
| 30430 446th Avenue over Unnamed Creek | Poor condition + traffic exposure | Poor | 100 | 1941 |
| 44960 296 ST over Turkey Creek | Poor condition + traffic exposure | Poor | 75 | 1979 |
| 44930 295 ST over Turkey Creek | Poor condition + traffic exposure | Poor | 75 | 1991 |
| 29250 442nd Avenue over Clay Creek | Poor condition + traffic exposure | Poor | 50 | 1930 |
| 45170 313 ST over Unnamed Creek | Poor condition + traffic exposure | Poor | 45 | 1940 |
| 30730 436th Avenue over Marne Creek | Poor condition + traffic exposure | Poor | 33 | 1935 |
| 29690 450 AVE over Turkey Creek | Poor condition + traffic exposure | Poor | 33 | 1987 |
Important safety note
Poor condition does not mean a bridge is unsafe. It means at least one major component has significant deterioration and the bridge is a priority for maintenance, repair, or replacement. Bridges judged unsafe are closed or restricted by transportation agencies.