Lake County Bridge Report Card
Lake County scores 86 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Lake County, South Dakota
Lake County has 79 bridges in the National Bridge Inventory, with 4 rated poor and 1 rated scour-critical. Its poor-condition share of 5.1% is at or below the 16.1% statewide average. Poor-condition bridges carry about 940 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Lake County a Bridge Condition Exposure Score of 86/100 (B). The county has 79 bridges in the National Bridge Inventory, including 4 in poor condition and 1 rated scour-critical. Poor-condition bridges carry about 940 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 | 5.1% | 10.1 |
| Poor-condition traffic exposure | 25 | 1.6% of measured traffic | 1.2 |
| Scour-critical bridge share | 20 | 1.3% | 2.5 |
| Average age vs national baseline | 10 | 48 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 58,569 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 | 5.1% |
| State Poor-Condition Share | 16.1% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 1.3% |
| Average Bridge Age | 48 years |
| Poor-Condition Traffic Exposure | 940 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Lake County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| 461 AVE over Ck | Poor condition + traffic exposure | Poor | 580 | 1950 |
| 449 AVE over Ck | Poor condition + traffic exposure | Poor | 290 | 1930 |
| 231 ST over East Fork Vermillion Rv | Poor condition + traffic exposure | Poor | 55 | 1930 |
| 464 AVE over Battle Ck | Poor condition + traffic exposure | Poor | 15 | 1930 |
| 235 ST over Park Ck | Scour-critical foundation rating | Fair | 684 | 1937 |
| Sd034 over Silver Ck | High traffic | Fair | 8,695 | 2000 |
| 414 NE Second Str over Madison Ck | High traffic | Fair | 7,576 | 1959 |
| Sd034 W over Park Ck | High traffic | Fair | 3,631 | 1977 |
| Sd034 E over Park Ck | High traffic | Fair | 3,631 | 1977 |
| 500 N Egan AVE over Madison Ck | High traffic | Fair | 3,190 | 1993 |
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.