Grant County Bridge Report Card
Grant County scores 54 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Grant County, South Dakota
Grant County has 205 bridges in the National Bridge Inventory, with 38 rated poor and 5 rated scour-critical. Its poor-condition share of 18.5% is above the 16.1% statewide average. Poor-condition bridges carry about 4,821 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Grant County a Bridge Condition Exposure Score of 54/100 (F). The county has 205 bridges in the National Bridge Inventory, including 38 in poor condition and 5 rated scour-critical. Poor-condition bridges carry about 4,821 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 | 18.5% | 37.1 |
| Poor-condition traffic exposure | 25 | 5.9% of measured traffic | 4.4 |
| Scour-critical bridge share | 20 | 2.4% | 4.9 |
| Average age vs national baseline | 10 | 42 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 81,487 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 | 18.5% |
| State Poor-Condition Share | 16.1% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 2.4% |
| Average Bridge Age | 42 years |
| Poor-Condition Traffic Exposure | 4,821 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Grant County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| 482 Avenue over Whetstone Rv | Poor condition + traffic exposure | Poor | 57 | 1978 |
| 152 Street over Indian Rv | Poor condition + traffic exposure | Poor | 52 | 1932 |
| 2nd Avenue over Bnsf Railroad | Poor condition + traffic exposure | Poor | 2,560 | 1914 |
| W. Milbank St-milb over South Fork Whetstone Rv | Poor condition + traffic exposure | Poor | 696 | 1984 |
| 147 Street over Ck | Poor condition + traffic exposure | Poor | 100 | 1926 |
| 147 Street over Ck | Poor condition + traffic exposure | Poor | 100 | 1926 |
| 163 Street over South Fork Yellow Bank R | Poor condition + traffic exposure | Poor | 98 | 1930 |
| 480 Avenue over Ck | Poor condition + traffic exposure | Poor | 96 | 1969 |
| 475 Avenue over Ck | Poor condition + traffic exposure | Poor | 75 | 1965 |
| 466 Avenue over Ck | Poor condition + traffic exposure | Poor | 54 | 1930 |
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.