Gregory County Bridge Report Card

Gregory County scores 73 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

C73 / 100

Local infrastructure snapshot

Gregory County, South Dakota

Gregory County has 51 bridges in the National Bridge Inventory, with 5 rated poor and 1 rated scour-critical. Its poor-condition share of 9.8% is at or below the 16.1% statewide average. Poor-condition bridges carry about 321 daily vehicle crossings.

51Total Bridges

5Poor (9.8%)

31Fair (60.8%)

1Scour-Critical

Quote-Ready Local Facts

9.8%of county bridges are in poor condition, compared with 16.1% statewide and 6.7% nationally.

321daily vehicle crossings are on poor-condition bridges in the county.

1bridges are rated scour-critical, or 2.0% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Gregory County a Bridge Condition Exposure Score of 73/100 (C). The county has 51 bridges in the National Bridge Inventory, including 5 in poor condition and 1 rated scour-critical. Poor-condition bridges carry about 321 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.

Download all county report-card scores as CSV.

How the Score Breaks Down

Factor	Weight	County Value	Penalty
Poor-condition bridge share	40	9.8%	19.6
Poor-condition traffic exposure	25	4.1% of measured traffic	3.1
Scour-critical bridge share	20	2.0%	3.9
Average age vs national baseline	10	49 years vs 48 nationally	0.6
Traffic-data completeness	5	7,891 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	9.8%
State Poor-Condition Share	16.1%
National Poor-Condition Share	6.7%
County Scour-Critical Share	2.0%
Average Bridge Age	49 years
Poor-Condition Traffic Exposure	321 vehicles/day

Bridges to Watch

Busiest Poor-Condition Bridge354 Avenue over Ponca Ck — 189 vehicles/day Oldest Listed Bridge297 Street over Ck — built in 1920 All County BridgesBrowse every bridge record in Gregory County.

Top Bridges to Watch in Gregory County

Bridge	Reason	Condition	Daily Traffic	Year Built
354 Avenue over Ponca Ck	Poor condition + traffic exposure	Poor	189	1952
State Park RD over South Scalp Ck	Poor condition + traffic exposure	Poor	50	1963
352 Avenue over Willow Ck	Poor condition + traffic exposure	Poor	36	1956
366 Avenue over North Scalp Ck	Poor condition + traffic exposure	Poor	36	2015
297 Street over Ck	Poor condition + traffic exposure	Poor	10	1920
345 Avenue over South Fork Whetstone Ck	High traffic	Good	560	2001
Sd047 over Ck	High traffic	Fair	552	1957
Sd047 over Ck	High traffic	Fair	552	1957
Sd044 over Bull Ck	High traffic	Good	540	1971
Sd044 over Lone Tree Ck	High traffic	Fair	540	1971

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.