Lyman County Bridge Report Card

Lyman County scores 75 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

C75 / 100

Local infrastructure snapshot

Lyman County, South Dakota

Lyman County has 114 bridges in the National Bridge Inventory, with 12 rated poor and 1 rated scour-critical. Its poor-condition share of 10.5% is at or below the 16.1% statewide average. Poor-condition bridges carry about 3,490 daily vehicle crossings.

114Total Bridges

12Poor (10.5%)

56Fair (49.1%)

1Scour-Critical

Quote-Ready Local Facts

10.5%of county bridges are in poor condition, compared with 16.1% statewide and 6.7% nationally.

3,490daily vehicle crossings are on poor-condition bridges in the county.

1bridges are rated scour-critical, or 0.9% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Lyman County a Bridge Condition Exposure Score of 75/100 (C). The county has 114 bridges in the National Bridge Inventory, including 12 in poor condition and 1 rated scour-critical. Poor-condition bridges carry about 3,490 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	10.5%	21.1
Poor-condition traffic exposure	25	1.8% of measured traffic	1.4
Scour-critical bridge share	20	0.9%	1.8
Average age vs national baseline	10	49 years vs 48 nationally	0.6
Traffic-data completeness	5	190,955 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	10.5%
State Poor-Condition Share	16.1%
National Poor-Condition Share	6.7%
County Scour-Critical Share	0.9%
Average Bridge Age	49 years
Poor-Condition Traffic Exposure	3,490 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeI090 Wf over R&w Rr — 2,622 vehicles/day Oldest Listed Bridge2nd St. In Presho over Medicine Creek — built in 1920 All County BridgesBrowse every bridge record in Lyman County.

Top Bridges to Watch in Lyman County

Bridge	Reason	Condition	Daily Traffic	Year Built
I090 Wf over R&w Rr	Poor condition + traffic exposure	Poor	2,622	1953
IRR BIA RTE 5 over Counselor Creek	Poor condition + traffic exposure	Poor	663	1965
241st Street over Medicine Creek	Poor condition + traffic exposure	Poor	55	1930
241st Street over Trib. To Medicine Creek	Poor condition + traffic exposure	Poor	45	1930
318th Avenue over Creek	Poor condition + traffic exposure	Poor	24	1930
River Road over Creek	Poor condition + traffic exposure	Poor	16	1965
338th Avenue over Waterhole Creek	Poor condition + traffic exposure	Poor	15	1950
327th Avenue over Creek	Poor condition + traffic exposure	Poor	10	1940
County RD over Ck	Poor condition + traffic exposure	Poor	10	1945
County RD over Ck	Poor condition + traffic exposure	Poor	10	1950

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.