Lyon County Bridge Report Card

Lyon County scores 35 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

F35 / 100

Local infrastructure snapshot

Lyon County, Iowa

Lyon County has 273 bridges in the National Bridge Inventory, with 70 rated poor and 17 rated scour-critical. Its poor-condition share of 25.6% is above the 18.6% statewide average. Poor-condition bridges carry about 15,361 daily vehicle crossings.

273Total Bridges

70Poor (25.6%)

99Fair (36.3%)

17Scour-Critical

Quote-Ready Local Facts

25.6%of county bridges are in poor condition, compared with 18.6% statewide and 6.7% nationally.

15,361daily vehicle crossings are on poor-condition bridges in the county.

17bridges are rated scour-critical, or 6.2% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Lyon County a Bridge Condition Exposure Score of 35/100 (F). The county has 273 bridges in the National Bridge Inventory, including 70 in poor condition and 17 rated scour-critical. Poor-condition bridges carry about 15,361 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	25.6%	40.0
Poor-condition traffic exposure	25	14.5% of measured traffic	10.9
Scour-critical bridge share	20	6.2%	12.5
Average age vs national baseline	10	51 years vs 48 nationally	1.3
Traffic-data completeness	5	105,812 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	25.6%
State Poor-Condition Share	18.6%
National Poor-Condition Share	6.7%
County Scour-Critical Share	6.2%
Average Bridge Age	51 years
Poor-Condition Traffic Exposure	15,361 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeA26 (180th St) over Big Sioux River — 1,017 vehicles/day Oldest Listed BridgeLog AVE over West Rat Creek — built in 1900 All County BridgesBrowse every bridge record in Lyon County.

Top Bridges to Watch in Lyon County

Bridge	Reason	Condition	Daily Traffic	Year Built
FM over Little Rock River	Poor condition + traffic exposure	Poor	709	1954
FM over Mud Creek	Poor condition + traffic exposure	Poor	509	1961
FM over Klondike Creek	Poor condition + traffic exposure	Poor	309	1966
Local Road over Small Stream	Poor condition + traffic exposure	Poor	62	1900
Local Road over Pinney Creek	Poor condition + traffic exposure	Poor	62	1900
Local Road over Hefferman Creek	Poor condition + traffic exposure	Poor	46	1900
Local Road over Klondike Creek	Poor condition + traffic exposure	Poor	41	1900
Local Road over Emery Creek	Poor condition + traffic exposure	Poor	35	1900
Local Road over Over Flow	Poor condition + traffic exposure	Poor	30	1900
Local Road over Overflow	Poor condition + traffic exposure	Poor	26	1900

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.