Plymouth County Bridge Report Card

Plymouth County scores 55 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

F55 / 100

Local infrastructure snapshot

Plymouth County, Iowa

Plymouth County has 430 bridges in the National Bridge Inventory, with 90 rated poor and 4 rated scour-critical. Its poor-condition share of 20.9% is above the 18.6% statewide average. Poor-condition bridges carry about 17,647 daily vehicle crossings.

430Total Bridges

90Poor (20.9%)

107Fair (24.9%)

4Scour-Critical

Quote-Ready Local Facts

20.9%of county bridges are in poor condition, compared with 18.6% statewide and 6.7% nationally.

17,647daily vehicle crossings are on poor-condition bridges in the county.

4bridges are rated scour-critical, or 0.9% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Plymouth County a Bridge Condition Exposure Score of 55/100 (F). The county has 430 bridges in the National Bridge Inventory, including 90 in poor condition and 4 rated scour-critical. Poor-condition bridges carry about 17,647 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	20.9%	40.0
Poor-condition traffic exposure	25	3.7% of measured traffic	2.8
Scour-critical bridge share	20	0.9%	1.9
Average age vs national baseline	10	50 years vs 48 nationally	0.7
Traffic-data completeness	5	479,721 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	20.9%
State Poor-Condition Share	18.6%
National Poor-Condition Share	6.7%
County Scour-Critical Share	0.9%
Average Bridge Age	50 years
Poor-Condition Traffic Exposure	17,647 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeUS 75 over Stream — 14,000 vehicles/day Oldest Listed BridgeRoosevelt AVE over W F Little Sioux — built in 1900 All County BridgesBrowse every bridge record in Plymouth County.

Top Bridges to Watch in Plymouth County

Bridge	Reason	Condition	Daily Traffic	Year Built
170th ST over Drainage	Poor condition + traffic exposure	Poor	34	1900
Impala AVE over Mink Creek	Poor condition + traffic exposure	Poor	26	1938
190th ST over Mink Creek	Poor condition + traffic exposure	Poor	15	1947
200th ST over Clear Creek	Poor condition + traffic exposure	Poor	5	1946
US 75 over Stream	Poor condition + traffic exposure	Poor	14,000	1926
FM over Stephens Creek	Poor condition + traffic exposure	Poor	628	1960
FM K-42 over Carter Creek	Poor condition + traffic exposure	Poor	190	1941
FM K-42 over Carter Creek	Poor condition + traffic exposure	Poor	190	1966
FM C-43 over Broken Kettle Creek	Poor condition + traffic exposure	Poor	159	1960
150th ST over Floyd River	Poor condition + traffic exposure	Poor	131	1954

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.