Monona County Bridge Report Card
Monona County scores 49 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Monona County, Iowa
Monona County has 160 bridges in the National Bridge Inventory, with 41 rated poor and 0 rated scour-critical. Its poor-condition share of 25.6% is above the 18.6% statewide average. Poor-condition bridges carry about 12,459 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Monona County a Bridge Condition Exposure Score of 49/100 (F). The county has 160 bridges in the National Bridge Inventory, including 41 in poor condition and 0 rated scour-critical. Poor-condition bridges carry about 12,459 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 | 25.6% | 40.0 |
| Poor-condition traffic exposure | 25 | 12.9% of measured traffic | 9.7 |
| Scour-critical bridge share | 20 | 0.0% | 0.0 |
| Average age vs national baseline | 10 | 51 years vs 48 nationally | 1.1 |
| Traffic-data completeness | 5 | 96,276 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 | 0.0% |
| Average Bridge Age | 51 years |
| Poor-Condition Traffic Exposure | 12,459 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Monona County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| Ia 175 over I-29 | Poor condition + traffic exposure | Poor | 4,090 | 1959 |
| Ia 141 & 175 over Maple River | Poor condition + traffic exposure | Poor | 3,720 | 1967 |
| FM over Dd | Poor condition + traffic exposure | Poor | 597 | 1959 |
| FM over Diversion Ditch | Poor condition + traffic exposure | Poor | 597 | 1962 |
| FM over Famers Garretson Ditch | Poor condition + traffic exposure | Poor | 578 | 1962 |
| FM over Soldier River | Poor condition + traffic exposure | Poor | 349 | 1955 |
| FM over Haitz Dd | Poor condition + traffic exposure | Poor | 229 | 1961 |
| FM over West Fork Dd | Poor condition + traffic exposure | Poor | 229 | 1961 |
| FM over Willow Creek | Poor condition + traffic exposure | Poor | 199 | 1979 |
| FM over Little Sioux River | Poor condition + traffic exposure | Poor | 159 | 1925 |
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.