Iowa bridge conditions
23,716 inventoried bridges · 4,423 rated poor · county by county
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 4,423 of Iowa's 23,716 inventoried bridges are rated in poor condition (18.6%) in the 2025 National Bridge Inventory, as of .
- 9,329 bridges (39.3%) are rated good and 9,964 (42.0%) fair.
- The national poor rate is about 6.7%; Iowa is above it (see all states ranked).
- The busiest poor-rated bridge in the state is US 67 over Miss Rvr RR & Ia 461 in Scott County, carrying about 26,500 vehicles a day.
By the measure that matters most - the most traffic on a poor rating - it is US 67 over Miss Rvr RR & Ia 461 in Scott County, built 1940, carrying about 26,500 vehicles a day. That is a repair-priority flag, not a collapse warning: what a poor rating does and does not mean. See the worst bridge in every state.
Good 39.3% · Fair 42.0% · Poor 18.6% of 23,716 bridges
Bridge conditions by county
Sorted by the number of poor-rated bridges. Click any county for its full bridge list.
The 25 busiest poor-rated bridges in Iowa
Frequently asked questions
How many bridges in Iowa are in poor condition?
4,423 of Iowa's 23,716 inventoried highway bridges are rated in poor condition (18.6%) in the 2025 National Bridge Inventory. 'Poor' is FHWA's classification for a bridge whose deck, superstructure, or substructure is rated 4 or lower on the 0-9 scale; it was formerly called 'structurally deficient'.
Are the poor-rated bridges in Iowa safe to drive on?
A poor rating flags advanced deterioration that needs repair or close monitoring; it does not by itself mean a bridge is unsafe. Bridges judged unsafe are closed or restricted to lighter loads by the owner. Inspections continue on all open bridges, generally at least every 24 months under the National Bridge Inspection Standards.
Source: FHWA National Bridge Inventory, 2025 vintage, reported by the Iowa DOT.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.