Scale of the Problem
Iowa has 23,716 bridges. (ARTBA 2025) Of those, 4,424 are rated in poor condition, which is 19% of the state's inventory. That is the highest rate of any state in the country. (ARTBA 2025)
The national average is 6.7%. (ARTBA 2025) Iowa's rate is nearly three times that. West Virginia ranks second at 18%, but with far fewer total bridges (7,345 vs. Iowa's 23,716). In raw numbers, only Pennsylvania has more poor bridges (2,813), and Pennsylvania's rate is 12%. Iowa combines a massive inventory with a high deficiency rate in a way no other state matches.
Iowa also has the 7th-largest bridge inventory in the nation, so the 19% rate is applied to a large base. The result is over 4,400 structures that need repair or replacement. The full state breakdown is available on ARTBA's Iowa bridge profile.
The Ownership Split
This is the single most important thing to understand about Iowa's bridge situation. The Iowa DOT owns roughly 4,200 bridges. Counties own approximately 18,225. Cities own about 1,250. Local agencies collectively control over 80% of the state's bridge inventory. (Iowa DOT 2024)
The condition gap between state-owned and locally-owned bridges is where the story becomes clear. As of 2024, the DOT has 23 bridges rated poor. Counties have over 4,300. There are more poor county bridges than there are total DOT-owned bridges. (Iowa DOT 2024; The Gazette)
All but roughly 23 of Iowa's 4,424 poor bridges are locally owned. The poor bridge problem in Iowa is almost entirely a county and city problem, not a state highway problem. (ASCE Iowa Report Card)
Local Public Agency poor bridges make up 23% of the LPA bridge inventory and 18% of total LPA deck area. (Iowa DOT 2024) Counties carry a disproportionate burden because Iowa's extensive secondary road system was built to move farm products to market, and that grid requires thousands of creek and stream crossings.
The Two-Speed Trend
In 2009, the Iowa DOT had 237 bridges rated poor. By 2024, that number was 23. That is roughly a 90% reduction over 15 years. (Iowa DOT 2024; The Gazette) The DOT credits a deliberate stewardship strategy focused on preservation and timely rehabilitation.
County progress looks different. Over a recent four-year period, counties reduced their poor bridge count by approximately 4%. Cities managed about 5%. (ASCE Iowa Report Card) Statewide, the net reduction was roughly 80 bridges over three years, from approximately 4,500 to 4,424. (ARTBA data)
| Owner | Poor Bridges (Start) | Poor Bridges (2024) | Change |
|---|---|---|---|
| Iowa DOT | 237 (2009) | 23 | -90% |
| Counties | ~4,490 (2020) | ~4,306 | -4% |
| Cities | ~265 (2020) | ~252 | -5% |
A TRIP report from September 2024 found that 21% of Iowa's rural bridges are rated poor or structurally deficient, the highest rate among all states and well above the nationwide rural average of 8%. (TRIP Sept 2024)
At the current rate of county-level improvement, the statewide backlog barely moves. Iowa's #1 ranking is unlikely to change without a step-change in local funding or capacity.
Why Iowa Has So Many Bridges
Iowa is almost entirely agricultural. Thousands of creeks, streams, and drainage ditches cross a dense county road grid that was built to move grain, livestock, and equipment from farms to market. Every waterway crossing on every secondary road requires a bridge or culvert, and Iowa has 99 counties maintaining these networks.
The Mississippi River forms the state's entire eastern border. The Missouri River runs along most of the western border. Interior rivers including the Des Moines, Cedar, and Iowa add major crossings throughout the state. The combination of a flat agricultural landscape, dense surface drainage, and a thorough rural road grid explains why Iowa has the 7th-largest bridge inventory in the nation.
Bridge age compounds the problem. The average age of all Iowa highway bridges is 41 years. For locally-owned bridges, the average is 46 years. (Iowa DOT 2024) Most county bridges are short-span structures over small waterways, built decades ago to standards that did not anticipate modern agricultural equipment weights. Iowa DOT maintains an interactive bridge conditions map showing every structure in the inventory.
What Poor Bridges Mean for Agriculture and Safety
Iowa is the nation's top producer of corn and hogs and a leading soybean producer. The rural bridge network is the backbone of the farm-to-market supply chain. Grain trucks, livestock haulers, and agricultural equipment depend on secondary road bridges that are disproportionately in poor condition.
Of Iowa's poor-rated bridges, 68% are weight-posted or otherwise restricted. (Iowa DOT 2024) Another 331 bridges are closed to traffic entirely. (Iowa DOT 2023) Weight restrictions force detours for heavy vehicles including farm equipment, commercial trucks, school buses, and emergency apparatus. Half of poor bridges on county roads carry fewer than 35 vehicles per day (Iowa DOT 2024), but those vehicles frequently include loaded grain trucks and full-size farm implements.
The worst-affected counties illustrate how concentrated the problem is.
| County | % Poor | Location |
|---|---|---|
| Ringgold | ~44% | South-central, Missouri border |
| Adams | ~43% | Southwest, Missouri border |
| Poweshiek | ~42% | Central Iowa |
(FHWA NBI analysis)
In these counties, nearly every other bridge a driver crosses is rated poor. Emergency access is a real concern. Fire trucks and ambulances are among the heaviest vehicles affected by weight postings, and rural response times already stretch thin across Iowa's low-density southern counties.
Washington County's $38.64 million federal grant for seven bridge replacements was explicitly branded "Building Bridges Today Helping Feed America Tomorrow," a direct acknowledgment that Iowa's bridge infrastructure and its agricultural economy are inseparable. (US DOT)
Funding and What's Been Done
Iowa raised its fuel tax by 10 cents per gallon in 2015, a bipartisan vote signed by Republican Governor Terry Branstad. Iowa was the first state to pass a fuel tax increase that year. The current gasoline tax is 30 cents per gallon. (Transportation for America)
Over its first three years, the increase generated $515 million: $245 million to state roads, $167 million to county roads, and $103 million to cities. (Globe Gazette) That revenue helped fund bridge work at every level, but the scale of the county backlog means the additional money has not been enough to reverse the trend.
Under the federal Infrastructure Investment and Jobs Act, Iowa's Bridge Formula Program allocation is $467.1 million over five years. As of mid-2025, $150.2 million has been committed across 197 projects. (ARTBA) The state also runs a Federal-aid Swap Program that lets local agencies trade federal dollars for state funds, reducing the administrative burden that can slow small-county projects.
The ASCE gave Iowa bridges a grade of D+ in its most recent state infrastructure report card, compared to a national bridge grade of C. (ASCE 2023; ASCE 2025) Federal earmarks have proven fragile: Burlington's Cascade Bridge lost $6 million in Community Project Funding when House Republicans cancelled earmarks in March 2025. (Iowa Public Radio)
Bridges to Watch
Black Hawk Bridge, Lansing
The Black Hawk Bridge carried Iowa Highway 9 and Wisconsin Highway 82 over the Mississippi River between Lansing and Crawford County, Wisconsin. A replacement bridge has been under construction since late 2023. The existing structure was temporarily closed twice for structural concerns: once in early 2024 after observed displacement in a support pier, and again for three weeks in summer 2025 after sensors detected movement. (Iowa DOT; WPR)
Governor Kim Reynolds issued a disaster proclamation for Allamakee and Clayton counties on February 29, 2024, activating FHWA emergency funds. (Governor's Office) The old bridge was demolished by implosion on December 19, 2025. The replacement is scheduled to open in 2027. (Iowa DOT)
Cascade Bridge, Burlington
The Cascade Bridge is a 129-year-old Baltimore truss bridge listed on the National Register of Historic Places. It has been closed to vehicle traffic since 2008 and to pedestrians since 2019. Representative Miller-Meeks secured $6 million in federal Community Project Funding for its reopening, but that earmark was cancelled in March 2025. (Iowa Public Radio)
A separate $10.5 million replacement project remains in the pipeline, partially funded by a $1 million Iowa DOT grant and $1 million from the National Scenic Byways Program. (KWQC; OurQuadCities) The Cascade Bridge illustrates a pattern common in Iowa: a small city's historic structure stuck in funding limbo while the state prioritizes its own high-traffic crossings.
What "Poor Condition" Means
A bridge is classified as being in "poor condition" if any one of its three primary components (deck, superstructure, or substructure) receives a rating of 4 or below on the NBI's 0-to-9 scale. A poor rating does not mean a bridge is unsafe or at risk of collapse. It means the bridge has deteriorated to the point where it needs repair or replacement. Bridges rated poor are typically subject to increased inspection frequency, load restrictions, or both.
Data Sources
Statewide totals (23,716 bridges, 4,424 poor, 19%, rank #1) are from the ARTBA 2025 Bridge Report, which is based on 2025 FHWA National Bridge Inventory data. Ownership breakdowns and condition trends are from the Iowa DOT 2023 and 2024 Annual Bridge Reports. County-level percentages are from FHWA NBI analysis. Funding data is from ARTBA, the Iowa DOT, and federal sources as cited inline.
Caveats
Bridge inspection practices and rating standards can vary by inspector and agency. The NBI captures a snapshot in time; individual bridge conditions change between inspection cycles. County-level poor percentages cited in this article use data analyzed by third parties (FHWA NBI datasets) and may reflect slightly different reporting periods than the statewide ARTBA totals.