vlog Investigates: Iowa ranks 7th in US with its number of bridges
Iowa consistently ranks first as having the highest number of bridges in poor condition. In fact, a recent report from the American Civil Engineers Society confirmed this ranking again.
There's a key reason for that, according to Jim Nelson, the director of the Bridges and Structures bureau of the Iowa Department of Transportation.
"One of the driving factors of that is we have an aging inventory," Nelson said.
Most of Iowa's nearly 24,000 bridges were built in the 1950s, 60s, 70s and 80s.
Some are even older.
The Black Hawk Bridge in Lansing, Iowa, was built in 1931. It links Iowa to Wisconsin and is currently being replaced.
This kind of project is expensive. The Lansing bridge will cost $140 million. Federal funds will cover 80 percent, with Iowa and Wisconsin splitting the rest of the tab.
Bridges have a 50- to 75-year lifespan. Most of those in Iowa are reaching the end of their use.
"We have a tremendous amount of bridges on low-volume roads that are classified as poor," Nelson said.
vlog visited a rarely used bridge this week, the Harvey Railroad bridge in rural Marion County. It was first built as a railroad bridge in 1878. It gets an average of 12 cars a day going across its one lane, according to the National Bridge Inventory.
vlog Investigates and the Hearst National Investigative team looked at the number of Iowa bridges in poor, fair or good shape in the last 20 years using data from the National Bridge Inventory.
"For bridges overall, we're seventh among the country. Texas is by far first. They have almost twice as many bridges as we do," Nelson said.
After Texas, Illinois comes in second for the number of bridges.
States with the most bridges, according to National Bridge Inventory numbers.
- Texas: 56,729
- Illinois: 26,928
- Ohio: 26,729
- California: 25,848
- Kansas: 24,894
- Missouri: 24,618
The national inventory shows Iowa with almost 24,000 bridges in 2024. About 23% of them were in poor condition; 42% in fair and 35% in good.
In 2005, the percentages were similar — 2005: 21% in poor, 42% in fair, 37% in good. Iowa had more than 21,000 bridges then.
As bridges are replaced or repaired, others may go from good to fair condition or fair to poor condition. A reminder: Experts say a poor bridge is still safe; it's in need of repair.
The maintenance goes in cycles, said Iowa County Engineers Association Service Bureau director Brian Moore.
"We can expect more of those to start to decay," Moore said. "It just goes in waves over time as you replace that wave."
In any given construction season, Nelson said, there are more than 100 projects underway. There are usually 30 to 40 bridge replacements, and capacity improvements and bridge overlays.
With roads and bridges in Iowa needed for heavy farming vehicles and machines, the upkeep is necessary.
"There's always going to be work, there's always going to be work," said Moore.