County profile · official public datasets

Pottawattamie County, IA

557 public highway bridges tracked in the FHWA National Bridge Inventory: 38.8% rated Good, 51.9% Fair, 9.3% Poor.

557
Public bridges: 38.8%
Good condition: 9.3%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Pottawattamie County posts a top-quartile lowest Poor-condition share among rated counties in the state across large county bridge inventory.

Top 17%
lowest Poor share in state: 9.3%
Poor-condition share: 557
public highway bridges: 1981
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Pottawattamie County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Pottawattamie County ranks #17 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.3%). Pottawattamie County, Iowa contains 557 public highway bridges. Roughly 38.8% are rated “Good,” 51.9% “Fair,” and 9.3% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

557

Public highway bridges in Pottawattamie County

Good condition

38.8%

216 of 557 rated 7-9

Fair condition

51.9%

289 of 557 rated 5-6

Poor condition

9.3%

52 of 557 rated 4 or below

In-state Poor-share rank

#17 of 99

Among Iowa counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 557 NBI-tracked bridges by lowest applicable component rating.

Good

38.8% (216)

Fair

51.9% (289)

Poor

9.3% (52)

Pottawattamie County's Poor-condition bridges carry 29,080 vehicle crossings a day

That is 1.6% of the county's reported daily bridge traffic on 9.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 559 crossings a day against 3,470 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 556 of 557 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

43.6% of Pottawattamie County's bridges have passed the 50-year mark

243 of the 557 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 38.8% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 25.7% of the county's Poor-condition bridge traffic

SOUTH EXPRESSWAY over VIADUCT(RR & STREETS), built 1976, carries 7,488 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 52-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 29,080 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

6
1930s

25
1940s

18
1950s

50
1960s

124
1970s

61
1980s

60
1990s

58
2000s

48
2010s

73
2020s

34

What this shows Construction peaked in the 1960s, when 124 of the county's bridges still in the inventory were built, which is 22.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1981) matches the Iowa average (1979).

How Pottawattamie County compares with Iowa's closest counties by inventory size

The 5 Iowa counties nearest Pottawattamie County in number of bridges, with their condition splits. Its 9.3% Poor share is the 5th-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1985 is in line with the group.

Showing the 5 closest of 98 Iowa counties eligible for comparison.

Bridge inventory size and condition shares for Pottawattamie County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Pottawattamie County (this page)	557	38.8%	51.9%	9.3%	1981
Polk County	545	57.8%	35.8%	6.4%	1986
Linn County	506	46.4%	47.2%	6.3%	1987
Black Hawk County	489	52.8%	40.7%	6.5%	1983
Woodbury County	455	39.3%	39.6%	21.1%	1985
Sioux County	449	62.4%	34.7%	2.9%	1982

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Pottawattamie County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Pottawattamie County, both outside Iowa so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IA (557 bridges here).

Yakima County, WA · 558 bridges
Larimer County, CO · 559 bridges
Chautauqua County, NY · 559 bridges
Buncombe County, NC · 555 bridges

Similar average build year

Nearest mean year-built outside IA (1981 here).

Franklin County, OH · avg 1981 · 922 bridges
Greenville County, SC · avg 1981 · 635 bridges
Montgomery County, OH · avg 1981 · 632 bridges
McLean County, IL · avg 1981 · 624 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 557 Good 216 Fair 289 Poor 52

All bridges (557)

Sort:

Pottawattamie County Bridge Snapshot

Condition distribution

Pottawattamie County's Poor-condition bridges carry 29,080 vehicle crossings a day

43.6% of Pottawattamie County's bridges have passed the 50-year mark

One structure carries 25.7% of the county's Poor-condition bridge traffic

How Pottawattamie County compares with Iowa's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (557)

EB I-80

435TH STREET

NB I-29

PIONEER TRAIL

FM-430TH STREET

FM

SUMAC ROAD

MAGNOLIA ROAD

US 59

EB I 80 & US 6

FM-LOMBARDY RD

WB I 80 & US 6

I 80 EB

WB I-80

460TH ST

YORK ROAD

410TH STREET

EASTERN HILLS D

SOUTH EXPRESSWAY

I 880 EB

FM-HONEYSUCKLE

ASPEN ROAD

2ND AVE

I 880 EB

WB I 80 & US 6

IA 906 WB

IA 92

US 59

I 880 EB

I 80

MCPHERSON AVE

432ND ST

400TH STREET

US 275 & IA 92

IA 906 EB

EB I 80 & US 6

I 880 WB

I 80 & US 6 WB

NB I-29

SB I-29

EB I-80

WB I-80

EB I-680

EB I 80 & US 6

380TH STREET

I-80 EB

FM-440TH STREET

FM-DOGWOOD RD

ROSEWOOD ROAD

JUNIPER ROAD

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