County profile · official public datasets

Ida County, IA

182 public highway bridges tracked in the FHWA National Bridge Inventory: 42.9% rated Good, 40.7% Fair, 16.5% Poor.

182
Public bridges: 42.9%
Good condition: 16.5%
Poor condition

The verdict

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

Ida County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 39%
lowest Poor share in state: 16.5%
Poor-condition share: 182
public highway bridges: 1983
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.

Ida County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Ida County ranks #39 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 16.5%). Ida County, Iowa contains 182 public highway bridges. Roughly 42.9% are rated “Good,” 40.7% “Fair,” and 16.5% “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

182

Public highway bridges in Ida County

Good condition

42.9%

78 of 182 rated 7-9

Fair condition

40.7%

74 of 182 rated 5-6

Poor condition

16.5%

30 of 182 rated 4 or below

In-state Poor-share rank

#39 of 99

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

Condition distribution

Share of 182 NBI-tracked bridges by lowest applicable component rating.

Good

42.9% (78)

Fair

40.7% (74)

Poor

16.5% (30)

Ida County's Poor-condition bridges carry 10,957 vehicle crossings a day

That is 12.8% of the county's reported daily bridge traffic on 16.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 365 crossings a day against 527 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 182 of 182 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38.5% of Ida County's bridges have passed the 50-year mark

70 of the 182 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 42.9% 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 26.3% of the county's Poor-condition bridge traffic

LOCAL over ODEBOLT CREEK, built 1967, carries 2,884 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 30-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 10,957 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

9
1930s

4
1940s

3
1950s

8
1960s

29
1970s

21
1980s

20
1990s

32
2000s

31
2010s

18
2020s

7

What this shows Construction peaked in the 1990s, when 32 of the county's bridges still in the inventory were built, which is 17.6% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).

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

The 5 Iowa counties nearest Ida County in number of bridges, with their condition splits. Its 16.5% Poor share is the 2nd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1976 is 7 years newer.

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

Bridge inventory size and condition shares for Ida County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Osceola County	185	38.4%	53%	8.6%	1965
Mills County	184	29.3%	51.6%	19%	1976
Appanoose County	183	41%	27.9%	31.1%	1981
Keokuk County	183	34.4%	45.9%	19.7%	1980
Wright County	182	35.2%	35.7%	29.1%	1979
Ida County (this page)	182	42.9%	40.7%	16.5%	1983

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 Ida 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 Ida County, both outside Iowa so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IA (182 bridges here).

Logan County, CO · 182 bridges
Pulaski County, KY · 182 bridges
Jackson County, MN · 182 bridges
Scott County, MO · 182 bridges

Similar average build year

Nearest mean year-built outside IA (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Will County, IL · avg 1983 · 649 bridges

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

All 182 Good 78 Fair 74 Poor 30

All bridges (182)

Sort:

Ida County Bridge Snapshot

Condition distribution

Ida County's Poor-condition bridges carry 10,957 vehicle crossings a day

38.5% of Ida County's bridges have passed the 50-year mark

One structure carries 26.3% of the county's Poor-condition bridge traffic

How Ida 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 (182)

FM

FM

LOCAL

LOCAL

LOCAL ROAD

LOCAL

US 59

FM

FM

FM

FM

FM

LOCAL

LOCAL

FM

FM

LOCAL

LOCAL ROAD

FM

LOCAL

LOCAL

FM

L51 BRADY AVE

FM

L67 EAGLE AVE

FM

LOCAL

IA 175

FM

IA 175

FM

LOCAL

LOCAL

LOCAL

KEYSTONE

FM

FM

FM

US 59

US 59

IA 175

US 20 EB

LOCAL

LOCAL ROAD

FM

FM

LOCAL

FM

FM

FM

Related