County profile · official public datasets

Warren County, IA

239 public highway bridges tracked in the FHWA National Bridge Inventory: 42.7% rated Good, 36.8% Fair, 20.5% Poor.

239
Public bridges: 42.7%
Good condition: 20.5%
Poor condition

The verdict

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

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

56th
of 99 on Poor share: 20.5%
Poor-condition share: 239
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.

Warren County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Warren County ranks #56 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 20.5%). Warren County, Iowa contains 239 public highway bridges. Roughly 42.7% are rated “Good,” 36.8% “Fair,” and 20.5% “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

239

Public highway bridges in Warren County

Good condition

42.7%

102 of 239 rated 7-9

Fair condition

36.8%

88 of 239 rated 5-6

Poor condition

20.5%

49 of 239 rated 4 or below

In-state Poor-share rank

#56 of 99

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

Condition distribution

Share of 239 NBI-tracked bridges by lowest applicable component rating.

Good

42.7% (102)

Fair

36.8% (88)

Poor

20.5% (49)

Warren County's Poor-condition bridges carry 8,666 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 20.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 177 crossings a day against 2,840 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 239 of 239 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

41% of Warren County's bridges have passed the 50-year mark

98 of the 239 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 42.7% 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 19.8% of the county's Poor-condition bridge traffic

FM over NORTH RIVER, built 1960, carries 1,714 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 49-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 8,666 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1910s

1
1920s

4
1940s

17
1950s

30
1960s

23
1970s

34
1980s

29
1990s

24
2000s

25
2010s

43
2020s

8

What this shows Construction peaked in the 2010s, when 43 of the county's bridges still in the inventory were built, which is 18% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).

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

The 5 Iowa counties nearest Warren County in number of bridges, with their condition splits. Its 20.5% Poor share is the 4th-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1979 is in line with the group.

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

Bridge inventory size and condition shares for Warren County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Cherokee County	248	34.3%	36.7%	29%	1968
Jackson County	246	26.4%	56.5%	17.1%	1983
Hardin County	241	36.1%	36.1%	27.8%	1981
Iowa County	241	37.3%	43.6%	19.1%	1980
Warren County (this page)	239	42.7%	36.8%	20.5%	1983
Jones County	231	36.8%	58.9%	4.3%	1981

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

Similar inventory size

Nearest county inventories outside IA (239 bridges here).

Greene County, IN · 239 bridges
Wood County, WI · 239 bridges
Jefferson Davis County, LA · 240 bridges
St. Louis city County, MO · 240 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 239 Good 102 Fair 88 Poor 49

All bridges (239)

Sort:

Warren County Bridge Snapshot

Condition distribution

Warren County's Poor-condition bridges carry 8,666 vehicle crossings a day

41% of Warren County's bridges have passed the 50-year mark

One structure carries 19.8% of the county's Poor-condition bridge traffic

How Warren 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 (239)

G 76

NB I-35

SB I-35

I 35 NB

I 35 SB

G6R HOOVER ST

I 35 NB

I 35 SB

FILLMORE ST

I 35 NB

I 35 SB

G 14

R35 ADAMS ST

190TH

G76

R73 138TH AVE

R45

R45

MCKINLEY ST

210TH AVE

220TH AVE

30TH AVE

180TH AVE

168TH AVE

R63 98TH AVE

R 57

HOOVER ST

KIRKWOOD ST

168TH AVE

CLOVER HILL DR

115TH AVE

R35 10TH AVE

DUBUQUE PLACE

COUNTY LINE ROAD

VETERANS PARKWAY

I-35

150TH

FM

80TH AVE

FM

LOCAL ROAD

LOCAL

FM

LOCAL

FM

LOCAL

230TH AVE

IA 5 SB

FLEUR DR

COUNTY LINE RD

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