County profile · official public datasets

Cass County, IA

295 public highway bridges tracked in the FHWA National Bridge Inventory: 25.4% rated Good, 41% Fair, 33.6% Poor.

295
Public bridges
25.4%
Good condition
33.6%
Poor condition

The verdict

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

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

90th
of 99 on Poor share
33.6%
Poor-condition share
295
public highway bridges
1976
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.

Cass County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Cass County ranks #90 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 33.6%). Cass County, Iowa contains 295 public highway bridges. Roughly 25.4% are rated “Good,” 41% “Fair,” and 33.6% “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

295

Public highway bridges in Cass County

Good condition

25.4%

75 of 295 rated 7-9

Fair condition

41%

121 of 295 rated 5-6

Poor condition

33.6%

99 of 295 rated 4 or below

In-state Poor-share rank

#90 of 99

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

Condition distribution

Share of 295 NBI-tracked bridges by lowest applicable component rating.

Good
25.4% (75)
Fair
41% (121)
Poor
33.6% (99)

Cass County's Poor-condition bridges carry 7,249 vehicle crossings a day

That is 2% of the county's reported daily bridge traffic on 33.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 73 crossings a day against 2,130 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 293 of 295 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

40.7% of Cass County's bridges have passed the 50-year mark

120 of the 295 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 25.4% 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 21% of the county's Poor-condition bridge traffic

FM - OLIVE over NISHNABOTNA RIVER, built 1961, carries 1,524 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 99-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 7,249 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Cass County's bridges were built

295 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 60 of the county's bridges still in the inventory were built, which is 20.3% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1976) matches the Iowa average (1979).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 Iowa counties nearest Cass County in number of bridges, with their condition splits. Its 33.6% Poor share is the 6th-lowest of these 6. Its average build year of 1976 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 Cass County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Cedar County 301 19.6%
Crawford County 301 9%
Story County 296 13.9%
Cass County (this page) 295 33.6%
Delaware County 293 6.8%
Scott County 291 10.3%

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

Similar inventory size

Nearest county inventories outside IA (295 bridges here).

Similar average build year

Nearest mean year-built outside IA (1976 here).

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

All 295 Good 75 Fair 121 Poor 99

Good-condition bridges (75)

LOCAL - 665TH

Good

Over: TURKEY CREEK

076350712, Cass, IA

Built 1991 Load: 37.7 t ADT: 62

LOCAL - JASPER

Good

Over: TURKEY CREEK

076362203, Cass, IA

Built 1988 Load: 37.7 t ADT: 91

IA 148

Good

Over: TURKEY CREEK

0.2 MI. S OF IA 83, Cass, IA

Built 1995 Load: 38.3 t ADT: 2,010

EB I-80

Good

Over: EAST NISHNABOTNA RIVER

0.6 mi. E of Jct. U.S. 71, Cass, IA

Built 2009 Load: 38.8 t ADT: 11,550

LOCAL - NSHNA V

Good

Over: NISHNABOTNA RIVER

075371003, Cass, IA

Built 1992 Load: 39.5 t ADT: 82

FM - LANSING

Good

Over: WATERWAY

076363101, Cass, IA

Built 1997 Load: 40.1 t ADT: 34

WB I-80

Good

Over: TROUBLESOME CREEK

4.5 MI. E OF US 71, Cass, IA

Built 2003 Load: 40.5 t ADT: 11,500

US 6 & 71

Good

Over: TROUBLESOME CREEK

1.0 MI. N OF E JCT. IA 83, Cass, IA

Built 1993 Load: 40.6 t ADT: 2,230

IA 92

Good

Over: WEST NODAWAY RIVER

1.9 mi. E of Jct. IA 148, Cass, IA

Built 2010 Load: 41.2 t ADT: 920

EB I-80

Good

Over: TROUBLESOME CREEK

4.5 MI. E OF US 71, Cass, IA

Built 2003 Load: 42.1 t ADT: 11,500

570TH ST

Good

Over: SMALL CREEK

077371502, Cass, IA

Built 2014 Load: 42.1 t ADT: 51

VICTORIA RD

Good

Over: SEVEN MILE CREEK

074362001, Cass, IA

Built 2012 Load: 43.7 t ADT: 35

N16 OLIVE ST

Good

Over: BRANCH OF BUCK CREEK

077360902, Cass, IA

Built 2021 Load: 43.7 t ADT: 1,524

G16 BOSTON RD

Good

Over: BRANCH OF BUCK CREEK

077360901, Cass, IA

Built 2022 Load: 44.7 t ADT: 89

LOCAL - QUINCY

Good

Over: CREEK

075362801, Cass, IA

Built 2003 Load: 48.2 t ADT: 15

N16 610TH ST

Good

Over: BEAR BRANCH OF TURKEY CR

075360806, Cass, IA

Built 2022 Load: 48.3 t ADT: 50

620TH ST

Good

Over: TURKEY CREEK

076363302, Cass, IA

Built 2012 Load: 48.6 t ADT: 72

ALLEN ST

Good

Over: TURKEY CREEK

H60000500, Cass, IA

Built 1994 Load: 49.8 t ADT: 23

IA 83

Good

Over: DRAINAGE DITCH

0.6 MI. E OF S.R. N28, Cass, IA

Built 1987 Load: 51.0 t ADT: 2,120

FM - LEWIS

Good

Over: WATERWAY

075371504, Cass, IA

Built 1998 Load: 51.6 t ADT: 358

IA 92

Good

Over: BAUGHMANS CREEK

0.3 mi. E of Jct. IA 48, Cass, IA

Built 1992 Load: 52.7 t ADT: 1,470

JACKSON RD

Good

Over: TURKEY CREEK

076361406, Cass, IA

Built 2008 Load: 52.9 t ADT: 139

IA 48

Good

Over: NISHNA RIVER OVERFLOW

1.7 MI. S. OF JCT. US 6, Cass, IA

Built 1995 Load: 57.1 t ADT: 1,120

INDIAN CREEK ST

Good

Over: TRIB TO INDIAN CREEK

075370502, Cass, IA

Built 2021 Load: 60.6 t ADT: 71

FAIRVIEW ROAD

Good

Over: SMALL CREEK

077353501, Cass, IA

Built 2022 Load: 72.9 t ADT: 46

Read our methodology - how this data is sourced, computed, and verified.

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.