County profile · official public datasets

Worth County, IA

116 public highway bridges tracked in the FHWA National Bridge Inventory: 35.3% rated Good, 48.3% Fair, 16.4% Poor.

116
Public bridges: 35.3%
Good condition: 16.4%
Poor condition

The verdict

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

Worth County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 36%
lowest Poor share in state: 16.4%
Poor-condition share: 116
public highway bridges: 1970
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.

Worth County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Worth County ranks #36 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 16.4%). Worth County, Iowa contains 116 public highway bridges. Roughly 35.3% are rated “Good,” 48.3% “Fair,” and 16.4% “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

116

Public highway bridges in Worth County

Good condition

35.3%

41 of 116 rated 7-9

Fair condition

48.3%

56 of 116 rated 5-6

Poor condition

16.4%

19 of 116 rated 4 or below

In-state Poor-share rank

#36 of 99

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

Condition distribution

Share of 116 NBI-tracked bridges by lowest applicable component rating.

Good

35.3% (41)

Fair

48.3% (56)

Poor

16.4% (19)

Worth County's Poor-condition bridges carry 3,639 vehicle crossings a day

That is 2.7% of the county's reported daily bridge traffic on 16.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 192 crossings a day against 885 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 116 of 116 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

66.4% of Worth County's bridges have passed the 50-year mark

77 of the 116 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 35.3% 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 51.3% of the county's Poor-condition bridge traffic

CENTRAL AVE N over SHELLROCK RIVER, built 1950, carries 1,868 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 19-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 3,639 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

4
1910s

4
1920s

5
1940s

8
1950s

18
1960s

15
1970s

28
1980s

3
1990s

9
2000s

11
2010s

8
2020s

3

What this shows Construction peaked in the 1970s, when 28 of the county's bridges still in the inventory were built, which is 24.1% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1970, 9 years older than the Iowa average of 1979.

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

The 5 Iowa counties nearest Worth County in number of bridges, with their condition splits. Its 16.4% Poor share is the 1st-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1973 is in line with the group.

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

Bridge inventory size and condition shares for Worth County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Muscatine County	144	34.7%	43.8%	21.5%	1979
Hancock County	138	39.9%	39.9%	20.3%	1981
Boone County	135	27.4%	43%	29.6%	1955
Palo Alto County	135	23%	58.5%	18.5%	1973
Monroe County	130	26.2%	49.2%	24.6%	1977
Worth County (this page)	116	35.3%	48.3%	16.4%	1970

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

Similar inventory size

Nearest county inventories outside IA (116 bridges here).

Howard County, AR · 116 bridges
Cassia County, ID · 116 bridges
Sheridan County, KS · 116 bridges
Caldwell County, KY · 116 bridges

Similar average build year

Nearest mean year-built outside IA (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
San Luis Obispo County, CA · avg 1970 · 401 bridges

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

All 116 Good 41 Fair 56 Poor 19

Fair-condition bridges (56)

Sort:

Worth County Bridge Snapshot

Condition distribution

Worth County's Poor-condition bridges carry 3,639 vehicle crossings a day

66.4% of Worth County's bridges have passed the 50-year mark

One structure carries 51.3% of the county's Poor-condition bridge traffic

How Worth 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

Fair-condition bridges (56)

CO RD 105

2ND AVE S

SWALLOW

S62 CO RD 105

370TH

350TH

495TH

410TH

NETTLE

IA 9

NUTHATCH

340TH

CO RD 105

IA 9

CO RD 105

367TH

CO RD 105

CO RD 105

VINE

355TH

A 27

FM RD A-39

CO RD 105

A 15

US 65

SB I 35

DOGWOOD

375TH

IA 9

NB I 35

IA 9

CO RD 105

THRUSH

WHEELERWOOD

VINE

SY RD A-38

CO RD 105

WHEELERWOOD

490TH

KING BIRD

I-35

500TH

THRUSH

WHEELERWOOD

US 65

DOGWOOD

430 TH

CO RD 105

SR 105

CO RD 105

Related