County profile · official public datasets

Davis County, IA

165 public highway bridges tracked in the FHWA National Bridge Inventory: 44.8% rated Good, 29.7% Fair, 25.5% Poor.

165
Public bridges: 44.8%
Good condition: 25.5%
Poor condition

The verdict

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

Davis County pairs a higher-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

73rd
of 99 on Poor share: 25.5%
Poor-condition share: 165
public highway bridges: 1985
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.

Davis County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Davis County ranks #73 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 25.5%). Davis County, Iowa contains 165 public highway bridges. Roughly 44.8% are rated “Good,” 29.7% “Fair,” and 25.5% “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

165

Public highway bridges in Davis County

Good condition

44.8%

74 of 165 rated 7-9

Fair condition

29.7%

49 of 165 rated 5-6

Poor condition

25.5%

42 of 165 rated 4 or below

In-state Poor-share rank

#73 of 99

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

Condition distribution

Share of 165 NBI-tracked bridges by lowest applicable component rating.

Good

44.8% (74)

Fair

29.7% (49)

Poor

25.5% (42)

Davis County's Poor-condition bridges carry 8,235 vehicle crossings a day

That is 15.5% of the county's reported daily bridge traffic on 25.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 196 crossings a day against 182 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 163 of 165 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

43% of Davis County's bridges have passed the 50-year mark

71 of the 165 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 44.8% 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 15.3% of the county's Poor-condition bridge traffic

FM over FOX RIVER, built 1973, carries 1,260 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 42-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 8,235 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1910s

1
1920s

1
1940s

10
1950s

21
1960s

18
1970s

27
1980s

10
1990s

13
2000s

18
2010s

32
2020s

13

What this shows Construction peaked in the 2010s, when 32 of the county's bridges still in the inventory were built, which is 19.4% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year is 1985, 6 years newer than the Iowa average of 1979.

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

The 5 Iowa counties nearest Davis County in number of bridges, with their condition splits. Its 25.5% Poor share is the 5th-lowest of these 6. Its average build year of 1985 against a peer-group mean of 1978 is 7 years newer.

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

Bridge inventory size and condition shares for Davis County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Clarke County	168	27.4%	41.1%	31.5%	1977
Greene County	168	35.1%	50%	14.9%	1973
Mitchell County	167	47.3%	42.5%	10.2%	1980
Hamilton County	165	39.4%	40%	20.6%	1970
Davis County (this page)	165	44.8%	29.7%	25.5%	1985
Wayne County	163	44.2%	37.4%	18.4%	1989

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

Similar inventory size

Nearest county inventories outside IA (165 bridges here).

Cleburne County, AL · 165 bridges
Randolph County, AL · 165 bridges
Plumas County, CA · 165 bridges
Leon County, FL · 165 bridges

Similar average build year

Nearest mean year-built outside IA (1985 here).

Hillsborough County, FL · avg 1985 · 840 bridges
Lancaster County, NE · avg 1985 · 661 bridges
Nueces County, TX · avg 1985 · 528 bridges
Grayson County, TX · avg 1985 · 513 bridges

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

All 165 Good 74 Fair 49 Poor 42

All bridges (165)

Sort:

Davis County Bridge Snapshot

Condition distribution

Davis County's Poor-condition bridges carry 8,235 vehicle crossings a day

43% of Davis County's bridges have passed the 50-year mark

One structure carries 15.3% of the county's Poor-condition bridge traffic

How Davis 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 (165)

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