County profile · official public datasets

Buchanan County, IA

316 public highway bridges tracked in the FHWA National Bridge Inventory: 42.4% rated Good, 50.9% Fair, 6.6% Poor.

316
Public bridges
42.4%
Good condition
6.6%
Poor condition

The verdict

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

Buchanan County pairs a top-10% lowest Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 9%
lowest Poor share in state
6.6%
Poor-condition share
316
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.

Buchanan County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Buchanan County ranks #9 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.6%). Buchanan County, Iowa contains 316 public highway bridges. Roughly 42.4% are rated “Good,” 50.9% “Fair,” and 6.6% “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

316

Public highway bridges in Buchanan County

Good condition

42.4%

134 of 316 rated 7-9

Fair condition

50.9%

161 of 316 rated 5-6

Poor condition

6.6%

21 of 316 rated 4 or below

In-state Poor-share rank

#9 of 99

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

Condition distribution

Share of 316 NBI-tracked bridges by lowest applicable component rating.

Good
42.4% (134)
Fair
50.9% (161)
Poor
6.6% (21)

Buchanan County's Poor-condition bridges carry 10,438 vehicle crossings a day

That is 3.3% of the county's reported daily bridge traffic on 6.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 497 crossings a day against 1,087 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 316 of 316 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

34.5% of Buchanan County's bridges have passed the 50-year mark

109 of the 316 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 42.4% 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 25.6% of the county's Poor-condition bridge traffic

RACINE AVE over DRAINAGE DITCH, built 1953, carries 2,671 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 10,438 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Buchanan County's bridges were built

316 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 2000s, when 59 of the county's bridges still in the inventory were built, which is 18.7% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year is 1985, 6 years newer than the Iowa average of 1979.

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

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

The 5 Iowa counties nearest Buchanan County in number of bridges, with their condition splits. Its 6.6% Poor share is the 1st-lowest of these 6. Its average build year of 1985 against a peer-group mean of 1981 is in line with the group.

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

Bridge inventory size and condition shares for Buchanan County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Buchanan County (this page) 316 6.6%
Adair County 306 13.4%
Marshall County 304 43.4%
Chickasaw County 302 27.8%
Cedar County 301 19.6%
Crawford County 301 9%

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

Similar inventory size

Nearest county inventories outside IA (316 bridges here).

Similar average build year

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

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

All 316 Good 134 Fair 161 Poor 21

Good-condition bridges (134)

LOC GRANT AVE

Good

Over: SMALL STREAM

090093004, Buchanan, IA

Built 2005 Load: 42.1 t ADT: 91

US 20

Good

Over: DRAINAGE DITCH

4.6 mi. W of W jct. IA150, Buchanan, IA

Built 1980 Load: 42.4 t ADT: 10,100

FM 290TH ST

Good

Over: LIME CREEK

087101201, Buchanan, IA

Built 2004 Load: 42.8 t ADT: 344

W35 QUASQUETON AVE

Good

Over: SMALL CREEK

087081502, Buchanan, IA

Built 2019 Load: 43.3 t ADT: 1,159

HAYES ST

Good

Over: OTTER CREEK

000000000, Buchanan, IA

Built 2015 Load: 44.7 t ADT: 1,119

120TH ST

Good

Over: HUNTER CREEK

090091803, Buchanan, IA

Built 2000 Load: 44.7 t ADT: 1,100

IA 150

Good

Over: BEAR CREEK

3.3 MI. S of Jct. US 20, Buchanan, IA

Built 2009 Load: 45.3 t ADT: 4,650

OVERLAND AVE

Good

Over: SAND CREEK

087082102, Buchanan, IA

Built 1995 Load: 45.4 t ADT: 20

FM 250TH ST

Good

Over: LIME CREEK

088102301, Buchanan, IA

Built 1989 Load: 45.4 t ADT: 69

LOCAL

Good

Over: SMALL STREAM

089100703, Buchanan, IA

Built 1995 Load: 45.4 t ADT: 33

QUONSET AVE

Good

Over: BUFFALO CREEK

090081404, Buchanan, IA

Built 2000 Load: 45.4 t ADT: 29

FM 155TH ST.

Good

Over: SMALL STREAM

090083203, Buchanan, IA

Built 2004 Load: 45.4 t ADT: 344

FM

Good

Over: SMALL STREAM

089072201, Buchanan, IA

Built 2007 Load: 45.7 t ADT: 59

LOC QUINN AVE

Good

Over: BUFFALO CR EAST BRANCH

090080202, Buchanan, IA

Built 2010 Load: 46.0 t ADT: 16

D22 200TH ST

Good

Over: BUFFALO CREEK

088080105, Buchanan, IA

Built 2018 Load: 46.8 t ADT: 746

WB US 20

Good

Over: PINE CREEK

1.6 mi. W of jct. SR W40, Buchanan, IA

Built 1978 Load: 47.6 t ADT: 4,150

FM 310TH ST.

Good

Over: SAND CREEK

087082101, Buchanan, IA

Built 1995 Load: 48.2 t ADT: 35

FM

Good

Over: PRARIE CREEK

089072201, Buchanan, IA

Built 2007 Load: 48.2 t ADT: 59

105TH ST

Good

Over: OTTER CREEK

090090407, Buchanan, IA

Built 2000 Load: 48.2 t ADT: 26

IA 281

Good

Over: HUNTER CREEK

1.7 mi. W of Jct. IA 150, Buchanan, IA

Built 1986 Load: 49.9 t ADT: 2,330

FM THOMAS AVE

Good

Over: DRY CREEK

087073106, Buchanan, IA

Built 1989 Load: 50.0 t ADT: 59

LOCAL UNION AVE

Good

Over: DRY CREEK

087073204, Buchanan, IA

Built 1997 Load: 50.0 t ADT: 98

FM

Good

Over: W BR BUFFALO CREEK

090080506, Buchanan, IA

Built 2004 Load: 50.0 t ADT: 334

FM

Good

Over: W BR BUFFALO CR

090081601, Buchanan, IA

Built 2003 Load: 50.0 t ADT: 373

LOC 150TH ST

Good

Over: HUNTER CR

090093103, Buchanan, IA

Built 2006 Load: 50.0 t ADT: 135

IA 187

Good

Over: PRAIRIE CREEK

1.6 MI. N OF US #20, Buchanan, IA

Built 1989 Load: 50.7 t ADT: 1,960

WASHINGTON AVE

Good

Over: S FORK MAQUOKETA RIVER

090071404, Buchanan, IA

Built 2005 Load: 52.9 t ADT: 88

LOCAL

Good

Over: S FORK MAQUOKETA RIVER

090072303, Buchanan, IA

Built 1997 Load: 52.9 t ADT: 49

FM

Good

Over: BUFFALO CREEK

090081103, Buchanan, IA

Built 2004 Load: 52.9 t ADT: 432

FM

Good

Over: STREAM

090100702, Buchanan, IA

Built 1999 Load: 52.9 t ADT: 34

FM 290 ST.

Good

Over: BEAR CREEK

087090901, Buchanan, IA

Built 2004 Load: 56.4 t ADT: 344

FM

Good

Over: S FK MAQUOKETA RIVER

090070903, Buchanan, IA

Built 1990 Load: 58.1 t ADT: 44

VICTOR AVE

Good

Over: S FORK MAQUOKETA RIVER

9007100059, Buchanan, IA

Built 2016 Load: 80.7 t ADT: 41

130TH ST

Good

Over: HUNTER CREEK

9009198800, Buchanan, IA

Built 2016 Load: 80.7 t ADT: 15

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.