Total bridges
316
Public highway bridges in Buchanan County
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.
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
- 1900s 2
1900–1909
2 bridges
- 1910s 2
1910–1919
2 bridges
- 1920s 4
1920–1929
4 bridges
- 1940s 5
1940–1949
5 bridges
- 1950s
1950–1959
42 bridges
- 1960s
1960–1969
41 bridges
- 1970s
1970–1979
35 bridges
- 1980s
1980–1989
42 bridges
- 1990s
1990–1999
25 bridges
- 2000s
2000–2009
59 bridges
- 2010s
2010–2019
55 bridges
- 2020s 4
2020–2029
4 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.
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.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Buchanan County (this page) | 316 | 42.4% | 50.9% | 6.6% | 1985 |
| Adair County | 306 | 46.7% | 39.9% | 13.4% | 1983 |
| Marshall County | 304 | 32.9% | 23.7% | 43.4% | 1970 |
| Chickasaw County | 302 | 42.1% | 30.1% | 27.8% | 1986 |
| Cedar County | 301 | 42.9% | 37.5% | 19.6% | 1983 |
| Crawford County | 301 | 42.5% | 48.5% | 9% | 1982 |
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).
- Jefferson County, NY · 316 bridges
- Cleveland County, OK · 316 bridges
- Gwinnett County, GA · 317 bridges
- Cherokee County, KS · 317 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.
Fair-condition bridges (161)
JACKSON ST.
FairOver: STREAM
000000000, Buchanan, IA
Built 1984 Load: 49.2 t ADT: 232
LOC KENTUCKY AV
FairOver: SMALL STREAM
090092302, Buchanan, IA
Built 2002 Load: 49.5 t ADT: 41
FM
FairOver: SMALL CREEK
090101605, Buchanan, IA
Built 1998 Load: 50.0 t ADT: 1,650
142ND ST
FairOver: W BRANCH BUFFALO CR
9008277423, Buchanan, IA
Built 2011 Load: 51.3 t ADT: 47
FM 280TH ST.
FairOver: SPRING CREEK
087100601, Buchanan, IA
Built 1952 Load: 51.6 t ADT: 246
LOCAL 250TH ST
FairOver: PINE CR
088082003, Buchanan, IA
Built 2004 Load: 52.5 t ADT: 82
LOCAL 170TH ST.
FairOver: PINE CREEK
089080801, Buchanan, IA
Built 2009 Load: 52.8 t ADT: 47
LOCAL
FairOver: BUFFALO CREEK
088070609, Buchanan, IA
Built 1998 Load: 52.9 t ADT: 51
FM
FairOver: PINE CREEK
088082105, Buchanan, IA
Built 1991 Load: 52.9 t ADT: 776
112TH ST
FairOver: BUCK CREEK
090100703, Buchanan, IA
Built 2001 Load: 52.9 t ADT: 25
LOCAL 290TH ST
FairOver: DRY CREEK
087070901, Buchanan, IA
Built 2003 Load: 72.6 t ADT: 5
Read our methodology - how this data is sourced, computed, and verified.
Related
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.