Total bridges
306
Public highway bridges in Adair County
County profile · official public datasets
Adair County, IA
306 public highway bridges tracked in the FHWA National Bridge Inventory: 46.7% rated Good, 39.9% Fair, 13.4% Poor.
- 306
- Public bridges
- 46.7%
- Good condition
- 13.4%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Adair County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 28%
- lowest Poor share in state
- 13.4%
- Poor-condition share
- 306
- public highway bridges
- 1983
- 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.
Adair County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Adair County ranks #28 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 13.4%). Adair County, Iowa contains 306 public highway bridges. Roughly 46.7% are rated “Good,” 39.9% “Fair,” and 13.4% “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.
Good condition
46.7%
143 of 306 rated 7-9
Fair condition
39.9%
122 of 306 rated 5-6
Poor condition
13.4%
41 of 306 rated 4 or below
In-state Poor-share rank
#28 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 306 NBI-tracked bridges by lowest applicable component rating.
Good 46.7% (143)
Fair 39.9% (122)
Poor 13.4% (41)
Adair County's Poor-condition bridges carry 1,794 vehicle crossings a day
That is 0.5% of the county's reported daily bridge traffic on 13.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 44 crossings a day against 485 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 306 of 306 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
40.5% of Adair County's bridges have passed the 50-year mark
124 of the 306 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 46.7% 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 21.6% of the county's Poor-condition bridge traffic
3RD ST over OVER ABANDON RR, built 1900, carries 387 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 41-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 1,794 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Adair County's bridges were built
306 bridges with a recorded construction year, grouped by decade
- 1900s 9
1900–1909
9 bridges
- 1910s 5
1910–1919
5 bridges
- 1920s 2
1920–1929
2 bridges
- 1930s 4
1930–1939
4 bridges
- 1940s 17
1940–1949
17 bridges
- 1950s
1950–1959
57 bridges
- 1960s 24
1960–1969
24 bridges
- 1970s 14
1970–1979
14 bridges
- 1980s 10
1980–1989
10 bridges
- 1990s 20
1990–1999
20 bridges
- 2000s
2000–2009
71 bridges
- 2010s
2010–2019
63 bridges
- 2020s 10
2020–2029
10 bridges
What this shows Construction peaked in the 2000s, when 71 of the county's bridges still in the inventory were built, which is 23.2% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).
How Adair County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Adair County in number of bridges, with their condition splits. Its 13.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 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 | 316 | 42.4% | 50.9% | 6.6% | 1985 |
| Adair County (this page) | 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 Adair 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 Adair County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (306 bridges here).
- La Paz County, AZ · 306 bridges
- Greene County, PA · 306 bridges
- Greene County, TN · 306 bridges
- Grant County, WA · 306 bridges
Similar average build year
Nearest mean year-built outside IA (1983 here).
- Dallas County, TX · avg 1983 · 3,230 bridges
- Bexar County, TX · avg 1983 · 2,342 bridges
- Sedgwick County, KS · avg 1983 · 1,333 bridges
- Will County, IL · avg 1983 · 649 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Good-condition bridges (143)
GIBBON AVE
GoodOver: I-80
3.0 MI. E OF Jct. SR N54, Adair, IA
Built 1958 Load: 18.6 t ADT: 26
FM
GoodOver: NORTH TURKEY CREEK
077321402, Adair, IA
Built 1985 Load: 20.5 t ADT: 60
TRENTON AVE
GoodOver: I-80
1.0 mi. W of Jct. SR P28, Adair, IA
Built 1958 Load: 21.2 t ADT: 113
LOCAL
GoodOver: STREAM
077313002, Adair, IA
Built 2006 Load: 22.0 t ADT: 35
LOCAL
GoodOver: PLUNGER CREEK
077302602, Adair, IA
Built 2008 Load: 22.3 t ADT: 30
IA 25
GoodOver: STREAM
6.2 mi. N of Jct. IA 92, Adair, IA
Built 1952 Load: 22.7 t ADT: 2,080
G67 330TH ST
GoodOver: STREAM
074303403, Adair, IA
Built 2003 Load: 23.2 t ADT: 15
LOCAL
GoodOver: SMALL
077323301, Adair, IA
Built 2005 Load: 24.2 t ADT: 5
LOCAL
GoodOver: GRAND RIVER
075300801, Adair, IA
Built 1958 Load: 24.9 t ADT: 30
FM
GoodOver: NORTH RIVER
077310301, Adair, IA
Built 1989 Load: 25.2 t ADT: 139
FALLOW AVE
GoodOver: NINE MILE CREEK
0.9 mi S of G27 on Fallow, Adair, IA
Built 2014 Load: 26.3 t ADT: 30
LOCAL
GoodOver: STREAM
076311803, Adair, IA
Built 2003 Load: 26.8 t ADT: 51
LOCAL
GoodOver: STREAM
076323101, Adair, IA
Built 2006 Load: 26.8 t ADT: 41
LOCAL
GoodOver: STREAM
076331601, Adair, IA
Built 2002 Load: 26.8 t ADT: 41
150TH ST
GoodOver: STREAM
077333101, Adair, IA
Built 2005 Load: 26.8 t ADT: 15
150TH ST
GoodOver: BRANCH OF NODAWAY RIVER
077333601, Adair, IA
Built 2005 Load: 26.8 t ADT: 21
LOCAL
GoodOver: BRANCH NODAWAY RIVER
077333602, Adair, IA
Built 2002 Load: 26.8 t ADT: 26
P33 HENRY WALLACE
GoodOver: THREE MILE CREEK
74301807, Adair, IA
Built 1989 Load: 27.4 t ADT: 1,374
LOCAL
GoodOver: STREAM
0.9 mi W of N54 on 210th, Adair, IA
Built 2004 Load: 27.9 t ADT: 21
170TH AVE
GoodOver: STREAM
76320980, Adair, IA
Built 2013 Load: 28.2 t ADT: 21
VICTOR AVE
GoodOver: STREAM
76301508, Adair, IA
Built 2013 Load: 28.2 t ADT: 41
LOCAL
GoodOver: CLARK BRANCH
074330503, Adair, IA
Built 1997 Load: 28.3 t ADT: 46
VINTON AVE
GoodOver: STREAM
074301506, Adair, IA
Built 2007 Load: 28.6 t ADT: 30
LOCAL
GoodOver: NODAWAY CREEK
076323602, Adair, IA
Built 2007 Load: 28.7 t ADT: 41
LOCAL
GoodOver: STREAM
076320902, Adair, IA
Built 2006 Load: 30.6 t ADT: 21
G61 310TH ST
GoodOver: THREE MILE CREEK
074301901, Adair, IA
Built 2003 Load: 31.8 t ADT: 379
IA 25
GoodOver: TURKEY CREEK
4.6 MI. S OF JCT. I-80, Adair, IA
Built 2018 Load: 32.4 t ADT: 2,080
IA 25
GoodOver: MIDDLE RIVER
1.2 MI. S OF I-80, Adair, IA
Built 2018 Load: 32.4 t ADT: 2,080
IA 92
GoodOver: CLARK BR OF W NODAWAY R
3.8 Mi. E. of Jct. IA 148, Adair, IA
Built 2010 Load: 32.4 t ADT: 920
IA 92
GoodOver: MARVEL CREEK
0.3 MI. W. OF CO. RD. P33, Adair, IA
Built 2020 Load: 32.4 t ADT: 1,540
I 80 EB
GoodOver: MIDDLE RIVER
1.4 mi. W of IA 25, Adair, IA
Built 2013 Load: 32.4 t ADT: 12,400
WB I-80
GoodOver: MIDDLE RIVER
1.4 mi. W of IA 25, Adair, IA
Built 2011 Load: 32.7 t ADT: 12,400
P33 HENRY WALLACE
GoodOver: CREEK
074303102, Adair, IA
Built 2001 Load: 32.7 t ADT: 1,673
FM
GoodOver: W FK MIDDLE NODAWAY RVR
075331004, Adair, IA
Built 1982 Load: 32.7 t ADT: 60
G53 270TH ST
GoodOver: NINE MILE RUN
0.3 mi E of IA25 on G53, Adair, IA
Built 2016 Load: 33.0 t ADT: 40
INDIAN AVE
GoodOver: STREAM
77323308, Adair, IA
Built 2012 Load: 33.6 t ADT: 15
G53 270TH ST
GoodOver: BRANCH OF NINE MILE RUN
1.5 mi E of IA 25 on G53, Adair, IA
Built 2016 Load: 33.7 t ADT: 26
LOCAL
GoodOver: RUTT BRANCH
076323201, Adair, IA
Built 2007 Load: 34.0 t ADT: 41
FM
GoodOver: MIDDLE NODAWAY RIVER
074332460, Adair, IA
Built 1978 Load: 34.1 t ADT: 249
LOCAL
GoodOver: BATTLE CREEK
075300602, Adair, IA
Built 2005 Load: 34.2 t ADT: 26
FM
GoodOver: MIDDLE NODAWAY RIVER
076320401, Adair, IA
Built 2002 Load: 34.3 t ADT: 89
330TH ST
GoodOver: LOCAL STREAM
0.1 mi W of P33 on 330th, Adair, IA
Built 2017 Load: 34.3 t ADT: 26
110TH ST
GoodOver: MIDDLE RIVER
3.1 mi E of N54 on 110th, Adair, IA
Built 2015 Load: 34.7 t ADT: 51
G61 310TH ST
GoodOver: UNNAMED CREEK
2.4 mi E of N72 on G61, Adair, IA
Built 2015 Load: 34.7 t ADT: 468
P17 NEVADA AVE
GoodOver: STREAM
074312902, Adair, IA
Built 2004 Load: 34.8 t ADT: 71
FM
GoodOver: NODAWAY RIVER
075333402, Adair, IA
Built 2004 Load: 35.6 t ADT: 79
N54 DELTA AVE
GoodOver: BRANCH OF NODAWAY RVR
2.5 mi N of G27 on N54, Adair, IA
Built 2013 Load: 35.9 t ADT: 349
GIBBON AVE
GoodOver: MIDDLE RIVER
0.2 mi S of Co Line, Adair, IA
Built 2016 Load: 36.0 t ADT: 15
FM
GoodOver: MIDDLE NODAWAY RIVER
074333402, Adair, IA
Built 2005 Load: 36.3 t ADT: 34
LEWIS AVE
GoodOver: NODAWAY CREEK
3.4 mi S of G35 on Lewis, Adair, IA
Built 2020 Load: 36.3 t ADT: 62
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.