State profile · Above median Poor share

Iowa bridge safety

According to the Federal Highway Administration's 2024 National Bridge Inventory, condition ratings, load ratings, and Poor-condition shares for every public highway bridge in Iowa.

23,719
Public bridges
38.8%
Good condition
19.2%
Poor condition

Iowa holds 23,719 public highway bridges (#7 of 52 by inventory) with a 19.16% Poor share (#1 of 52 by Poor share).

That is 19.2% of the state's inventory, against an average of 7.5% across the 54 states and territories with Poor-rated bridges on file, which places it 53 of 54 ordered from the lowest Poor share upward. A bridge is rated Poor when its weakest applicable component scores 4 or below on the inspecting agency's 0-9 scale, so the category is a maintenance and funding signal rather than a closure order or a live crossing-safety verdict.

Inventory: FHWA NBI 2024 · last ETL August 2026

Total Bridges

23,719

Public highway bridges in Iowa

Good Condition

38.8%

9,213 bridges rated 7-9

-11.2pp vs 50% benchmark

Poor Condition

19.2%

4,544 bridges whose lowest applicable component is rated 0-4

11.6pp vs national avg 7.5%

Iowa vs national bridge condition

Iowa - Good condition share 38.8%
National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

Iowa - Poor-condition share 63.9%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.5%.

Iowa in the national condition pattern

Each point is a state or territory in the FHWA NBI; the highlighted point is this profile.

Inventory size and Poor-condition share are different measures: Iowa has 23,719 bridges and a 19.2% Poor-condition share in the 2024 NBI, rank #53 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold. Scatter plot of 54 data points. 0%10%20%30%40% 0k20k40k60k Public bridges in inventory (thousands) Poor-condition share (%) IA, Public bridges in inventory (thousands): 23.7k · Poor-condition share (%): 19.16%AL, Public bridges in inventory (thousands): 16.2k · Poor-condition share (%): 3.35%AK, Public bridges in inventory (thousands): 1.7k · Poor-condition share (%): 7.89%AZ, Public bridges in inventory (thousands): 8.6k · Poor-condition share (%): 1.15%AR, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 5.43%CA, Public bridges in inventory (thousands): 25.8k · Poor-condition share (%): 5.91%CO, Public bridges in inventory (thousands): 9k · Poor-condition share (%): 4.82%CT, Public bridges in inventory (thousands): 4.4k · Poor-condition share (%): 4.72%DE, Public bridges in inventory (thousands): 0.9k · Poor-condition share (%): 1.26%DC, Public bridges in inventory (thousands): 0.3k · Poor-condition share (%): 1.95%FL, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 2.79%GA, Public bridges in inventory (thousands): 15.1k · Poor-condition share (%): 1.59%GU, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 12.77%HI, Public bridges in inventory (thousands): 1.2k · Poor-condition share (%): 6.53%ID, Public bridges in inventory (thousands): 4.6k · Poor-condition share (%): 4.9%IL, Public bridges in inventory (thousands): 26.9k · Poor-condition share (%): 9.35%IN, Public bridges in inventory (thousands): 19.5k · Poor-condition share (%): 5.22%KS, Public bridges in inventory (thousands): 24.9k · Poor-condition share (%): 5.26%KY, Public bridges in inventory (thousands): 14.5k · Poor-condition share (%): 7.37%LA, Public bridges in inventory (thousands): 12.7k · Poor-condition share (%): 11.48%ME, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 15.41%MD, Public bridges in inventory (thousands): 5.5k · Poor-condition share (%): 4.56%MA, Public bridges in inventory (thousands): 5.3k · Poor-condition share (%): 8.88%MI, Public bridges in inventory (thousands): 11.4k · Poor-condition share (%): 11.27%MN, Public bridges in inventory (thousands): 13.5k · Poor-condition share (%): 4.44%MS, Public bridges in inventory (thousands): 16.7k · Poor-condition share (%): 6.03%MO, Public bridges in inventory (thousands): 24.6k · Poor-condition share (%): 8.95%MT, Public bridges in inventory (thousands): 5.2k · Poor-condition share (%): 6.81%NE, Public bridges in inventory (thousands): 15.4k · Poor-condition share (%): 7.9%NV, Public bridges in inventory (thousands): 2.1k · Poor-condition share (%): 1.14%NH, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 7.51%NJ, Public bridges in inventory (thousands): 6.8k · Poor-condition share (%): 6.01%NM, Public bridges in inventory (thousands): 4k · Poor-condition share (%): 4.51%NY, Public bridges in inventory (thousands): 17.6k · Poor-condition share (%): 9.43%NC, Public bridges in inventory (thousands): 19.2k · Poor-condition share (%): 6.76%ND, Public bridges in inventory (thousands): 4.3k · Poor-condition share (%): 10.98%OH, Public bridges in inventory (thousands): 26.7k · Poor-condition share (%): 4.74%OK, Public bridges in inventory (thousands): 22.9k · Poor-condition share (%): 7.7%OR, Public bridges in inventory (thousands): 8.3k · Poor-condition share (%): 4.61%PA, Public bridges in inventory (thousands): 23.3k · Poor-condition share (%): 12.58%PR, Public bridges in inventory (thousands): 2.4k · Poor-condition share (%): 13.92%RI, Public bridges in inventory (thousands): 0.8k · Poor-condition share (%): 15.2%SC, Public bridges in inventory (thousands): 9.5k · Poor-condition share (%): 6.17%SD, Public bridges in inventory (thousands): 5.9k · Poor-condition share (%): 16.36%TN, Public bridges in inventory (thousands): 20.4k · Poor-condition share (%): 4.41%TX, Public bridges in inventory (thousands): 56.7k · Poor-condition share (%): 1.23%UT, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 2.91%VT, Public bridges in inventory (thousands): 2.9k · Poor-condition share (%): 2.9%VI, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 29.17%VA, Public bridges in inventory (thousands): 14.1k · Poor-condition share (%): 3.39%WA, Public bridges in inventory (thousands): 8.5k · Poor-condition share (%): 5.45%WV, Public bridges in inventory (thousands): 7.3k · Poor-condition share (%): 18.64%WI, Public bridges in inventory (thousands): 14.4k · Poor-condition share (%): 6.52%WY, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 6.51%
Inventory size and Poor-condition share are different measures: Iowa has 23,719 bridges and a 19.2% Poor-condition share in the 2024 NBI, rank #53 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold.

Iowa vs all states by public bridge inventory

Where this state's FHWA NBI public-highway bridge count sits among every state and territory on PlainBridges

23,719 7th of 54 higher than 47 of 54 states

States and territories, banded by public bridge inventory size

Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source FHWA National Bridge Inventory · 2024

Read the rank neighborhood for Iowa

The highlighted point is Iowa: 23,719 bridges and 19.16% in Poor condition, rank #53 of 54 jurisdictions ordered from the lowest share upward. The five jurisdictions immediately above and below Iowa on that same Poor-share ordering:

  • South Dakota: 5,887 bridges · 16.36% Poor
  • West Virginia: 7,348 bridges · 18.64% Poor
  • Iowa: 23,719 bridges · 19.16% Poor
  • Virgin Islands: 24 bridges · 29.17% Poor

The full national sortable table lives on the rankings page.

Material families in Iowa

Exclusive FHWA material families across all 23,719 bridges in this state; continuous variants fold into the parent family. Orthogonal to the Poor-share scatter above.

Who maintains Iowa’s inventory

State agency holds 17.7% of the 23,719 public highway bridges filed under Iowa in the 2024 NBI, the agency-of-record split for this state, not a condition verdict.

When Iowa’s bridges were built

Pre-1950 construction accounts for 12.4% of the 23,719 bridges with a recorded original year in Iowa. Era bands are orthogonal to the Poor-share ranking above.

Condition Distribution

Iowa38.8%42%19.2%GoodFairPoor
Bridge inventory deck-condition mix - Iowa (FHWA NBI)

Counties (99)

Adair 306 Adams 186 Allamakee 197 Appanoose 183 Audubon 206 Benton 374 Black Hawk 489 Boone 135 Bremer 266 Buchanan 316 Buena Vista 156 Butler 289 Calhoun 197 Carroll 249 Cass 295 Cedar 301 Cerro Gordo 266 Cherokee 248 Chickasaw 302 Clarke 168 Clay 151 Clayton 256 Clinton 372 Crawford 301 Dallas 199 Davis 165 Decatur 197 Delaware 293 Des Moines 176 Dickinson 84 Dubuque 346 Emmet 78 Fayette 362 Floyd 213 Franklin 228 Fremont 179 Greene 168 Grundy 289 Guthrie 263 Hamilton 165 Hancock 138 Hardin 241 Harrison 217 Henry 173 Howard 210 Humboldt 87 Ida 182 Iowa 241 Jackson 246 Jasper 382 Jefferson 157 Johnson 372 Jones 231 Keokuk 183 Kossuth 267 Lee 214 Linn 506 Louisa 151 Lucas 195 Lyon 276 Madison 225 Mahaska 225 Marion 217 Marshall 304 Mills 184 Mitchell 167 Monona 162 Monroe 130 Montgomery 210 Muscatine 144 O'Brien 264 Osceola 185 Page 196 Palo Alto 135 Plymouth 432 Pocahontas 201 Polk 545 Pottawattamie 557 Poweshiek 248 Ringgold 217 Sac 224 Scott 291 Shelby 207 Sioux 449 Story 296 Tama 337 Taylor 220 Union 169 Van Buren 156 Wapello 190 Warren 239 Washington 207 Wayne 163 Webster 190 Winnebago 55 Winneshiek 342 Woodbury 455 Worth 116 Wright 182

Iowa vs nearby ranks

Adjacent states by Poor-condition share (lower share = better)

States are ranked by the share of bridges whose lowest applicable component rating is 4 or below. This describes recorded condition; it does not measure funding effectiveness or live crossing safety. States here sit immediately above and below Iowa on the same metric.

SD

South Dakota

16.36% top marginal rate
Structure
Progressive
Burden @ $100K
$5,887

WV

West Virginia

18.64% top marginal rate
Structure
Progressive
Burden @ $100K
$7,348
Selected

IA

Iowa

19.16% top marginal rate
Structure
Progressive
Burden @ $100K
$23,719

VI

Virgin Islands

29.17% top marginal rate
Structure
Progressive
Burden @ $100K
$24

Bridges Needing Most Attention in Iowa

Six lowest-condition bridges in Iowa, ranked by the portal's composite display score. Inspection intervals are risk-based under current NBIS rules.

MAIN ST

Poor

Over: IOWA RIVER

089211800, Hardin, IA

Built 1936 Load: 0.0 t ADT: 1,858

SO MAIN ST

Poor

Over: CASCADE LANDING

000000000, Des Moines, IA

Built 1896 Load: 0.0 t ADT: 743

E 13TH ST

Poor

Over: OVER I.C.E. RR

000000000, Scott, IA

Built 1900 Load: 0.0 t ADT: 358

EMERSON ST

Poor

Over: DRAINAGE

000000000, Madison, IA

Built 1965 Load: 0.0 t ADT: 396

1ST AVE S

Poor

Over: 21ST ST & RR

089282000, Webster, IA

Built 1968 Load: 0.0 t ADT: 9,860

1ST ST

Poor

Over: DRAINAGE

D60500515, Audubon, IA

Built 1930 Load: 0.0 t ADT: 9

All Bridges in Iowa

FM VINCENT AV

Fair

Over: SMALL STREAM

088071502, Buchanan, IA

Built 1955 Load: 32.4 t ADT: 137

LOCAL 255TH ST

Fair

Over: SMALL STREAM

088082305, Buchanan, IA

Built 2006 Load: 32.4 t ADT: 11

LOCAL 240TH ST

Fair

Over: LIME CR

088101401, Buchanan, IA

Built 1967 Load: 32.4 t ADT: 34

LOCAL 180TH ST.

Fair

Over: PRAIRIE CREEK

089071601, Buchanan, IA

Built 1997 Load: 32.4 t ADT: 20

FM

Fair

Over: SMALL STREAM

089082204, Buchanan, IA

Built 1970 Load: 32.4 t ADT: 59

FM

Fair

Over: SMALL STREAM

089082803, Buchanan, IA

Built 1960 Load: 32.4 t ADT: 34

175TH AVE

Fair

Over: SMALL STREAM

089100703, Buchanan, IA

Built 1995 Load: 32.4 t ADT: 33

FM

Fair

Over: DRAINAGE DITCH

090071003, Buchanan, IA

Built 1955 Load: 32.4 t ADT: 44

LOC 100TH ST

Fair

Over: STREAM

090090201, Buchanan, IA

Built 1995 Load: 32.4 t ADT: 128

DEAD END 115 ST

Fair

Over: SMALL STREAM

000000000, Buchanan, IA

Built 1968 Load: 32.4 t ADT: 11

310TH ST

Fair

Over: MEADOW CREEK

097362601, Clay, IA

Built 1999 Load: 32.4 t ADT: 30

240TH AVE

Fair

Over: LITTLE MEADOWS

097362802, Clay, IA

Built 1999 Load: 32.4 t ADT: 123

FM 280TH ST

Fair

Over: STONEY CREEK

097381001, Clay, IA

Built 1965 Load: 32.4 t ADT: 270

LOCAL 185 ST

Fair

Over: PLUM CREEK

089041603, Delaware, IA

Built 1986 Load: 32.4 t ADT: 20

CHESTERMAN RD

Fair

Over: CREEK

088E10203, Dubuque, IA

Built 2014 Load: 32.4 t ADT: 71

FM

Fair

Over: SMALL STREAM

091E13008, Dubuque, IA

Built 1895 Load: 32.4 t ADT: 45

FM 100 160TH ST

Fair

Over: BOONE RIVER

094260501, Hancock, IA

Built 1948 Load: 32.4 t ADT: 330

F20L EASTON TRAIL

Fair

Over: WILLOW CREEK

080420607, Harrison, IA

Built 2020 Load: 32.4 t ADT: 437

COUNTY RD E-16

Fair

Over: WET CREEK

086043501, Jones, IA

Built 1968 Load: 32.4 t ADT: 727

K60(INDIAN AVE)

Fair

Over: LITTLE ROCK RIVER

098440702, Lyon, IA

Built 1960 Load: 32.4 t ADT: 230

LOCAL SEC RD

Fair

Over: BARRY CREEK

095392102, O'Brien, IA

Built 1900 Load: 32.4 t ADT: 41

FM

Fair

Over: DD JT 22

094341901, Palo Alto, IA

Built 1975 Load: 32.4 t ADT: 350

LOCAL

Fair

Over: CHEQUEST CREEK

069112205, Van Buren, IA

Built 1958 Load: 32.4 t ADT: 35

LOCAL

Fair

Over: SMALL STREAM

077091104, Washington, IA

Built 1965 Load: 32.4 t ADT: 26

FM

Fair

Over: STREAM

089071902, Buchanan, IA

Built 1965 Load: 32.4 t ADT: 982

170TH STREET

Fair

Over: SMALL CREEK

085031719, Jones, IA

Built 2001 Load: 32.4 t ADT: 47

LOCAL ROAD

Fair

Over: CREEK

100431601, Lyon, IA

Built 2003 Load: 32.4 t ADT: 21

310TH STREET

Fair

Over: STREAM

087102301, Buchanan, IA

Built 2005 Load: 32.4 t ADT: 51

250TH ST

Fair

Over: UNNAMED CREEK

8808240100, Buchanan, IA

Built 2010 Load: 32.4 t ADT: 41

E HARTFORD AVE

Fair

Over: CREEK

078241300, Polk, IA

Built 1980 Load: 32.4 t ADT: 161

SYCAMORE ST

Fair

Over: BEE BRANCH

N OF E 15TH STREET, Dubuque, IA

Built 2011 Load: 32.4 t ADT: 2,147

MAIN ST

Fair

Over: UNIV BR DRY RUN CREEK

AT 18TH ST, Black Hawk, IA

Built 1962 Load: 32.4 t ADT: 9,191

CO RD G36

Fair

Over: US 218

At the Jct. of SR G36, Washington, IA

Built 2008 Load: 32.4 t ADT: 2,010

WESLEY PKWY

Fair

Over: TRI-VIEW & BNSF RR

At Jct. IA 12, Woodbury, IA

Built 2012 Load: 32.4 t ADT: 13,300

US 20 WB

Fair

Over: LITTLE SIOUX RIVER

0.4 mi. W of jct. IA 31, Woodbury, IA

Built 2016 Load: 32.4 t ADT: 3,250

I 29 NB

Fair

Over: BACON CREEK

3.0 MILES NORTH OF US 75, Woodbury, IA

Built 2016 Load: 32.4 t ADT: 18,900

I 29 NB

Fair

Over: FLOYD RIVER

3.5 Mi. N of N Jct. US 75, Woodbury, IA

Built 2016 Load: 32.4 t ADT: 17,200

I 29 NB

Fair

Over: FLOYD BLVD

3.0 mi. N of jct. U.S. 75, Woodbury, IA

Built 2018 Load: 32.4 t ADT: 15,400

I 29 SB

Fair

Over: PIERCE ST FRONTAGE RD

0.4 MI S. OF JCT. US 77, Woodbury, IA

Built 2018 Load: 32.4 t ADT: 21,100

I 29 IA 12 NB

Fair

Over: PIERCE ST FRONTAGE RD

0.4 MI. S OF JCT. US 77, Woodbury, IA

Built 2017 Load: 32.4 t ADT: 16,700

I 29 SB

Fair

Over: PERRY CREEK CONDUIT

I-29 Over Perry Creek, Woodbury, IA

Built 2019 Load: 32.4 t ADT: 16,450

I 29 NB IA 12 NB

Fair

Over: HAMILTON BLVD

0.6 mi. N of US 77, Woodbury, IA

Built 2016 Load: 32.4 t ADT: 15,700

US 18

Fair

Over: LITTLE SIOUX RIVER

2.1 mi. W of W Jct US 71, Clay, IA

Built 1930 Load: 32.5 t ADT: 2,560

F 50

Fair

Over: I-29

At JCT. SR F-50, Harrison, IA

Built 1967 Load: 32.5 t ADT: 608

IA 1

Fair

Over: RALSTON CREEK

0.6 MI. N OF N JCT. US 6, Johnson, IA

Built 1932 Load: 32.5 t ADT: 13,500

NB I-29

Fair

Over: KEG CREEK

0.7 MI. S OF S JCT. US 34, Mills, IA

Built 1971 Load: 32.5 t ADT: 6,850

IA 37

Fair

Over: WILLOW RIVER

1.2 mi. W of jct. SR E54, Monona, IA

Built 1959 Load: 32.5 t ADT: 620

US 6 & IA 21

Fair

Over: ROCK CREEK

0.7 MI E OF W JCT IA 21, Poweshiek, IA

Built 1956 Load: 32.5 t ADT: 1,610

US 52

Fair

Over: STREAM & TWIN SPRINGS RD

0.6 mi. N of Jct. IA 9, Winneshiek, IA

Built 1963 Load: 32.5 t ADT: 4,230

WB US 20

Fair

Over: LITTLE WHISKEY CREEK

3.4 mi. W of SR K42, Woodbury, IA

Built 1953 Load: 32.5 t ADT: 6,500

Showing 6,301-6,350 of 23,719 bridges

Related

All states → | National rankings → | Understanding conditions → | Retired SD term explained →
Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the FHWA National Bridge Inventory (NBI). Poor condition is an inspection-record category, not a closure or unsafe-to-cross designation. Consult the bridge owner for current status.

Understanding Bridge Conditions

How FHWA rates bridge condition on a 0-9 scale.

Check Your Daily Bridges

How to look up bridge condition data for bridges on your route.

Read our methodology — how this data is sourced, computed, and verified.

What to do with this

Use Iowa's inventory picture to drill to a county or a specific span.

NBI condition ratings are inventory snapshots, not live crossing-safety verdicts.

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Iowa Good/Fair/Poor shares and county rollups on this page are computed from the same NBI extract as the national boards; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.