State profile · Above national median SD

Iowa bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in Iowa — drawn straight from the FHWA National Bridge Inventory.

20,753
Public bridges
36.5%
Good condition
20.0%
Poor condition
20.0%
Structurally deficient

Total Bridges

20,753

Public highway bridges in Iowa

Good Condition

36.5%

7,582 bridges rated 7-9

-13.5pp vs 50% benchmark

Poor Condition

20.0%

4,153 bridges rated 0-4

Structurally Deficient

20.0%

4,153 bridges flagged for repair priority

13.0pp vs national avg 7.0%

Iowa vs national bridge condition

Iowa — Good condition share 36.5%
National avg

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

Iowa — Structurally deficient share 66.7%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

Bridge inventory deck-condition mix — Iowa (FHWA NBI)

Iowa36.534476943092564%38.39444899532597%20.011564593070883%20.011564593070883%GoodFairPoorStructurally Deficient
Bridge inventory deck-condition mix — Iowa (FHWA NBI)

Counties (99)

Adair 208 Adams 147 Allamakee 170 Appanoose 159 Audubon 161 Benton 327 Black Hawk 411 Boone 119 Bremer 220 Buchanan 281 Buena Vista 140 Butler 261 Calhoun 171 Carroll 223 Cass 237 Cedar 265 Cerro Gordo 210 Cherokee 223 Chickasaw 268 Clarke 150 Clay 138 Clayton 214 Clinton 325 Crawford 242 Dallas 154 Davis 156 Decatur 178 Delaware 254 Des Moines 156 Dickinson 73 Dubuque 304 Emmet 70 Fayette 288 Floyd 195 Franklin 214 Fremont 133 Greene 150 Grundy 270 Guthrie 236 Hamilton 134 Hancock 128 Hardin 211 Harrison 162 Henry 144 Howard 193 Humboldt 70 Ida 164 Iowa 189 Jackson 209 Jasper 321 Jefferson 142 Johnson 317 Jones 215 Keokuk 152 Kossuth 256 Lee 185 Linn 428 Louisa 134 Lucas 186 Lyon 241 Madison 221 Mahaska 219 Marion 204 Marshall 283 Mills 170 Mitchell 160 Monona 125 Monroe 126 Montgomery 184 Muscatine 127 O'Brien 229 Osceola 176 Page 185 Palo Alto 114 Plymouth 407 Pocahontas 186 Polk 415 Pottawattamie 469 Poweshiek 221 Ringgold 206 Sac 188 Scott 212 Shelby 194 Sioux 429 Story 262 Tama 307 Taylor 220 Union 153 Van Buren 142 Wapello 160 Warren 231 Washington 203 Wayne 163 Webster 179 Winnebago 48 Winneshiek 317 Woodbury 379 Worth 89 Wright 168

Iowa vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient — the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below Iowa on the same metric.

54

West Virginia

16.02% top marginal rate
Structure
Progressive
Burden @ $100K
$7,679

46

South Dakota

16.24% top marginal rate
Structure
Progressive
Burden @ $100K
$5,905
Selected

19

Iowa

20.01% top marginal rate
Structure
Progressive
Burden @ $100K
$20,753

78

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 composite NBI rating. Each is inspected at least every 24 months.

270TH STREET

Structurally Deficient

Over: ROSE BRANCH

071343401, Adams, IA

Built 1976 Load: 2.7 t ADT: 79

LOCAL

Poor

Over: CREEK

078342601, Audubon, IA

Built 1935 Load: 2.7 t ADT: 21

KLINE RD

Structurally Deficient

Over: MUD CREEK

87-12-15-02-10, Black Hawk, IA

Built 1948 Load: 2.7 t ADT: 11

LOCAL - 700TH

Structurally Deficient

Over: TRIB TROUBLESOME CREEK

077351402, Cass, IA

Built 1983 Load: 2.7 t ADT: 11

LOCAL - DAYTONA

Structurally Deficient

Over: BUCK CREEK

077361903, Cass, IA

Built 1980 Load: 2.7 t ADT: 35

100TH ST.

Structurally Deficient

Over: UNION CREEK

083E20101, Clinton, IA

Built 1900 Load: 2.7 t ADT: 78

All Bridges in Iowa

G77 335TH ST

Good

Over: CEDAR CREEK

074143403, Mahaska, IA

Built 2022 Load: 32.4 t ADT: 70

ELBA AVE

Good

Over: MUCHAKINOCK CREEK

075170102, Mahaska, IA

Built 2016 Load: 32.4 t ADT: 90

G15 110TH ST

Good

Over: ELK CREEK

077170705, Mahaska, IA

Built 2021 Load: 32.4 t ADT: 45

N 17TH ST

Good

Over: BRANCH OF SPRING CREEK

075150700, Mahaska, IA

Built 2020 Load: 32.4 t ADT: 120

COOLIDGE ST

Good

Over: BNSF RR

077211901, Marion, IA

Built 2017 Load: 32.4 t ADT: 150

277TH ST

Good

Over: CLEAR CREEK

083203205, Marshall, IA

Built 2021 Load: 32.4 t ADT: 16

NORTH CENTER ST

Good

Over: IOWA RIVER OVERFLOW

084182306, Marshall, IA

Built 2021 Load: 32.4 t ADT: 737

NORTH CENTER ST

Good

Over: IOWA RIVER OVERFLOW

084182306, Marshall, IA

Built 2021 Load: 32.4 t ADT: 737

NORTH CENTER ST

Good

Over: IOWA RIVER

084182600, Marshall, IA

Built 2021 Load: 32.4 t ADT: 737

JESSUP AVE

Good

Over: MINERVA CREEK

084190304, Marshall, IA

Built 2023 Load: 32.4 t ADT: 62

SR E 18

Good

Over: IOWA RIVER

085191103, Marshall, IA

Built 2011 Load: 32.4 t ADT: 324

MORMON RIDGE RD

Good

Over: STREAM

085193402, Marshall, IA

Built 2021 Load: 32.4 t ADT: 15

W OLIVE ST

Good

Over: CREEK

083180300, Marshall, IA

Built 2013 Load: 32.4 t ADT: 1,205

IA 146

Good

Over: UP RR

0.5 Mi,South,US#30, Marshall, IA

Built 2019 Load: 32.4 t ADT: 2,160

330TH ST

Good

Over: NISHNABOTNA RIVER

071411502, Mills, IA

Built 2015 Load: 32.4 t ADT: 329

190TH ST

Good

Over: BNSF RR

000000000, Mills, IA

Built 2019 Load: 32.4 t ADT: 133

IA 9

Good

Over: SUGAR CREEK

1.2 mi. W of jct. US 218, Mitchell, IA

Built 2013 Load: 32.4 t ADT: 2,990

T34 JERSEY AVE

Good

Over: CREEK

1 Mi S 330th St, Mitchell, IA

Built 2016 Load: 32.4 t ADT: 69

317TH ST

Good

Over: CREEK

0.1 Mi E Jersey Ave, Mitchell, IA

Built 2016 Load: 32.4 t ADT: 11

IA 175

Good

Over: MAPLE RIVER

1.0 MI. W. OF IA 141, Monona, IA

Built 2022 Load: 32.4 t ADT: 1,200

IA 183

Good

Over: NATURAL STREAM

3.5 mi. S of Co. Rd. E-54, Monona, IA

Built 2015 Load: 32.4 t ADT: 580

IA 183

Good

Over: STREAM

1.1 mi. S of IA 37, Monona, IA

Built 2011 Load: 32.4 t ADT: 420

NB I-29

Good

Over: CLEGHORN CREEK

4.5 mi. S of IA 175, Monona, IA

Built 2012 Load: 32.4 t ADT: 7,250

NB I-29

Good

Over: ROBINSON DITCH

4.1 mi. S of jct. IA 141, Monona, IA

Built 2011 Load: 32.4 t ADT: 7,800

TEAK AVE

Good

Over: LOCAL STREAM

082422704, Monona, IA

Built 2017 Load: 32.4 t ADT: 29

E54

Good

Over: MONONA-HARRISON DITCH

083443203, Monona, IA

Built 2015 Load: 32.4 t ADT: 289

E54

Good

Over: LITTLE SIOUX RIVER

083443301, Monona, IA

Built 2015 Load: 32.4 t ADT: 289

TULIP AVE

Good

Over: UPPER SOLDIER RIVER

084423518, Monona, IA

Built 2011 Load: 32.4 t ADT: 159

T55 720TH ST

Good

Over: STREAM

072161004, Monroe, IA

Built 2016 Load: 32.4 t ADT: 15

625TH AVE

Good

Over: STREAM

072171808, Monroe, IA

Built 2016 Load: 32.4 t ADT: 60

H35 196TH ST

Good

Over: STREAM

072172003, Monroe, IA

Built 2015 Load: 32.4 t ADT: 350

S65 515TH AVE

Good

Over: ENGLISH CREEK

072190804, Monroe, IA

Built 2018 Load: 32.4 t ADT: 70

T55 720TH AVE

Good

Over: MILLER CREEK

073161403, Monroe, IA

Built 2021 Load: 32.4 t ADT: 180

500TH AVE

Good

Over: CARRUTHERS CREEK

073190602, Monroe, IA

Built 2014 Load: 32.4 t ADT: 45

H54 265TH ST

Good

Over: WEST NODAWAY

071362803, Montgomery, IA

Built 2017 Load: 32.4 t ADT: 300

230TH ST

Good

Over: WALNUT CREEK

071390801, Montgomery, IA

Built 2019 Load: 32.4 t ADT: 15

M37 BOXELDER AVE

Good

Over: BNSF RR

072392804, Montgomery, IA

Built 2014 Load: 32.4 t ADT: 249

210TH ST

Good

Over: WALNUT CREEK

072393305, Montgomery, IA

Built 2019 Load: 32.4 t ADT: 30

H20 (150TH ST)

Good

Over: NISHNABOTNA RIVER

073383403, Montgomery, IA

Built 2013 Load: 32.4 t ADT: 159

US 6

Good

Over: WEST WAPSINONOC CREEK

0.2 MI. E OF SEC. RD. X34, Muscatine, IA

Built 2013 Load: 32.4 t ADT: 4,320

BURLINGTON RD

Good

Over: KINCAID CREEK

076020619, Muscatine, IA

Built 2015 Load: 32.4 t ADT: 260

180TH ST

Good

Over: PINE CREEK

077E11803, Muscatine, IA

Built 2016 Load: 32.4 t ADT: 45

SAULSBURY RD

Good

Over: CHICKEN CREEK

077030206, Muscatine, IA

Built 2013 Load: 32.4 t ADT: 145

N ISETT AVE

Good

Over: SMALL CREEK

078023502, Muscatine, IA

Built 2019 Load: 32.4 t ADT: 100

WILSON AVE

Good

Over: SMALL UNNAMED CREEK

097391102, O'Brien, IA

Built 2016 Load: 32.4 t ADT: 21

MCKINLEY AVE

Good

Over: STREAM

99420602, Osceola, IA

Built 2011 Load: 32.4 t ADT: 15

120TH ST

Good

Over: OTTER CREEK

100412001, Osceola, IA

Built 2011 Load: 32.4 t ADT: 15

J53 265TH ST

Good

Over: WEST NODAWAY RIVER

068363107, Page, IA

Built 2017 Load: 32.4 t ADT: 219

A AVENUE

Good

Over: NISHNABOTNA RIVER

069390802, Page, IA

Built 2020 Load: 32.4 t ADT: 110

J 20 140TH STREET

Good

Over: WEST TARKIO RIVER

070382701, Page, IA

Built 2021 Load: 32.4 t ADT: 837

Showing 10,851-10,900 of 20,753 bridges

Related

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

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). A "structurally deficient" rating is a repair-priority signal, not a closure or unsafe-to-cross designation. Consult a qualified civil engineer before making decisions based on this data.

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.