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

300TH ST

Good

Over: SMALL STREAM

0.9 Mi W of 560th, Story, IA

Built 2019 Load: 49.2 t ADT: 100

113TH ST

Good

Over: HARDIN-STORY DD 1

0.5 Mi E 710 Ave, Story, IA

Built 2018 Load: 49.2 t ADT: 15

LOCAL

Good

Over: LITTLE CEDAR CREEK

072130502, Wapello, IA

Built 1987 Load: 49.2 t ADT: 35

156TH ST

Good

Over: LITTLE WALNUT CREEK

P55000600, Dallas, IA

Built 2007 Load: 49.3 t ADT: 1,257

156TH ST

Good

Over: LITTLE WALNUT CREEK

P55000600, Dallas, IA

Built 2007 Load: 49.3 t ADT: 1,211

NEWBOLD DR

Good

Over: STREAM

75191405, Marion, IA

Built 2016 Load: 49.3 t ADT: 207

SE 6TH AVE

Good

Over: TRIB TO MUD CREEK

078221001, Polk, IA

Built 2000 Load: 49.3 t ADT: 159

310TH STREET

Good

Over: THREE MILE CREEK

074312401, Adair, IA

Built 2006 Load: 49.4 t ADT: 518

BACKBONE ST PK

Good

Over: MAQUOKETA RIVER

IN BACKBONE STATE PARK, Delaware, IA

Built 1989 Load: 49.4 t

FM

Good

Over: DRAINAGE

071080206, Jefferson, IA

Built 2001 Load: 49.4 t ADT: 390

NB I-35,EB I-80

Good

Over: UP RR

0.5 mi. E of jct. US 69, Polk, IA

Built 2000 Load: 49.4 t ADT: 41,550

IA 92

Good

Over: EAST NISHNABOTNA RIVER

1.4 MI. W OF JCT. IA 48, Pottawattamie, IA

Built 1999 Load: 49.4 t ADT: 1,180

US 18

Good

Over: DRY RUN CREEK

1.7 mi. W of S.R. K24, Sioux, IA

Built 2007 Load: 49.4 t ADT: 3,040

FM

Good

Over: FARMERS DITCH

088473603, Woodbury, IA

Built 1999 Load: 49.4 t ADT: 1,008

FM

Good

Over: LITTLE WHISKEY CREEK

088473603, Woodbury, IA

Built 1999 Load: 49.4 t ADT: 1,008

UNIVERSITY AVE

Good

Over: NORTH WALNUT CREEK

078250300, Polk, IA

Built 1983 Load: 49.5 t ADT: 11,490

H33 180TH ST

Good

Over: EAST NODAWAY RIVER

072321701, Adams, IA

Built 2015 Load: 49.6 t ADT: 409

180TH ST

Good

Over: BEAVER DAM CREEK

1400' E of Olive Ave, Cerro Gordo, IA

Built 2021 Load: 49.6 t ADT: 34

290TH ST

Good

Over: IDEAL CREEK

0.4 mi. east of Raven Ave, Cerro Gordo, IA

Built 2021 Load: 49.6 t ADT: 51

270TH AVE

Good

Over: SMALL STREAM

081E33604, Clinton, IA

Built 2017 Load: 49.6 t ADT: 30

120TH ST.

Good

Over: LITTLE VOLGA R

092091001, Fayette, IA

Built 1996 Load: 49.6 t ADT: 15

US 20

Good

Over: STREAM

2.0 MILES EAST OF SR T55, Grundy, IA

Built 1999 Load: 49.6 t ADT: 14,500

FM

Good

Over: MURRAY CREEK

094390808, O'Brien, IA

Built 1987 Load: 49.6 t ADT: 880

C66 310TH ST

Good

Over: LITTLE SIOUX RIVER

9043190110, Plymouth, IA

Built 2018 Load: 49.6 t ADT: 309

LOCAL

Good

Over: STREAM

071302501, Union, IA

Built 2004 Load: 49.6 t ADT: 11

FM

Good

Over: WEST PLATTE RIVER

072312902, Union, IA

Built 1998 Load: 49.6 t ADT: 29

IA 16

Good

Over: STUMP CREEK

3.3 mi W of Jct. SR V64, Van Buren, IA

Built 2003 Load: 49.6 t ADT: 1,190

LOCAL

Good

Over: CEDAR CREEK

073131707, Wapello, IA

Built 2002 Load: 49.6 t ADT: 15

PHEASANT AVE

Good

Over: CREEK

081340302, Audubon, IA

Built 2019 Load: 49.7 t ADT: 35

165TH ST

Good

Over: WAPSIPINICAN OVERFLOW

092120203, Bremer, IA

Built 2009 Load: 49.7 t ADT: 108

LOCAL

Good

Over: SMALL STREAM

071021706, Des Moines, IA

Built 2006 Load: 49.7 t ADT: 51

1995 150TH ST

Good

Over: EAST IOWA RIVER

094230701, Hancock, IA

Built 2005 Load: 49.7 t ADT: 41

FM

Good

Over: BRANCH WALNUT CREEK

073092308, Jefferson, IA

Built 2004 Load: 49.7 t ADT: 1,030

560TH ST

Good

Over: SOUTH OTTER CREEK

073231601, Lucas, IA

Built 2003 Load: 49.7 t ADT: 26

550TH ST

Good

Over: STREAM

073232103, Lucas, IA

Built 2006 Load: 49.7 t ADT: 21

VERMONT ST

Good

Over: STREAM

074182507, Marion, IA

Built 2019 Load: 49.7 t ADT: 15

UPTON ST

Good

Over: LONG BRANCH

074212407, Marion, IA

Built 2014 Load: 49.7 t ADT: 26

S37 NEVEDA ST

Good

Over: COON CREEK

075211701, Marion, IA

Built 2019 Load: 49.7 t ADT: 30

82ND AVE

Good

Over: TETER CREEK

076202004, Marion, IA

Built 2019 Load: 49.7 t ADT: 10

92ND AVE

Good

Over: TETER CREEK

076202104, Marion, IA

Built 2019 Load: 49.7 t ADT: 51

50TH AVE

Good

Over: UNNAMED STREAM

077210202, Marion, IA

Built 2015 Load: 49.7 t ADT: 21

FM

Good

Over: STREAM

072161407, Monroe, IA

Built 1998 Load: 49.7 t ADT: 140

FM

Good

Over: LITTLE SOAP CREEK

071141610, Wapello, IA

Built 2004 Load: 49.7 t ADT: 480

330TH ST

Good

Over: STREAM

0.3 mi E of P13 on 330th, Adair, IA

Built 2015 Load: 49.8 t ADT: 26

N53 DELTA AVE

Good

Over: STREAM

2.6 mi S of G61 on N53, Adair, IA

Built 2016 Load: 49.8 t ADT: 26

140TH ST

Good

Over: STREAM

0.2 mi E of NW S30-77-30, Adair, IA

Built 2016 Load: 49.8 t ADT: 11

LOCAL

Good

Over: NORTH RIVER

077303502, Adair, IA

Built 2004 Load: 49.8 t ADT: 26

320TH ST

Good

Over: UNNAMED STREAM

0.1 mi E of Lewis on 320, Adair, IA

Built 2015 Load: 49.8 t ADT: 21

FM

Good

Over: BEAVER CREEK

081340203, Audubon, IA

Built 1991 Load: 49.8 t ADT: 11

LOCAL

Good

Over: WHITE BREAST CREEK

072252604, Clarke, IA

Built 2004 Load: 49.8 t ADT: 40

Showing 15,701-15,750 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.