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

LOCAL RD

Good

Over: MIDDLE RIVER

075270804, Madison, IA

Built 1999 Load: 37.6 t ADT: 180

270TH ST

Good

Over: DRAINAGE

752934, Madison, IA

Built 2012 Load: 37.6 t ADT: 26

FA-245TH ST

Good

Over: KEG CREEK

072420606, Mills, IA

Built 2003 Load: 37.6 t ADT: 1,425

FM-APPLEWOOD

Good

Over: KEG CREEK

073420503, Mills, IA

Built 1996 Load: 37.6 t ADT: 71

WEST ST

Good

Over: MCCANDLES DITCH

085463507, Monona, IA

Built 2020 Load: 37.6 t ADT: 56

730TH AVE

Good

Over: DRAINAGE

072161100, Monroe, IA

Built 2022 Load: 37.6 t ADT: 34

REDWOOD AVE

Good

Over: DRY RUN

095412602, O'Brien, IA

Built 2023 Load: 37.6 t ADT: 35

POLK AVE

Good

Over: DRY RUN CREEK

095412802, O'Brien, IA

Built 2021 Load: 37.6 t ADT: 30

J AVENUE

Good

Over: LONG BRANCH

067381502, Page, IA

Built 2006 Load: 37.6 t ADT: 15

IA 140

Good

Over: STREAM

0.1 mi. S of S Jct SR C66, Plymouth, IA

Built 1976 Load: 37.6 t ADT: 1,990

HEDGE AVE

Good

Over: BROKEN KETTLE CREEK

93473602, Plymouth, IA

Built 2014 Load: 37.6 t ADT: 11

2ND AVE

Good

Over: BIRDLAND DR

079243502, Polk, IA

Built 2023 Load: 37.6 t ADT: 17,517

NB US 65

Good

Over: OVER UP RR

1.9 MI. N OF N JCT. IA 5, Polk, IA

Built 1997 Load: 37.6 t ADT: 12,450

FM

Good

Over: WALNUT CREEK

074383301, Pottawattamie, IA

Built 1972 Load: 37.6 t ADT: 40

COTTONWOOD ROAD

Good

Over: SILVER CREEK

074410303, Pottawattamie, IA

Built 2009 Load: 37.6 t ADT: 15

ELMTREE ROAD

Good

Over: KEG CREEK

075422701, Pottawattamie, IA

Built 2001 Load: 37.6 t ADT: 15

RIVERROAD NORTH

Good

Over: PIGEON CREEK

075440306, Pottawattamie, IA

Built 2000 Load: 37.6 t ADT: 45

SYCAMORE ROAD

Good

Over: SILVER CREEK

077402701, Pottawattamie, IA

Built 1991 Load: 37.6 t ADT: 26

FM-COUGAR AVE

Good

Over: STREAM

077433407, Pottawattamie, IA

Built 1976 Load: 37.6 t ADT: 100

OTTER AVE

Good

Over: STREAM

088362004, Sac, IA

Built 2019 Load: 37.6 t ADT: 71

K30 EAGLE AVE

Good

Over: SMALL STREAM

094462902, Sioux, IA

Built 2019 Load: 37.6 t ADT: 638

IA 210

Good

Over: OVER UP RR

2.5 MILES E OF JCT I-35, Story, IA

Built 1939 Load: 37.6 t ADT: 1,920

ROCKWOOD AVE

Good

Over: MIDDLE 102 RIVER

070331302, Taylor, IA

Built 2019 Load: 37.6 t ADT: 29

LOCAL

Good

Over: SMALL STREAM

072290306, Union, IA

Built 2010 Load: 37.6 t ADT: 51

FM

Good

Over: GRAND RIVER

073283106, Union, IA

Built 1991 Load: 37.6 t ADT: 29

YELLOW AVE

Good

Over: LITTLE CEDAR CREEK

069081202, Van Buren, IA

Built 2014 Load: 37.6 t ADT: 35

50TH AVE

Good

Over: SOUTH RIVER

074250202, Warren, IA

Built 2002 Load: 37.6 t ADT: 21

55TH AVE

Good

Over: BR MIDDLE RIVER

076252306, Warren, IA

Built 2018 Load: 37.6 t ADT: 62

LOCAL

Good

Over: DD

090283403, Webster, IA

Built 2011 Load: 37.6 t ADT: 72

LOCAL

Good

Over: TURKEY RIVER

096090601, Winneshiek, IA

Built 2003 Load: 37.6 t ADT: 97

230TH ST

Good

Over: CREEK

0.5 MI E 325 Av, Winneshiek, IA

Built 2018 Load: 37.6 t ADT: 33

LOCAL

Good

Over: CANOE CREEK

099082208, Winneshiek, IA

Built 2001 Load: 37.6 t ADT: 78

LOCAL

Good

Over: SMALL STREAM

093182402, Butler, IA

Built 1995 Load: 37.7 t ADT: 41

LOCAL - 665TH

Good

Over: TURKEY CREEK

076350712, Cass, IA

Built 1991 Load: 37.7 t ADT: 62

LOCAL - JASPER

Good

Over: TURKEY CREEK

076362203, Cass, IA

Built 1988 Load: 37.7 t ADT: 91

SPICER AVE

Good

Over: STREAM

080013002, Cedar, IA

Built 1991 Load: 37.7 t ADT: 20

LOCAL C AVE.

Good

Over: SMALL CREEK

091422802, Cherokee, IA

Built 1998 Load: 37.7 t ADT: 20

US 20 EB

Good

Over: IOWA RIVER RR

0.4 MI WEST OF JCT SR S56, Hardin, IA

Built 2003 Load: 37.7 t ADT: 4,500

U.S. 20 WB

Good

Over: IOWA RIVER RR

0.4 MILES W OF JCT SR S56, Hardin, IA

Built 2003 Load: 37.7 t ADT: 4,500

LOCAL

Good

Over: OLD MANS CREEK

079100804, Iowa, IA

Built 1992 Load: 37.7 t ADT: 50

FM

Good

Over: N CEDAR CREEK

074192403, Marion, IA

Built 1994 Load: 37.7 t ADT: 110

LOCAL

Good

Over: BIG BEAR CREEK

080141402, Poweshiek, IA

Built 1991 Load: 37.7 t ADT: 45

COUNTY Y52

Good

Over: BRANCH MUD CREEK

080E23604, Scott, IA

Built 1991 Load: 37.7 t ADT: 1,934

FM

Good

Over: INDIAN CREEK

078372003, Shelby, IA

Built 1989 Load: 37.7 t ADT: 29

US 18

Good

Over: ROCK RIVER OVERFLOW

0.7 mi. W of Jct SR K24, Sioux, IA

Built 1989 Load: 37.7 t ADT: 3,040

US 63 SB

Good

Over: DME RR

1.6 mi. S of Jct. IA 149, Wapello, IA

Built 2007 Load: 37.7 t ADT: 3,000

FM

Good

Over: LITTLE SIOUX RIVER

089423404, Woodbury, IA

Built 2006 Load: 37.7 t ADT: 797

LOCAL ROAD

Good

Over: BOONE RIVER

093261601, Wright, IA

Built 1991 Load: 37.7 t ADT: 21

FM

Good

Over: CLARK BRANCH

074330510, Adair, IA

Built 1994 Load: 37.8 t ADT: 249

KIMBALL AVE

Good

Over: TRIB TO MILLER CREEK

87-13-15-02-10, Black Hawk, IA

Built 1989 Load: 37.8 t ADT: 432

Showing 13,551-13,600 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.