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

175TH ST

Good

Over: CREEK

072100903, Jefferson, IA

Built 2022 Load: 34.7 t ADT: 90

H33 BROOKVILLE

Good

Over: BRANCH COON CREEK

072110303, Jefferson, IA

Built 2013 Load: 34.7 t ADT: 110

IA 1

Good

Over: OLD MANS CRK E OVERFLOW

0.8 MI. S, OF SR F52, Johnson, IA

Built 2020 Load: 34.7 t ADT: 4,890

IA 1

Good

Over: OLD MANS CRK E OVRFLW

0.8 mi S of SR F52, Johnson, IA

Built 2020 Load: 34.7 t ADT: 4,890

MADISON RD

Good

Over: BARTO CREEK

084022001, Jones, IA

Built 2021 Load: 34.7 t ADT: 26

SHAW RD

Good

Over: DIVISION CREEK

084041104, Jones, IA

Built 2020 Load: 34.7 t ADT: 671

170TH AVE

Good

Over: CREEK

069062906, Lee, IA

Built 2018 Load: 34.7 t ADT: 20

PALO MARSH RD

Good

Over: BEAR CREEK

084081604, Linn, IA

Built 1982 Load: 34.7 t ADT: 2,082

221ST STREET

Good

Over: OVER BNSF RR

072433304, Mills, IA

Built 2008 Load: 34.7 t ADT: 847

170TH ST

Good

Over: TRIB TO SOLDIER RIVER

084421103, Monona, IA

Built 2016 Load: 34.7 t ADT: 20

110TH ST

Good

Over: CREEK

078E11201, Muscatine, IA

Built 2018 Load: 34.7 t ADT: 176

FM

Good

Over: SO BR LITTLE FLOYD RIVER

096410302, O'Brien, IA

Built 2009 Load: 34.7 t ADT: 459

F34 NE 94TH AVE

Good

Over: DD #38

Polk County, Polk, IA

Built 2019 Load: 34.7 t ADT: 417

S14 NE YODER DR

Good

Over: DRAINAGE DITCH

.1 Mi. N. of NE 126th St, Polk, IA

Built 2020 Load: 34.7 t ADT: 967

OLD HWY 59

Good

Over: W FORK W NISH RIVER

081392406, Shelby, IA

Built 1994 Load: 34.7 t ADT: 300

K52

Good

Over: SMALL STREAM

096452602, Sioux, IA

Built 1978 Load: 34.7 t ADT: 1,257

LOCAL

Good

Over: SM STREAM

097450201, Sioux, IA

Built 2005 Load: 34.7 t ADT: 71

N DAKOTA AVE

Good

Over: ONION CREEK

084243204, Story, IA

Built 2014 Load: 34.7 t ADT: 1,197

K AVE

Good

Over: GIVEN CREEK

086151402, Tama, IA

Built 2014 Load: 34.7 t ADT: 26

180TH ST

Good

Over: COMPETINE CREEK

073120901, Wapello, IA

Built 2017 Load: 34.7 t ADT: 40

185TH ST

Good

Over: CREEK

0.5 MI E of Centennial Rd, Winneshiek, IA

Built 2021 Load: 34.7 t ADT: 50

LEE AVE

Good

Over: STREAM

086441303, Woodbury, IA

Built 2018 Load: 34.7 t ADT: 26

MICHIGAN AVE

Good

Over: BIG WRIGHT CREEK

088433406, Woodbury, IA

Built 2014 Load: 34.7 t ADT: 11

LOCAL

Good

Over: WOLF CREEK

088440702, Woodbury, IA

Built 1985 Load: 34.7 t ADT: 15

IA 31

Good

Over: STREAM

2.9 mi. S of jct. SR L36, Woodbury, IA

Built 2001 Load: 34.7 t ADT: 1,070

P17 NEVADA AVE

Good

Over: STREAM

074312902, Adair, IA

Built 2004 Load: 34.8 t ADT: 71

180TH STREET

Good

Over: WATERWAY

082E21801, Clinton, IA

Built 2007 Load: 34.8 t ADT: 30

NB US 61

Good

Over: DEVIL'S CREEK

2.5 mi. S of jct. IA 2, Lee, IA

Built 1999 Load: 34.8 t ADT: 3,850

180TH ST

Good

Over: BULL RUN

092471501, Plymouth, IA

Built 1985 Load: 34.8 t ADT: 15

CONCORD AVE

Good

Over: DRAINAGE

092482102, Plymouth, IA

Built 2000 Load: 34.8 t ADT: 26

FM

Good

Over: NISHNABOTNA RIVER

080353503, Audubon, IA

Built 1987 Load: 34.9 t ADT: 100

130TH ST

Good

Over: BUCK CREEK

093112003, Bremer, IA

Built 2019 Load: 34.9 t ADT: 20

LOCAL

Good

Over: FIELD STREAM

085360301, Carroll, IA

Built 2001 Load: 34.9 t ADT: 71

590TH ST

Good

Over: OVERFLOW

091393501, Cherokee, IA

Built 2003 Load: 34.9 t ADT: 5

FM RIVER RD.

Good

Over: BRANCH LITTLE SIOUX RVR

091403103, Cherokee, IA

Built 2008 Load: 34.9 t ADT: 748

GRACE ST

Good

Over: BOYER RIVER

000000000, Crawford, IA

Built 1997 Load: 34.9 t ADT: 150

LOCAL

Good

Over: S RACCOON RIVER

078290327, Dallas, IA

Built 1996 Load: 34.9 t ADT: 82

FM

Good

Over: SO RACOON RIVER

078290706, Dallas, IA

Built 2003 Load: 34.9 t ADT: 767

US 18 EB

Good

Over: FLOOD CREEK

0.2 mi. W of Jct. SR T26, Floyd, IA

Built 1998 Load: 34.9 t ADT: 5,350

US 18 WB

Good

Over: FLOOD CREEK

0.2 mi. W of jct. SR T26, Floyd, IA

Built 1998 Load: 34.9 t ADT: 5,350

FM

Good

Over: BOONE RIVER

089260104, Hamilton, IA

Built 2009 Load: 34.9 t ADT: 509

LOCAL

Good

Over: CREEK

088192304, Hardin, IA

Built 1992 Load: 34.9 t ADT: 10

LOCAL

Good

Over: SMALL STREAM

089192602, Hardin, IA

Built 1992 Load: 34.9 t ADT: 30

IA 14

Good

Over: BUCK CREEK

2.7 MI. S SR F62, Jasper, IA

Built 1971 Load: 34.9 t ADT: 3,360

US 34

Good

Over: MITCHELL CREEK

072102800, Jefferson, IA

Built 2009 Load: 34.9 t ADT: 4,360

FM

Good

Over: LICK CREEK

067072005, Lee, IA

Built 2008 Load: 34.9 t ADT: 200

FM

Good

Over: SUGAR CREEK

069062210, Lee, IA

Built 2008 Load: 34.9 t ADT: 420

NW 62ND AVE WB

Good

Over: BEAVER CREEK

000000000, Polk, IA

Built 2012 Load: 34.9 t ADT: 1,941

730TH AVE

Good

Over: MIDDLE MINERVA CREEK

085212502, Story, IA

Built 1983 Load: 34.9 t ADT: 26

LOCAL

Good

Over: SMALL STREAM

071303401, Union, IA

Built 1997 Load: 34.9 t ADT: 15

Showing 12,801-12,850 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.