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

Good

Over: UPPER IOWA RIVER

100103507, Winneshiek, IA

Built 1986 Load: 26.8 t ADT: 70

LOCAL

Good

Over: HICKORY CREEK

096052303, Allamakee, IA

Built 1982 Load: 26.9 t ADT: 39

LOCAL RD

Good

Over: LEWIS JONES CREEK

098051404, Allamakee, IA

Built 2002 Load: 26.9 t ADT: 39

YOUNG RD

Good

Over: POYNER CREEK

88-12-10-05-10, Black Hawk, IA

Built 1992 Load: 26.9 t ADT: 148

E WASHBURN RD

Good

Over: CEDAR RIVER OVERFLOW

88-12-28-03-10, Black Hawk, IA

Built 1979 Load: 26.9 t ADT: 1,571

IA 27

Good

Over: BR DRY RUN CREEK

2.9 MI. S JCT. U.S. 218, Black Hawk, IA

Built 1993 Load: 26.9 t ADT: 20,900

LOCAL

Good

Over: SMALL

092111602, Bremer, IA

Built 2010 Load: 26.9 t ADT: 15

248TH ST

Good

Over: CREEK

091141709, Bremer, IA

Built 2007 Load: 26.9 t ADT: 70

KILLDEER AVE

Good

Over: CREEK

093133502, Bremer, IA

Built 2006 Load: 26.9 t ADT: 26

425TH AVE

Good

Over: CREEK

081E60404, Clinton, IA

Built 1970 Load: 26.9 t ADT: 1,241

NUTHATCH AVE

Good

Over: TRIB N CHEQUEST LAKE CR

069130506, Davis, IA

Built 2019 Load: 26.9 t ADT: 71

N AVE

Good

Over: LITTLE VOLGA RIVER

092092502, Fayette, IA

Built 2000 Load: 26.9 t ADT: 70

AGATE RD

Good

Over: TURKEY RIVER OVER FLOW

094071311, Fayette, IA

Built 1996 Load: 26.9 t ADT: 599

US 18

Good

Over: DRAINAGE DITCH

5.6 miles E of Iowa #14, Floyd, IA

Built 1987 Load: 26.9 t ADT: 2,110

LOCAL

Good

Over: SMALL UN-NAMED CREEK

094403102, O'Brien, IA

Built 1978 Load: 26.9 t ADT: 62

WARBLER AVE

Good

Over: JORDAN CREEK

09539330210, O'Brien, IA

Built 2016 Load: 26.9 t ADT: 26

LOCAL

Good

Over: LITTLE WATERMAN CREEK

096402502, O'Brien, IA

Built 2006 Load: 26.9 t ADT: 21

IA 2

Good

Over: WEST TARKIO RIVER

0.6 MI. E OF JCT. SR M41, Page, IA

Built 1991 Load: 26.9 t ADT: 2,650

200TH ST

Good

Over: CLEAR CREEK

9244251104000, Plymouth, IA

Built 2023 Load: 26.9 t ADT: 45

NW 54TH AVE

Good

Over: DRAINAGE DISTRICT 1

0107924, Polk, IA

Built 2011 Load: 26.9 t ADT: 956

300TH ST

Good

Over: E BR KEG CREEK

078403001, Shelby, IA

Built 2020 Load: 26.9 t ADT: 29

FM

Good

Over: WAPSINICON RIVER

082011102, Cedar, IA

Built 2010 Load: 27.0 t ADT: 70

390TH AVE

Good

Over: STREAM

082E52502, Clinton, IA

Built 1958 Load: 27.0 t ADT: 62

FM

Good

Over: IOWA RIVER

083160906, Tama, IA

Built 1954 Load: 27.0 t ADT: 206

FM

Good

Over: CREEK

068323601, Taylor, IA

Built 1994 Load: 27.0 t ADT: 34

LOCAL

Good

Over: SPRING CK

086112002, Benton, IA

Built 2002 Load: 27.1 t ADT: 60

WHITETAIL AVE

Good

Over: CREEK

093110202, Bremer, IA

Built 2020 Load: 27.1 t ADT: 33

GRANITE AVE

Good

Over: FIELD STREAM

084350701, Carroll, IA

Built 2011 Load: 27.1 t ADT: 60

LOCAL

Good

Over: SILVER CREEK

081210701, Jasper, IA

Built 2002 Load: 27.1 t ADT: 35

LOCAL

Good

Over: HONEY CREEK

076053605, Louisa, IA

Built 1989 Load: 27.1 t ADT: 26

IA 183

Good

Over: OVERFLOW CHANNEL

4.8 mi. S of SR E54, Monona, IA

Built 2008 Load: 27.1 t ADT: 580

LOCAL

Good

Over: MUD CREEK

0894406, Woodbury, IA

Built 2008 Load: 27.1 t ADT: 15

LOCAL

Good

Over: PAINT CREEK

097050501, Allamakee, IA

Built 2002 Load: 27.2 t ADT: 59

BECK RD

Good

Over: MILLER CREEK

87-13-17-02-10, Black Hawk, IA

Built 1997 Load: 27.2 t ADT: 20

US 61

Good

Over: STREAM

6.7 MI. N OF N JCT. US 30, Clinton, IA

Built 1996 Load: 27.2 t ADT: 9,600

FM

Good

Over: CREEK

000000000, Dubuque, IA

Built 2009 Load: 27.2 t ADT: 668

FM

Good

Over: SMALL STREAM

078311106, Guthrie, IA

Built 1990 Load: 27.2 t ADT: 60

IA 17

Good

Over: PRAIRIE CREEK

2.9 mi. S of Jct. US 18, Hancock, IA

Built 1991 Load: 27.2 t ADT: 1,090

LOCAL

Good

Over: BRANCH MITCHELL CREEK

072102801, Jefferson, IA

Built 1983 Load: 27.2 t ADT: 80

100TH AVENUE

Good

Over: WAPSIPINICON RIVER

083021504, Jones, IA

Built 2003 Load: 27.2 t ADT: 69

LOCAL

Good

Over: PLESSIS CREEK

097402501, O'Brien, IA

Built 1999 Load: 27.2 t ADT: 30

4TH AVE.E

Good

Over: WILLOW CREEK

000000000, Plymouth, IA

Built 1993 Load: 27.2 t ADT: 851

250TH ST

Good

Over: STREAM

091122401, Bremer, IA

Built 2016 Load: 27.3 t ADT: 59

FM

Good

Over: BEAVER CREEK

081281201, Dallas, IA

Built 1985 Load: 27.3 t ADT: 190

175TH ST

Good

Over: BR LITTLE WAPSIPINICON

098143607, Howard, IA

Built 1955 Load: 27.3 t ADT: 11

LOCAL

Good

Over: ENGLISH CREEK

075191607, Marion, IA

Built 1982 Load: 27.3 t ADT: 278

FM

Good

Over: LITTLE FLOYD RIVER

096421002, O'Brien, IA

Built 1987 Load: 27.3 t ADT: 1,337

130TH ST

Good

Over: OTTER CREEK

100413001, Osceola, IA

Built 2013 Load: 27.3 t ADT: 15

FM

Good

Over: SILVER CREEK

095342306, Palo Alto, IA

Built 2002 Load: 27.3 t ADT: 769

FM K-42

Good

Over: MINK CREEK

092461502, Plymouth, IA

Built 1985 Load: 27.3 t ADT: 359

Showing 9,751-9,800 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.