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

N 14 (V AVE)

Good

Over: STREAM

068361502, Page, IA

Built 2012 Load: 32.7 t ADT: 270

240TH STREET

Good

Over: WEST MILL CREEK

068372001, Page, IA

Built 1989 Load: 32.7 t ADT: 11

K AVENUE

Good

Over: BUCK CREEK

068381404, Page, IA

Built 1997 Load: 32.7 t ADT: 29

160TH STREET

Good

Over: MIDDLE TARKIO RIVER

069380201, Page, IA

Built 1987 Load: 32.7 t ADT: 29

G AVENUE

Good

Over: STREAM

069383202, Page, IA

Built 1997 Load: 32.7 t ADT: 26

J-28/170TH ST

Good

Over: JONES CREEK

069391101, Page, IA

Built 1992 Load: 32.7 t ADT: 190

B AVENUE

Good

Over: FOURMILE CREEK

069392102, Page, IA

Built 1988 Load: 32.7 t ADT: 60

C AVENUE

Good

Over: FOUR MILE CREEK

069392202, Page, IA

Built 1989 Load: 32.7 t ADT: 89

P AVENUE

Good

Over: STREAM

070370202, Page, IA

Built 2022 Load: 32.7 t ADT: 5

D AVENUE

Good

Over: STREAM

069390204, Page, IA

Built 1987 Load: 32.7 t ADT: 60

T AVENUE

Good

Over: STREAM

069362906, Page, IA

Built 1990 Load: 32.7 t ADT: 40

US 75

Good

Over: DRY CREEK

2.0 mi S of SR C44, Plymouth, IA

Built 1972 Load: 32.7 t ADT: 14,000

FM K-49

Good

Over: DRAINAGE

091451002, Plymouth, IA

Built 1975 Load: 32.7 t ADT: 1,017

170TH ST (SDB)

Good

Over: DRAINAGE

1.0 mi N of jct IA 3, Plymouth, IA

Built 2004 Load: 32.7 t ADT: 469

190TH ST

Good

Over: DRAINAGE

9246220210, Plymouth, IA

Built 1935 Load: 32.7 t ADT: 359

JUNIPER AVE

Good

Over: DRAINAGE

092462304, Plymouth, IA

Built 2000 Load: 32.7 t ADT: 34

QUEST AVE

Good

Over: WILLOW CREEK

093430702, Plymouth, IA

Built 2004 Load: 32.7 t ADT: 30

L-22

Good

Over: W FORK LITTLE SIOUX RIV

093432502, Plymouth, IA

Built 1974 Load: 32.7 t ADT: 210

SHAMROCK AVE

Good

Over: DRAINAGE

093432702, Plymouth, IA

Built 1991 Load: 32.7 t ADT: 20

POLK AVE

Good

Over: WILLOW CREEK

093441102, Plymouth, IA

Built 2006 Load: 32.7 t ADT: 11

LOCAL

Good

Over: DRAINAGE

093441501, Plymouth, IA

Built 2005 Load: 32.7 t ADT: 5

POLK AVE

Good

Over: DRAINAGE

093443502, Plymouth, IA

Built 2005 Load: 32.7 t ADT: 11

KEY AVE

Good

Over: WEST BRANCH FLOYD RIVER

093450702, Plymouth, IA

Built 2008 Load: 32.7 t ADT: 34

MAHOGANY AVE

Good

Over: WOLF CREEK

093451502, Plymouth, IA

Built 2006 Load: 32.7 t ADT: 15

120TH ST

Good

Over: MINK CREEK

093461503, Plymouth, IA

Built 2003 Load: 32.7 t ADT: 26

FM

Good

Over: DRAINAGE

093481003, Plymouth, IA

Built 1964 Load: 32.7 t ADT: 240

540TH ST

Good

Over: S LIZARD CREEK DD 22

091331601, Pocahontas, IA

Built 2015 Load: 32.7 t ADT: 15

550TH ST

Good

Over: DD #22 SO LIZARD CK

091332201, Pocahontas, IA

Built 2018 Load: 32.7 t ADT: 34

210TH AVE

Good

Over: S LIZARD CREEK DD#22

091332502, Pocahontas, IA

Built 2023 Load: 32.7 t ADT: 11

100TH AVE

Good

Over: BR LITTLE CEDAR CREEK

091341802, Pocahontas, IA

Built 2021 Load: 32.7 t ADT: 5

200TH AVE

Good

Over: BR N LIZARD CREEK

092331402, Pocahontas, IA

Built 2015 Load: 32.7 t ADT: 15

490TH ST

Good

Over: LIZARD CREEK

092332201, Pocahontas, IA

Built 2012 Load: 32.7 t ADT: 26

LOCAL

Good

Over: DD #21

092333101, Pocahontas, IA

Built 1990 Load: 32.7 t ADT: 20

C 29 (480TH ST)

Good

Over: BIG CEDAR CK DD #41

092341401, Pocahontas, IA

Built 2011 Load: 32.7 t ADT: 230

450TH ST

Good

Over: LITTLE CEDAR CREEK

093343101, Pocahontas, IA

Built 2017 Load: 32.7 t ADT: 34

POLK CITY DRIVE

Good

Over: ROCK CREEK

080242113, Polk, IA

Built 2000 Load: 32.7 t ADT: 2,380

NE 62

Good

Over: SMALL STREAM

079230700, Polk, IA

Built 2003 Load: 32.7 t ADT: 6,038

FM

Good

Over: BRANCH FOUR MILE CREEK

079230800, Polk, IA

Built 2003 Load: 32.7 t ADT: 2,571

SE 37TH STREET

Good

Over: CREEK

079251600, Polk, IA

Built 2001 Load: 32.7 t ADT: 8,166

NW 18TH ST

Good

Over: ROCK CREEK

080241600, Polk, IA

Built 1982 Load: 32.7 t ADT: 1,649

FM

Good

Over: SKUNK RIVER OVFLW

081223006, Polk, IA

Built 1992 Load: 32.7 t ADT: 967

LOCAL ROAD

Good

Over: DRAINAGE DITCH

081232307, Polk, IA

Built 2000 Load: 32.7 t ADT: 11

LOCAL ROAD

Good

Over: OLD SKUNK R CHAN

081232401, Polk, IA

Built 1992 Load: 32.7 t ADT: 5

39TH ST

Good

Over: JORDAN CREEK

000000000, Polk, IA

Built 1974 Load: 32.7 t ADT: 2,565

50TH ST

Good

Over: JORDAN CREEK

000000000, Polk, IA

Built 2005 Load: 32.7 t ADT: 8,476

NETRILEIN DR

Good

Over: BR.FOUR MILE CREEK

080241300, Polk, IA

Built 1991 Load: 32.7 t ADT: 1,404

LINCOLN ST.

Good

Over: DRAINAGE DITCH

080223100, Polk, IA

Built 1996 Load: 32.7 t ADT: 1,190

NW 18TH STREET

Good

Over: ROCK CREEK

080241001, Polk, IA

Built 2003 Load: 32.7 t ADT: 5,613

SW STATE STREET

Good

Over: SAYLOR CREEK

080242700, Polk, IA

Built 1997 Load: 32.7 t ADT: 748

MLK JR PKWY E/W

Good

Over: RACCOON RIVER

078240801, Polk, IA

Built 2005 Load: 32.7 t ADT: 7,253

Showing 12,001-12,050 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.