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

FM

Good

Over: N.SKUNK RIVER OVERFLOW

077143304, Mahaska, IA

Built 1991 Load: 32.7 t ADT: 320

FM

Good

Over: DRAINAGE

075163204, Mahaska, IA

Built 2001 Load: 32.7 t ADT: 620

US 63

Good

Over: TRIB. TO MUCHAKINOCK

5.2 MILES N OF JCT IA 137, Mahaska, IA

Built 1997 Load: 32.7 t ADT: 6,250

FM

Good

Over: SMALL

074183505, Marion, IA

Built 1983 Load: 32.7 t ADT: 110

LOCAL

Good

Over: STREAM

074192903, Marion, IA

Built 2009 Load: 32.7 t ADT: 16

OREGON DR

Good

Over: SMALL STREAM

075192303, Marion, IA

Built 2004 Load: 32.7 t ADT: 51

LOCAL

Good

Over: STREAM

075201502, Marion, IA

Built 1994 Load: 32.7 t ADT: 15

198TH PLACE

Good

Over: SMALL STREAM

076182005, Marion, IA

Built 1992 Load: 32.7 t ADT: 1,120

FM

Good

Over: SM STREAM

076183303, Marion, IA

Built 2002 Load: 32.7 t ADT: 3,270

FM

Good

Over: SMALL STREAM

076183305, Marion, IA

Built 2002 Load: 32.7 t ADT: 3,270

T17

Good

Over: SMALL STREAM

076183405, Marion, IA

Built 1982 Load: 32.7 t ADT: 3,270

100TH AVE

Good

Over: STREAM

076201004, Marion, IA

Built 2018 Load: 32.7 t ADT: 26

FM

Good

Over: SMALL STREAM

75213300, Marion, IA

Built 2009 Load: 32.7 t ADT: 60

FM

Good

Over: SMALL

074183603, Marion, IA

Built 1983 Load: 32.7 t ADT: 110

IA 330

Good

Over: DRAINAGE DITCH

1.8 MI S OF N JCT SR S52, Marshall, IA

Built 1982 Load: 32.7 t ADT: 8,300

LOCAL

Good

Over: BRANCH S TIMBER CREEK

082181501, Marshall, IA

Built 2005 Load: 32.7 t ADT: 41

LOCAL

Good

Over: SNIPE CREEK

082182303, Marshall, IA

Built 2003 Load: 32.7 t ADT: 26

LOCAL

Good

Over: BR OF BURNETT CR

084181201, Marshall, IA

Built 2008 Load: 32.7 t ADT: 82

IA 330

Good

Over: STREAM

0.7 MILES N OF JCT SR E35, Marshall, IA

Built 1970 Load: 32.7 t ADT: 2,780

E29 190TH ST

Good

Over: MINERVA CREEK

084202001, Marshall, IA

Built 2001 Load: 32.7 t ADT: 383

LOCAL

Good

Over: CREEK

085180401, Marshall, IA

Built 1989 Load: 32.7 t ADT: 20

LOCAL

Good

Over: BR TIMBER CREEK

083182305, Marshall, IA

Built 1992 Load: 32.7 t ADT: 113

FM E-41

Good

Over: BR LINN CREEK

083190803, Marshall, IA

Built 1996 Load: 32.7 t ADT: 412

LOCAL

Good

Over: BR TIMBER CREEK

083202302, Marshall, IA

Built 1990 Load: 32.7 t ADT: 26

ARNEY AVE

Good

Over: MINERVA CREEK

085203102, Marshall, IA

Built 2000 Load: 32.7 t ADT: 15

LOCAL

Good

Over: STREAM

085191003, Marshall, IA

Built 2009 Load: 32.7 t ADT: 324

LOCAL

Good

Over: STREAM

083202802, Marshall, IA

Built 2009 Load: 32.7 t ADT: 20

N 13TH ST

Good

Over: STREAM

084182700, Marshall, IA

Built 2012 Load: 32.7 t ADT: 1,661

SUMMIT ST

Good

Over: STREAM

084182700, Marshall, IA

Built 2012 Load: 32.7 t ADT: 2,348

221ST STREET

Good

Over: PONY CREEK

073432204, Mills, IA

Built 1995 Load: 32.7 t ADT: 2,649

LCL-QUEEN AVE

Good

Over: HUNTERS BRANCH

071402601, Mills, IA

Built 1991 Load: 32.7 t ADT: 34

300TH ST

Good

Over: SPRING VALLEY CREEK

071413102, Mills, IA

Built 2010 Load: 32.7 t ADT: 26

FM-195TH ST

Good

Over: HAYNIE SLOUGH

071430806, Mills, IA

Built 1988 Load: 32.7 t ADT: 240

MASTERS RD

Good

Over: STREAM

072423111, Mills, IA

Built 2012 Load: 32.7 t ADT: 60

MONTAGUE RD

Good

Over: WAUBONSIE CR

072423304, Mills, IA

Built 2016 Load: 32.7 t ADT: 29

FA-370TH ST

Good

Over: STREAM

073402902, Mills, IA

Built 1992 Load: 32.7 t ADT: 210

FM-195TH ST

Good

Over: ST MARY'S DITCH

073430806, Mills, IA

Built 1995 Load: 32.7 t ADT: 1,247

I-29

Good

Over: FULSOM LAKE OUTLET

1.7 mi. N of N jct. US 34, Mills, IA

Built 2010 Load: 32.7 t ADT: 19,700

OLD IA 105

Good

Over: CEDAR RIVER

099181412, Mitchell, IA

Built 1989 Load: 32.7 t ADT: 746

VALLEY AVE

Good

Over: CREEK

097150302, Mitchell, IA

Built 2002 Load: 32.7 t ADT: 33

NOBLE AVE

Good

Over: CREEK

097161704, Mitchell, IA

Built 2001 Load: 32.7 t ADT: 70

319TH

Good

Over: CREEK

097161807, Mitchell, IA

Built 2003 Load: 32.7 t ADT: 108

316TH

Good

Over: ROCK CREEK

097171705, Mitchell, IA

Built 1990 Load: 32.7 t ADT: 59

340TH

Good

Over: ROCK CREEK

097180103, Mitchell, IA

Built 1977 Load: 32.7 t ADT: 44

UNDERWOOD AVE

Good

Over: SOAP CREEK

098150902, Mitchell, IA

Built 2005 Load: 32.7 t ADT: 33

NOBLE AVE

Good

Over: SPRING CREEK

098163202, Mitchell, IA

Built 2008 Load: 32.7 t ADT: 20

385TH

Good

Over: SUGAR CREEK

098171003, Mitchell, IA

Built 1998 Load: 32.7 t ADT: 285

ECHO AVE

Good

Over: CREEK

098183502, Mitchell, IA

Built 1998 Load: 32.7 t ADT: 33

LOCAL

Good

Over: WAPSIPINICON RIVER

099151501, Mitchell, IA

Built 2006 Load: 32.7 t ADT: 44

TIMBER AVE

Good

Over: BEAVER CREEK

099152902, Mitchell, IA

Built 2004 Load: 32.7 t ADT: 49

Showing 11,901-11,950 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.