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

Fair

Over: SMALL STREAM

076050606, Louisa, IA

Built 1980 Load: 32.7 t ADT: 20

FM

Fair

Over: SMALL

076050803, Louisa, IA

Built 1979 Load: 32.7 t ADT: 20

60TH ST

Fair

Over: SMALL STREAM

73040701, Louisa, IA

Built 2013 Load: 32.7 t ADT: 21

FM

Fair

Over: NORTH CEDAR CREEK

072202104, Lucas, IA

Built 1974 Load: 32.7 t ADT: 60

FM

Fair

Over: CARRUTHERS CREEK

073202103, Lucas, IA

Built 1995 Load: 32.7 t ADT: 20

FM

Fair

Over: BRANCH OF LONG BRANCH CK

073210401, Lucas, IA

Built 1984 Load: 32.7 t ADT: 50

FM

Fair

Over: STONY CREEK

073220802, Lucas, IA

Built 1980 Load: 32.7 t ADT: 35

LOCAL

Fair

Over: STREAM

098443302, Lyon, IA

Built 1981 Load: 32.7 t ADT: 41

FM

Fair

Over: SMALL STREAM

098452101, Lyon, IA

Built 1978 Load: 32.7 t ADT: 50

FM

Fair

Over: LIZARD CREEK

098463302, Lyon, IA

Built 1975 Load: 32.7 t ADT: 1,416

LOCAL

Fair

Over: PLUM CREEK

098481003, Lyon, IA

Built 1979 Load: 32.7 t ADT: 41

LOCAL

Fair

Over: PLUM CREEK

098481101, Lyon, IA

Built 1979 Load: 32.7 t ADT: 62

FM

Fair

Over: SMALL STREAM

099431901, Lyon, IA

Built 1975 Load: 32.7 t ADT: 190

FM

Fair

Over: SMALL STREAM

099461902, Lyon, IA

Built 2005 Load: 32.7 t ADT: 240

LOCAL ROAD

Fair

Over: PETERSON CREEK

099481701, Lyon, IA

Built 1991 Load: 32.7 t ADT: 15

I-80

Fair

Over: DRAINAGE DITCH

1.0 mi. W of Jct. SR P-53, Madison, IA

Built 1959 Load: 32.7 t ADT: 27,600

FM

Fair

Over: STREAM

074283507, Madison, IA

Built 1974 Load: 32.7 t ADT: 34

LOCAL

Fair

Over: STREAM

074283509, Madison, IA

Built 1974 Load: 32.7 t ADT: 5

FM

Fair

Over: DRAINAGE DITCH

074291302, Madison, IA

Built 1984 Load: 32.7 t ADT: 71

FM

Fair

Over: SMALL STREAM

075282107, Madison, IA

Built 1986 Load: 32.7 t ADT: 71

US 63

Fair

Over: NENEBEC CREEK

0.2 mi. N of Jct. SR G71, Mahaska, IA

Built 1998 Load: 32.7 t ADT: 12,500

US 63

Fair

Over: LITTLE MUCHAKINOCK CREEK

0.2 MILES NORTH OF IA 163, Mahaska, IA

Built 1963 Load: 32.7 t ADT: 6,500

LOCAL

Fair

Over: DRAINAGE

074162403, Mahaska, IA

Built 1987 Load: 32.7 t ADT: 710

LOCAL

Fair

Over: S COAL CREEK

074171906, Mahaska, IA

Built 2005 Load: 32.7 t ADT: 60

FM

Fair

Over: TURKEY RUN

074172101, Mahaska, IA

Built 1983 Load: 32.7 t ADT: 610

FM

Fair

Over: TURKEY RUN

074172301, Mahaska, IA

Built 1994 Load: 32.7 t ADT: 610

FM

Fair

Over: SOUTH SKUNK RIVER

075141504, Mahaska, IA

Built 1982 Load: 32.7 t ADT: 330

FM

Fair

Over: SNYDER CREEK

075142206, Mahaska, IA

Built 1982 Load: 32.7 t ADT: 330

LOCAL

Fair

Over: SPRING CREEK

075152102, Mahaska, IA

Built 1986 Load: 32.7 t ADT: 840

LOCAL

Fair

Over: DRAINAGE

076143305, Mahaska, IA

Built 1988 Load: 32.7 t ADT: 50

LOCAL

Fair

Over: MIDDLE CREEK

076143408, Mahaska, IA

Built 1982 Load: 32.7 t ADT: 26

FM

Fair

Over: E BR BUCKLEY CREEK

077171006, Mahaska, IA

Built 1983 Load: 32.7 t ADT: 1,130

LOCAL

Fair

Over: DES MOINES RIVER

074162201, Mahaska, IA

Built 1987 Load: 32.7 t ADT: 710

IA 163

Fair

Over: LITTLE MUCHIKINOCK CREEK

2.4 MI. E OF JCT. IA 92, Mahaska, IA

Built 1995 Load: 32.7 t ADT: 7,800

IA 163

Fair

Over: MUCHAKINOK CREEK

1.2 MILES E OF JCT SR G5T, Mahaska, IA

Built 1997 Load: 32.7 t ADT: 12,200

FM

Fair

Over: SMALL STREAM

074190402, Marion, IA

Built 1982 Load: 32.7 t ADT: 90

FM

Fair

Over: SMALL STREAM

074191908, Marion, IA

Built 1982 Load: 32.7 t ADT: 70

168TH PLACE

Fair

Over: STREAM

074192706, Marion, IA

Built 2018 Load: 32.7 t ADT: 34

G76

Fair

Over: SMALL STREAM

074202401, Marion, IA

Built 1996 Load: 32.7 t ADT: 400

FM

Fair

Over: VAN ZANTE CREEK

077180504, Marion, IA

Built 1982 Load: 32.7 t ADT: 40

FM

Fair

Over: VAN ZANTE CREEK

077191202, Marion, IA

Built 1982 Load: 32.7 t ADT: 100

LOCAL

Fair

Over: STREAM

077192804, Marion, IA

Built 1995 Load: 32.7 t ADT: 113

FM

Fair

Over: MINERVA CREEK

084190504, Marshall, IA

Built 1981 Load: 32.7 t ADT: 255

FM

Fair

Over: SMALL CREEK

084192101, Marshall, IA

Built 1985 Load: 32.7 t ADT: 746

FM

Fair

Over: SMALL STREAM

084202602, Marshall, IA

Built 1985 Load: 32.7 t ADT: 619

FM

Fair

Over: SMALL STREAM

084203404, Marshall, IA

Built 1984 Load: 32.7 t ADT: 737

LOCUST STREET

Fair

Over: TINKLE BRANCH

000000000, Mills, IA

Built 1976 Load: 32.7 t ADT: 8,957

SHARP STREET

Fair

Over: SMALL STREAM

000000000, Mills, IA

Built 1960 Load: 32.7 t ADT: 3,979

284TH STREET

Fair

Over: SILVER CREEK BRANCH

072420202, Mills, IA

Built 1959 Load: 32.7 t ADT: 568

LCL-RAINS AVE

Fair

Over: DRAINAGE

071413501, Mills, IA

Built 1964 Load: 32.7 t ADT: 11

Showing 6,751-6,800 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.