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

Fair

Over: BADGER CREEK

077261604, Madison, IA

Built 1994 Load: 30.7 t ADT: 79

FM

Fair

Over: OVER UP RR

074211407, Marion, IA

Built 1961 Load: 30.7 t ADT: 1,100

LOCAL

Fair

Over: LITTLE ASHER CREEK

085182201, Marshall, IA

Built 1980 Load: 30.7 t ADT: 47

257TH ST

Fair

Over: CREEK

079E50507, Scott, IA

Built 1956 Load: 30.7 t ADT: 940

US 218

Fair

Over: STREAM

1.8 MI. S 0F JCT IA 22, Washington, IA

Built 1984 Load: 30.7 t ADT: 14,900

FM

Fair

Over: KRUMM CREEK

096101302, Winneshiek, IA

Built 1981 Load: 30.7 t ADT: 206

FM

Fair

Over: YELLOW RIVER

096052406, Allamakee, IA

Built 1970 Load: 30.8 t ADT: 933

LOCAL

Fair

Over: STREAM

068170205, Appanoose, IA

Built 1979 Load: 30.8 t ADT: 41

LOCAL

Fair

Over: PRAIRIE CREEK

083121303, Benton, IA

Built 1986 Load: 30.8 t ADT: 79

FM

Fair

Over: ROCK CREEK

085120501, Benton, IA

Built 1987 Load: 30.8 t ADT: 20

LOCAL

Fair

Over: BIG CREEK

082250401, Boone, IA

Built 1978 Load: 30.8 t ADT: 26

FM

Fair

Over: SMALL STREAM

089093606, Buchanan, IA

Built 1966 Load: 30.8 t ADT: 167

LOCAL

Fair

Over: RACCOON RIVER

090360101, Buena Vista, IA

Built 1973 Load: 30.8 t ADT: 26

LOCAL

Fair

Over: BROOKS CREEK

092381301, Buena Vista, IA

Built 1978 Load: 30.8 t ADT: 40

FM

Fair

Over: HOWARD CREEK

094052406, Clayton, IA

Built 1983 Load: 30.8 t ADT: 344

FM

Fair

Over: CREEK

080271103, Dallas, IA

Built 1969 Load: 30.8 t ADT: 399

FM

Fair

Over: SOAP CREEK

070152406, Davis, IA

Built 1973 Load: 30.8 t ADT: 80

LOCAL

Fair

Over: HAWKEYE CREEK

072021502, Des Moines, IA

Built 1966 Load: 30.8 t ADT: 62

LOCAL

Fair

Over: CREEK

095160304, Floyd, IA

Built 1984 Load: 30.8 t ADT: 78

FM S13

Fair

Over: IOWA RIVER

091223103, Franklin, IA

Built 1978 Load: 30.8 t ADT: 570

MEADOW AVE

Fair

Over: SMALL STREAM

083301806, Greene, IA

Built 1980 Load: 30.8 t ADT: 15

FM

Fair

Over: FORK OF MINNEHAHA CREEK

087160704, Grundy, IA

Built 1986 Load: 30.8 t ADT: 324

LOCAL ROAD

Fair

Over: BRANCH BLACKHAWK CRK

088173202, Grundy, IA

Built 1976 Load: 30.8 t ADT: 49

FM

Fair

Over: BLACK HAWK

088173503, Grundy, IA

Built 1981 Load: 30.8 t ADT: 79

FM

Fair

Over: BRANCH SPRING CREEK

078310906, Guthrie, IA

Built 1986 Load: 30.8 t ADT: 45

FM

Fair

Over: MASON CREEK

079322604, Guthrie, IA

Built 1987 Load: 30.8 t ADT: 50

FM

Fair

Over: IOWA RIVER

086190907, Hardin, IA

Built 1978 Load: 30.8 t ADT: 59

FM

Fair

Over: CREEK

089211105, Hardin, IA

Built 1982 Load: 30.8 t ADT: 442

FM

Fair

Over: DRAINAGE DITCH

091282702, Humboldt, IA

Built 1970 Load: 30.8 t ADT: 1,257

FM

Fair

Over: DD NO 100

093270301, Humboldt, IA

Built 1974 Load: 30.8 t ADT: 290

FM

Fair

Over: PRAIRIE CREEK

093272301, Humboldt, IA

Built 1970 Load: 30.8 t ADT: 71

FM

Fair

Over: EAST FORK BATTLE CREEK

088413603, Ida, IA

Built 1985 Load: 30.8 t ADT: 80

LOCAL

Fair

Over: MIDDLE ENGLISH R

078122302, Iowa, IA

Built 1976 Load: 30.8 t ADT: 50

LOCAL

Fair

Over: CREEK

085E50804, Jackson, IA

Built 1969 Load: 30.8 t ADT: 40

500TH ST SE

Fair

Over: STREAM

078051403, Johnson, IA

Built 1969 Load: 30.8 t ADT: 35

500TH ST

Fair

Over: STREAM

078051702, Johnson, IA

Built 1966 Load: 30.8 t ADT: 133

FM 540TH ST

Fair

Over: STREAM

078052001, Johnson, IA

Built 1955 Load: 30.8 t ADT: 880

NAPOLEON ST

Fair

Over: STREAM

078060203, Johnson, IA

Built 1972 Load: 30.8 t ADT: 388

SW OBSRVTRY AVE

Fair

Over: STREAM

078063306, Johnson, IA

Built 1973 Load: 30.8 t ADT: 72

SW JAMES AVE

Fair

Over: STREAM

078071502, Johnson, IA

Built 1960 Load: 30.8 t ADT: 41

LOCAL

Fair

Over: STREAM

078082102, Johnson, IA

Built 1966 Load: 30.8 t ADT: 61

FM

Fair

Over: STREAM

074111503, Keokuk, IA

Built 1973 Load: 30.8 t ADT: 80

INK ROAD

Fair

Over: TRIB TO ABBE CREEK

082050306, Linn, IA

Built 1987 Load: 30.8 t ADT: 128

COTTAGE GR.PWY

Fair

Over: WANATEE CREEK

083062101, Linn, IA

Built 1984 Load: 30.8 t ADT: 864

LOCAL

Fair

Over: SMALL STREAM

074051604, Louisa, IA

Built 1983 Load: 30.8 t ADT: 51

LOCAL

Fair

Over: MUSCATINE SLOUGH

075032405, Louisa, IA

Built 1981 Load: 30.8 t ADT: 41

LOCAL

Fair

Over: SMALL STREAM

075041501, Louisa, IA

Built 1966 Load: 30.8 t ADT: 82

LOCAL

Fair

Over: INDIAN CREEK

075042503, Louisa, IA

Built 1982 Load: 30.8 t ADT: 51

LOCAL

Fair

Over: SHORT CREEK

075050602, Louisa, IA

Built 1969 Load: 30.8 t ADT: 30

FM

Fair

Over: BR OF CHARITON RIVER

071201902, Lucas, IA

Built 1970 Load: 30.8 t ADT: 50

Showing 5,851-5,900 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.