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: DRAINAGE

077172004, Mahaska, IA

Built 1955 Load: 15.7 t ADT: 20

LOCAL

Fair

Over: DRAINAGE

077173609, Mahaska, IA

Built 1955 Load: 15.7 t ADT: 50

LOCAL

Fair

Over: STREAM

074190104, Marion, IA

Built 1960 Load: 15.7 t ADT: 145

FM

Fair

Over: ELK CREEK

082432405, Monona, IA

Built 1955 Load: 15.7 t ADT: 40

FM

Fair

Over: MOFFAT BRANCH

071182006, Monroe, IA

Built 1950 Load: 15.7 t ADT: 80

FM

Fair

Over: STREAM

071191103, Monroe, IA

Built 1959 Load: 15.7 t ADT: 140

LOCAL

Fair

Over: OCHEYDAN RIVER

098392001, Osceola, IA

Built 1954 Load: 15.7 t ADT: 21

270TH STREET

Fair

Over: WEST MILL CREEK

067370501, Page, IA

Built 1957 Load: 15.7 t ADT: 26

290TH STREET

Fair

Over: WEST MILL CREEK

067381301, Page, IA

Built 1957 Load: 15.7 t ADT: 79

170TH STREET

Fair

Over: EAST TARKIO CREEK

069370701, Page, IA

Built 1956 Load: 15.7 t ADT: 26

FM-IDELWOOD RD

Fair

Over: KEG CREEK

075420101, Pottawattamie, IA

Built 1958 Load: 15.7 t ADT: 45

FM-152ND STREET

Fair

Over: HONEY CREEK

077443404, Pottawattamie, IA

Built 1959 Load: 15.7 t ADT: 100

FM

Fair

Over: E FORK GRAND RIVER

069291301, Ringgold, IA

Built 1957 Load: 15.7 t ADT: 50

LOCAL

Fair

Over: CROOKED CREEK

069303205, Ringgold, IA

Built 1957 Load: 15.7 t ADT: 50

FM

Fair

Over: PLATTE RIVER

070312101, Ringgold, IA

Built 1961 Load: 15.7 t ADT: 29

LOCAL

Fair

Over: MIDDLE RIVER

074332603, Adair, IA

Built 1920 Load: 15.8 t ADT: 30

LOCAL

Fair

Over: LONG CREEK

069260503, Decatur, IA

Built 1984 Load: 15.8 t ADT: 21

240 AVENUE

Fair

Over: COOPER CREEK

068431202, Fremont, IA

Built 1990 Load: 15.8 t ADT: 5

LOCAL

Fair

Over: HONEY CREEK

087222501, Hardin, IA

Built 1983 Load: 15.8 t ADT: 15

TEAKWOOD ROAD

Fair

Over: POTATO CREEK

077432401, Pottawattamie, IA

Built 1946 Load: 15.8 t ADT: 45

FM

Fair

Over: SMALL STREAM

086370802, Sac, IA

Built 1930 Load: 15.8 t ADT: 50

US 18

Fair

Over: DRAINAGE DITCH

0.1 mi E of SR K18, Sioux, IA

Built 1944 Load: 15.8 t ADT: 3,040

ORANGE AVENUE

Fair

Over: KEMP CREEK

073332702, Adams, IA

Built 1956 Load: 15.9 t ADT: 15

LOCAL

Fair

Over: SMALL STREAM

099052210, Allamakee, IA

Built 1975 Load: 15.9 t ADT: 26

FM

Fair

Over: FIELD STREAM

084342302, Carroll, IA

Built 1964 Load: 15.9 t ADT: 687

FM

Fair

Over: SUGAR CR

079023401, Cedar, IA

Built 1945 Load: 15.9 t ADT: 90

LOCL MIDDLE RD

Fair

Over: MILL CREEK

093403004, Cherokee, IA

Built 1964 Load: 15.9 t ADT: 30

290TH ST

Fair

Over: COON CREEK

092050701, Clayton, IA

Built 1920 Load: 15.9 t ADT: 82

LOCAL 120 AVE

Fair

Over: BUFFALO CREEK OVERFLOW

087062804, Delaware, IA

Built 2003 Load: 15.9 t ADT: 44

LOCAL

Fair

Over: W FORK DES MOINES RIVER

098332903, Emmet, IA

Built 1959 Load: 15.9 t ADT: 34

LOCAL

Fair

Over: BRANCH BLACKHAWK CREEK

088171202, Grundy, IA

Built 1957 Load: 15.9 t ADT: 26

LOCAL

Fair

Over: BRANCH BEAVER CREEK

089160401, Grundy, IA

Built 1955 Load: 15.9 t ADT: 20

LOCAL

Fair

Over: BRANCH BLACKHAWK CREEK

089163601, Grundy, IA

Built 1956 Load: 15.9 t ADT: 20

FM

Fair

Over: BEAR CREEK

087193502, Hardin, IA

Built 1986 Load: 15.9 t ADT: 20

FM

Fair

Over: S FORK MAQUOKETA RIVER

085E11905, Jackson, IA

Built 1954 Load: 15.9 t ADT: 510

FM

Fair

Over: LUX CREEK

087E40707, Jackson, IA

Built 1961 Load: 15.9 t ADT: 430

FM

Fair

Over: DEVIL CREEK

068053004, Lee, IA

Built 1944 Load: 15.9 t ADT: 45

DUROW RD

Fair

Over: BLUE CREEK

086083105, Linn, IA

Built 1951 Load: 15.9 t ADT: 148

LOCAL

Fair

Over: ST JOSEPHS CREEK

074160605, Mahaska, IA

Built 1953 Load: 15.9 t ADT: 80

LOCAL

Fair

Over: S COAL CREEK

074171112, Mahaska, IA

Built 1959 Load: 15.9 t ADT: 40

FM

Fair

Over: TURKEY RUN

074171506, Mahaska, IA

Built 1952 Load: 15.9 t ADT: 35

FM

Fair

Over: S COAL CREEK

074172004, Mahaska, IA

Built 1954 Load: 15.9 t ADT: 100

FM

Fair

Over: MIDDLE CREEK

077162202, Mahaska, IA

Built 1963 Load: 15.9 t ADT: 25

LOCAL

Fair

Over: STREAM

074212404, Marion, IA

Built 1960 Load: 15.9 t ADT: 62

FM

Fair

Over: STREAM

085442212, Monona, IA

Built 1956 Load: 15.9 t ADT: 71

FM

Fair

Over: CREEK

071182705, Monroe, IA

Built 1959 Load: 15.9 t ADT: 20

LOCAL ROAD

Fair

Over: WALNUT CREEK

073380401, Montgomery, IA

Built 1967 Load: 15.9 t ADT: 26

FM

Fair

Over: BIG CEDAR CK DD #41

091330702, Pocahontas, IA

Built 1959 Load: 15.9 t ADT: 60

310TH ST

Fair

Over: BALLARD CREEK

082242001, Story, IA

Built 1970 Load: 15.9 t ADT: 50

FM

Fair

Over: LITTLE WOLF CREEK

086160704, Tama, IA

Built 1955 Load: 15.9 t ADT: 49

Showing 1,551-1,600 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.