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: BRLIZARDCK DD #53BR#19

091320606, Pocahontas, IA

Built 1966 Load: 26.8 t ADT: 409

FM

Fair

Over: SPRING CREEK

079223202, Polk, IA

Built 1990 Load: 26.8 t ADT: 3,924

PIONEER TRAIL

Fair

Over: SILVER CREEK

074412801, Pottawattamie, IA

Built 1948 Load: 26.8 t ADT: 71

FM-430TH STREET

Fair

Over: STREAM

077393202, Pottawattamie, IA

Built 1972 Load: 26.8 t ADT: 60

LOCAL

Fair

Over: FLOYD RIVER

094442803, Sioux, IA

Built 1966 Load: 26.8 t ADT: 26

IA 25

Fair

Over: SUMMIT LAKE

2.6 MI. N OF N JCT. US 34, Union, IA

Built 1976 Load: 26.8 t ADT: 1,950

MARTHA ST

Fair

Over: BACON CREEK

000000000, Woodbury, IA

Built 1994 Load: 26.8 t ADT: 3,223

LOCAL

Fair

Over: EAGLE CREEK

090250701, Wright, IA

Built 1968 Load: 26.8 t ADT: 35

LOCAL

Fair

Over: BRANCH OF NODAWAY RIVER

077333507, Adair, IA

Built 1949 Load: 26.9 t ADT: 11

LOCAL RD

Fair

Over: SUTTLE CREEK

096043006, Allamakee, IA

Built 1996 Load: 26.9 t ADT: 70

FM

Fair

Over: CREEK

080343501, Audubon, IA

Built 1936 Load: 26.9 t ADT: 11

FM

Fair

Over: CREEK

081342402, Audubon, IA

Built 1932 Load: 26.9 t ADT: 5

FM 260TH ST

Fair

Over: BASKINS CREEK

091132903, Bremer, IA

Built 1976 Load: 26.9 t ADT: 187

CONRAD LANE

Fair

Over: WHITEWATER CREEK

088012603, Dubuque, IA

Built 2022 Load: 26.9 t ADT: 11

200 AVENUE

Fair

Over: PLUM CREEK

069430402, Fremont, IA

Built 1978 Load: 26.9 t ADT: 51

SB I-29

Fair

Over: BURCHAM CREEK

1.2 MI. S OF JCT. IA 127, Harrison, IA

Built 1967 Load: 26.9 t ADT: 7,600

270TH ST

Fair

Over: SPRING CREEK

079413501, Harrison, IA

Built 1951 Load: 26.9 t ADT: 20

200TH ST

Fair

Over: LITTLE TURKEY RIVER

097121303, Howard, IA

Built 1992 Load: 26.9 t ADT: 51

182 AVE

Fair

Over: DRAINAGE DITCH

084E21204, Jackson, IA

Built 1999 Load: 26.9 t ADT: 540

COUNTY RD. E-17

Fair

Over: BRANCH KITTY CREEK

085021705, Jones, IA

Built 1997 Load: 26.9 t ADT: 88

FM

Fair

Over: WHITE BREAST CREEK

073221406, Lucas, IA

Built 1970 Load: 26.9 t ADT: 400

FM

Fair

Over: WALNUT CREEK

075182004, Marion, IA

Built 1987 Load: 26.9 t ADT: 1,280

LOCAL

Fair

Over: STREAM

071160603, Monroe, IA

Built 1968 Load: 26.9 t ADT: 20

M-60 / M AVE

Fair

Over: STREAM

069373204, Page, IA

Built 1962 Load: 26.9 t ADT: 210

FM

Fair

Over: LITTLE CEDAR CK DD #181

091340802, Pocahontas, IA

Built 1966 Load: 26.9 t ADT: 20

FM

Fair

Over: LITTLE SILVER CREEK

078400307, Shelby, IA

Built 1950 Load: 26.9 t ADT: 131

LOCAL

Fair

Over: LONG BRANCH CREEK

081372402, Shelby, IA

Built 1998 Load: 26.9 t ADT: 30

IA 10

Fair

Over: ORANGE CITY SLOUGH

4.5 mi. E of US 75, Sioux, IA

Built 1977 Load: 26.9 t ADT: 4,060

FM

Fair

Over: WEST BRANCH

096443001, Sioux, IA

Built 1963 Load: 26.9 t ADT: 738

610TH AVE

Fair

Over: BEAR CREEK

085230102, Story, IA

Built 1975 Load: 26.9 t ADT: 40

LOCAL

Fair

Over: EAST BRANCH SALT CREEK

084131501, Tama, IA

Built 1992 Load: 26.9 t ADT: 20

LOCAL

Fair

Over: COON CREEK

085141404, Tama, IA

Built 1997 Load: 26.9 t ADT: 137

IA 24

Fair

Over: GODDARD CREEK

1.8 mi. W of Jct. SR W14, Winneshiek, IA

Built 1932 Load: 26.9 t ADT: 2,250

FM

Fair

Over: YELLOW RIVER

096091505, Winneshiek, IA

Built 1964 Load: 26.9 t ADT: 491

SCENIC RIVER RD

Fair

Over: CREEK

099083004, Winneshiek, IA

Built 1900 Load: 26.9 t ADT: 44

LOCAL

Fair

Over: STREAM

089443502, Woodbury, IA

Built 1999 Load: 26.9 t ADT: 71

DOGWOOD

Fair

Over: STREAM

099221002, Worth, IA

Built 1961 Load: 26.9 t ADT: 29

LOCAL

Fair

Over: SMALL STREAM

092232301, Wright, IA

Built 1985 Load: 26.9 t ADT: 11

LOCAL RD

Fair

Over: NINE MILE CREEK

075330404, Adair, IA

Built 1971 Load: 27.0 t ADT: 51

E REINBECK RD

Fair

Over: TRIB TO MILLER CREEK

87-13-25-01-10, Black Hawk, IA

Built 1947 Load: 27.0 t ADT: 10

FM- W AVE

Fair

Over: LITTLE MAPLE RIVER

090393501, Cherokee, IA

Built 1971 Load: 27.0 t ADT: 290

LOCAL

Fair

Over: STREAM

076110303, Keokuk, IA

Built 1941 Load: 27.0 t ADT: 11

FM

Fair

Over: BURR OAK CREEK

098453502, Lyon, IA

Built 1961 Load: 27.0 t ADT: 758

FM

Fair

Over: CREEK

092433401, Plymouth, IA

Built 1976 Load: 27.0 t ADT: 848

LOCAL

Fair

Over: STREAM

068280501, Ringgold, IA

Built 1941 Load: 27.0 t ADT: 15

LOCAL (LWC)

Fair

Over: PRAIRIE CREEK

083113001, Benton, IA

Built 1986 Load: 27.1 t ADT: 45

FM

Fair

Over: WOLF CREEK

086120203, Benton, IA

Built 1967 Load: 27.1 t ADT: 100

N RAYMOND RD

Fair

Over: TRIB TO ELK RUN CREEK

89-12-13-02-10, Black Hawk, IA

Built 1973 Load: 27.1 t ADT: 2,259

IA 7

Fair

Over: OVER CC RR

0.8 mi. E of SR P19, Calhoun, IA

Built 1974 Load: 27.1 t ADT: 2,560

US 6

Fair

Over: TURKEY CREEK

3.7 MI. E OF JCT. IA #48, Cass, IA

Built 1959 Load: 27.1 t ADT: 1,960

Showing 4,751-4,800 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.