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: ROCK CREEK

097172402, Floyd, IA

Built 1996 Load: 36.9 t ADT: 1,365

FM

Fair

Over: CREEK

089152301, Grundy, IA

Built 1966 Load: 36.9 t ADT: 707

FM 2030 170TH

Fair

Over: DRAINAGE DITCH #9

095233201, Hancock, IA

Built 1975 Load: 36.9 t ADT: 688

1840 170TH ST

Fair

Over: E BR IOWA RIVER

095243601, Hancock, IA

Built 1975 Load: 36.9 t ADT: 649

FM

Fair

Over: S FORK CLANTON CREEK

074271506, Madison, IA

Built 1977 Load: 36.9 t ADT: 89

FM

Fair

Over: OTTER CREEK

099411901, Osceola, IA

Built 1975 Load: 36.9 t ADT: 199

IA 3

Fair

Over: WESTFIELD CREEK

0.2 mi. W of W jct. IA 12, Plymouth, IA

Built 1962 Load: 36.9 t ADT: 1,570

IA 3

Fair

Over: BROKEN KETTLE CREEK

2.3 mi. W of SR K22, Plymouth, IA

Built 1975 Load: 36.9 t ADT: 940

US 6

Fair

Over: STREAM

2.0 MI. E. OF Jct. SR L66, Pottawattamie, IA

Built 1997 Load: 36.9 t ADT: 2,770

450TH STREET

Fair

Over: FARM CREEK

074392202, Pottawattamie, IA

Built 1979 Load: 36.9 t ADT: 26

FM-JUNIPER ROAD

Fair

Over: WALNUT CREEK

076383401, Pottawattamie, IA

Built 1997 Load: 36.9 t ADT: 26

10TH ST

Fair

Over: BIG SIOUX RIVER

000000000, Sioux, IA

Built 1980 Load: 36.9 t ADT: 670

IA 31

Fair

Over: STREAM

3.1 mi. S of SR D22, Woodbury, IA

Built 1956 Load: 36.9 t ADT: 1,070

IA 21

Fair

Over: STEIN CREEK

200 ft. N of Jct. SR E36, Benton, IA

Built 1979 Load: 37.0 t ADT: 1,470

HUDSON RD

Fair

Over: DRAINAGE DITCH

000000000, Black Hawk, IA

Built 1978 Load: 37.0 t ADT: 4,985

190TH ST

Fair

Over: STREAM

092142301, Bremer, IA

Built 1945 Load: 37.0 t ADT: 1,041

IA 64 & 136

Fair

Over: LITTLE BEAR CREEK

0.2 mi. E of W Jct IA 136, Jones, IA

Built 1978 Load: 37.0 t ADT: 2,470

IA 140

Fair

Over: CLEAR CREEK

2.8 mi. S of IA 3, Plymouth, IA

Built 1964 Load: 37.0 t ADT: 1,130

28TH AVE

Fair

Over: INDIAN CREEK

000000000, Pottawattamie, IA

Built 1983 Load: 37.0 t ADT: 170

23RD AVE

Fair

Over: INDIAN CREEK

000000000, Pottawattamie, IA

Built 1980 Load: 37.0 t ADT: 7,347

LOCAL

Fair

Over: JACKSON CREEK

068211104, Wayne, IA

Built 1993 Load: 37.0 t ADT: 11

FM

Fair

Over: MAPLE RIVER

086422708, Woodbury, IA

Built 1985 Load: 37.0 t ADT: 429

LOCAL

Fair

Over: BR PRAIRIE CK

082110802, Benton, IA

Built 1989 Load: 37.1 t ADT: 40

LOCAL

Fair

Over: BUCKEYE CREEK

082120901, Benton, IA

Built 1989 Load: 37.1 t ADT: 40

LOCAL

Fair

Over: STEIN CREEK

084120601, Benton, IA

Built 1990 Load: 37.1 t ADT: 34

LOCAL

Fair

Over: PRAIRIE CK

086091901, Benton, IA

Built 1989 Load: 37.1 t ADT: 26

COUNTY ROAD

Fair

Over: PANTHER CREEK

079280801, Dallas, IA

Built 1988 Load: 37.1 t ADT: 21

FM

Fair

Over: N. BRANCH NORTH RIVER

077272804, Madison, IA

Built 1985 Load: 37.1 t ADT: 50

LIME KILN RD

Fair

Over: BIG CEDAR RIVER

098173403, Mitchell, IA

Built 1992 Load: 37.1 t ADT: 167

LOCAL

Fair

Over: MILLER CREEK

073173604, Monroe, IA

Built 1989 Load: 37.1 t ADT: 60

160TH STREET

Fair

Over: E TARKIO RIVER

069370609, Page, IA

Built 1986 Load: 37.1 t ADT: 45

LOCAL

Fair

Over: CYLINDER CREEK

096313101, Palo Alto, IA

Built 1991 Load: 37.1 t ADT: 81

IA 4

Fair

Over: NORTH LIZARD CREEK

5.6 mi. N of IA 3, Pocahontas, IA

Built 1976 Load: 37.1 t ADT: 3,150

SB I-29

Fair

Over: OVER CC RR

2.1 MI. N OF JCT. 6, Pottawattamie, IA

Built 1968 Load: 37.1 t ADT: 5,800

LOCAL

Fair

Over: CROOKED CREEK

070293102, Ringgold, IA

Built 1952 Load: 37.1 t ADT: 5

FM

Fair

Over: INLET BLACKHAWK LK

086360903, Sac, IA

Built 1989 Load: 37.1 t ADT: 330

FM

Fair

Over: SOUTH RIVER

074251704, Warren, IA

Built 1986 Load: 37.1 t ADT: 100

BEARDSLEY STREET

Fair

Over: SM STREAM

077251200, Warren, IA

Built 1989 Load: 37.1 t ADT: 616

LOCAL

Fair

Over: DD# 219

092250601, Wright, IA

Built 1987 Load: 37.1 t ADT: 21

LOCAL

Fair

Over: STREAM

075302801, Adair, IA

Built 2005 Load: 37.2 t ADT: 35

IA 3

Fair

Over: LITTLE MAQUOKETA RIVER

0.4 mi. N of N Jct SR D10, Dubuque, IA

Built 1947 Load: 37.2 t ADT: 5,100

FM

Fair

Over: LYTLE CREEK

087E22903, Dubuque, IA

Built 1992 Load: 37.2 t ADT: 260

FM

Fair

Over: WOLF CREEK, BRANCH

086182401, Grundy, IA

Built 1989 Load: 37.2 t ADT: 59

FM

Fair

Over: BUCK CREEK

089252303, Hamilton, IA

Built 1975 Load: 37.2 t ADT: 240

COUNTY RD X-64

Fair

Over: MILL CREEK

083012813, Jones, IA

Built 1957 Load: 37.2 t ADT: 432

LOCAL RD

Fair

Over: S FORK CLANTON CREEK

074273304, Madison, IA

Built 1989 Load: 37.2 t ADT: 34

LOCAL

Fair

Over: WALNUT CREEK

075182204, Marion, IA

Built 1988 Load: 37.2 t ADT: 82

400TH

Fair

Over: BURR OAK CREEK

098160501, Mitchell, IA

Built 1975 Load: 37.2 t ADT: 59

450TH

Fair

Over: SMALL STREAM

099161101, Mitchell, IA

Built 1974 Load: 37.2 t ADT: 26

100TH ST

Fair

Over: DRAINAGE

073360605, Montgomery, IA

Built 1990 Load: 37.2 t ADT: 20

Showing 7,851-7,900 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.