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: MUDDY CREEK

099352701, Dickinson, IA

Built 1962 Load: 26.5 t ADT: 26

LOCAL

Fair

Over: JACK CR

098323302, Emmet, IA

Built 1960 Load: 26.5 t ADT: 34

NETTLE AVE

Fair

Over: BUFFALO CREEK

092200502, Franklin, IA

Built 1983 Load: 26.5 t ADT: 20

QUAIL AVE

Fair

Over: OTTER CR

092201402, Franklin, IA

Built 1966 Load: 26.5 t ADT: 62

FM JONQUIL AVE

Fair

Over: OTTER CREEK

093211002, Franklin, IA

Built 1980 Load: 26.5 t ADT: 44

LARK AVE

Fair

Over: OTTER CREEK

093211202, Franklin, IA

Built 1981 Load: 26.5 t ADT: 47

FM

Fair

Over: SLIPPERY ELM HOLLOW CRK

068421304, Fremont, IA

Built 1985 Load: 26.5 t ADT: 40

NB I-29

Fair

Over: LITTLE SIOUX RIVER

0.4 MI. N OF JCT. SR F-20, Harrison, IA

Built 1967 Load: 26.5 t ADT: 7,250

SB I-29

Fair

Over: LITTLE SIOUX RIVER

0.4 MI. N OF JCT. SR F-20, Harrison, IA

Built 1967 Load: 26.5 t ADT: 7,250

HALFMOON AVE

Fair

Over: BUFFALO CREEK

080072908, Johnson, IA

Built 1976 Load: 26.5 t ADT: 112

LOCAL ROAD

Fair

Over: ALBERTSON CREEK

098472302, Lyon, IA

Built 2008 Load: 26.5 t ADT: 41

LOCAL

Fair

Over: HOWERDON CREEK

076292102, Madison, IA

Built 1987 Load: 26.5 t ADT: 20

FA-GASTON AVE

Fair

Over: STREAM

072420501, Mills, IA

Built 1960 Load: 26.5 t ADT: 678

500TH STREET

Fair

Over: OVER IAIS RR

076380402, Pottawattamie, IA

Built 1950 Load: 26.5 t ADT: 40

LOCAL

Fair

Over: STREAM

068311304, Ringgold, IA

Built 1996 Load: 26.5 t ADT: 11

WB US 30

Fair

Over: BIKE PATH & TRAIL

1.1 MI WEST OF JCT US 69, Story, IA

Built 1971 Load: 26.5 t ADT: 13,950

LOCAL

Fair

Over: ROCK CREEK

071121109, Wapello, IA

Built 1966 Load: 26.5 t ADT: 35

LOCAL

Fair

Over: SOUTH AVERY CREEK

072152002, Wapello, IA

Built 1970 Load: 26.5 t ADT: 30

LOCAL

Fair

Over: EAGLE CREEK

090250504, Wright, IA

Built 1985 Load: 26.5 t ADT: 30

P28 STUART ST

Fair

Over: CREEK

077300906, Adair, IA

Built 1977 Load: 26.6 t ADT: 1,295

LOCAL

Fair

Over: PAINT CREEK

097050408, Allamakee, IA

Built 1961 Load: 26.6 t ADT: 78

X20

Fair

Over: SMALL

099050209, Allamakee, IA

Built 2004 Load: 26.6 t ADT: 690

LOCAL

Fair

Over: CREEK

080360703, Audubon, IA

Built 1938 Load: 26.6 t ADT: 30

LOCAL

Fair

Over: STREAM

083090702, Benton, IA

Built 1977 Load: 26.6 t ADT: 39

LOCAL

Fair

Over: BR PRAIRIE CK

083110702, Benton, IA

Built 1985 Load: 26.6 t ADT: 26

110TH ST

Fair

Over: SMALL

093141001, Bremer, IA

Built 2009 Load: 26.6 t ADT: 33

BUTLER AV

Fair

Over: CREEK

093141802, Bremer, IA

Built 1996 Load: 26.6 t ADT: 15

LOCAL

Fair

Over: SMALL STREAM

089092104, Buchanan, IA

Built 1969 Load: 26.6 t ADT: 73

FM

Fair

Over: HARTER CREEK

089092701, Buchanan, IA

Built 1964 Load: 26.6 t ADT: 825

FM 140TH ST

Fair

Over: HUNTER CREEK

090092901, Buchanan, IA

Built 1968 Load: 26.6 t ADT: 108

EB US 20

Fair

Over: WAPSIPINICON RIVER

1.5 MI. E OF JCT. IA #150, Buchanan, IA

Built 1978 Load: 26.6 t ADT: 4,150

LOCAL

Fair

Over: BR MAPLE RIVER

091380602, Buena Vista, IA

Built 1973 Load: 26.6 t ADT: 71

T64

Fair

Over: SMALL STREAM

093150602, Butler, IA

Built 1968 Load: 26.6 t ADT: 776

FM

Fair

Over: BRUSHY FORK CREEK

083350804, Carroll, IA

Built 1968 Load: 26.6 t ADT: 638

LOCAL - 540TH

Fair

Over: WATERWAY

074370706, Cass, IA

Built 1977 Load: 26.6 t ADT: 50

FM 450TH ST

Fair

Over: BEAR CREEK

093412401, Cherokee, IA

Built 1966 Load: 26.6 t ADT: 319

FM 190TH AVE

Fair

Over: PRAIRIE CREEK

096373402, Clay, IA

Built 1964 Load: 26.6 t ADT: 818

FM 310TH AVE

Fair

Over: L TRUMBULL OUTLET

097352702, Clay, IA

Built 1970 Load: 26.6 t ADT: 968

FM 270TH AVE

Fair

Over: MEADOW CREEK

097361302, Clay, IA

Built 1968 Load: 26.6 t ADT: 50

FORESTVILLE RD

Fair

Over: STREAM

091063504, Clayton, IA

Built 1949 Load: 26.6 t ADT: 560

165TH ST

Fair

Over: ROBERTS CR

094060103, Clayton, IA

Built 1958 Load: 26.6 t ADT: 108

CONCORD AVE

Fair

Over: ROBERTS CREEK

095062604, Clayton, IA

Built 1958 Load: 26.6 t ADT: 30

362ND AVENUE

Fair

Over: SIMMONS CREEK

083E51602, Clinton, IA

Built 1964 Load: 26.6 t ADT: 1,610

FM 195 ST

Fair

Over: MAQUOKETA RIVER

089051903, Delaware, IA

Built 1969 Load: 26.6 t ADT: 835

LOCAL

Fair

Over: STONY CREEK

098382701, Dickinson, IA

Built 1974 Load: 26.6 t ADT: 31

FM

Fair

Over: WHITE WATER CREEK

088013506, Dubuque, IA

Built 1966 Load: 26.6 t ADT: 511

LOCAL

Fair

Over: SOLDIER CREEK

100322102, Emmet, IA

Built 1978 Load: 26.6 t ADT: 11

306TH ST.

Fair

Over: DIBBLE CR

095070203, Fayette, IA

Built 1971 Load: 26.6 t ADT: 33

WHITE TAIL RD

Fair

Over: DRY RUN

095100705, Fayette, IA

Built 1970 Load: 26.6 t ADT: 432

DOGWOOD RD

Fair

Over: BRUSH CREEK

092072106, Fayette, IA

Built 2021 Load: 26.6 t ADT: 10

Showing 4,601-4,650 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.