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

US 169

Fair

Over: W FORK DES MOINES RIVER

0.6 mi S of IA 3, Humboldt, IA

Built 1997 Load: 29.0 t ADT: 7,100

470TH

Fair

Over: WAPSIPINICON RIVER

100153401, Mitchell, IA

Built 1984 Load: 29.0 t ADT: 295

480TH

Fair

Over: BIG CEDAR RIVER

100182801, Mitchell, IA

Built 1979 Load: 29.0 t ADT: 216

FM

Fair

Over: MILL CREEK

095410401, O'Brien, IA

Built 1984 Load: 29.0 t ADT: 1,087

SB US 75

Fair

Over: STREAM

1.3 mi. N of SR C70, Plymouth, IA

Built 1948 Load: 29.0 t ADT: 7,500

LOCAL

Fair

Over: DD #171 NO LIZARD CK

091312501, Pocahontas, IA

Built 1985 Load: 29.0 t ADT: 20

LOCAL

Fair

Over: LIZARD CK DD #114

092331502, Pocahontas, IA

Built 1977 Load: 29.0 t ADT: 30

I 880 EB

Fair

Over: MOSQUITO CREEK

0.5 MI. E OF JCT. IA 191, Pottawattamie, IA

Built 1966 Load: 29.0 t ADT: 2,900

MCPHERSON AVE

Fair

Over: OVER BNSF RR

000000000, Pottawattamie, IA

Built 1990 Load: 29.0 t ADT: 3,786

FM

Fair

Over: COAL CREEK

076222306, Warren, IA

Built 1984 Load: 29.0 t ADT: 439

FM

Fair

Over: SOUTH CHARITON

069222101, Wayne, IA

Built 1984 Load: 29.0 t ADT: 30

STORY AVE

Fair

Over: STREAM

0874203, Woodbury, IA

Built 2004 Load: 29.0 t ADT: 15

LOCAL

Fair

Over: MCELHANEY CREEK

089442302, Woodbury, IA

Built 1984 Load: 29.0 t ADT: 11

LOCAL

Fair

Over: BIG WHISKEY CREEK

089461302, Woodbury, IA

Built 1982 Load: 29.0 t ADT: 110

IA 17

Fair

Over: BOONE RIVER

2.0 mi. N of jct. SR C70, Wright, IA

Built 1933 Load: 29.0 t ADT: 3,170

FM

Fair

Over: WHITE FOX CREEK

091243102, Wright, IA

Built 1980 Load: 29.0 t ADT: 917

FM

Fair

Over: FROG CREEK

081280903, Dallas, IA

Built 1920 Load: 29.1 t ADT: 428

LOCAL

Fair

Over: FLINT RIVER

070030408, Des Moines, IA

Built 1974 Load: 29.1 t ADT: 73

LOCAL

Fair

Over: LYNN CREEK

073073603, Henry, IA

Built 1973 Load: 29.1 t ADT: 51

LOCAL

Fair

Over: GRITTER CREEK

078113102, Iowa, IA

Built 1980 Load: 29.1 t ADT: 15

IA 78

Fair

Over: STREAM

3.4 MI. W OF JCT. IA 1, Keokuk, IA

Built 1947 Load: 29.1 t ADT: 1,590

FM

Fair

Over: ENGLISH CREEK

075192006, Marion, IA

Built 1978 Load: 29.1 t ADT: 140

432ND ST

Fair

Over: FARM CREEK

00000, Pottawattamie, IA

Built 2011 Load: 29.1 t ADT: 15

LOCAL

Fair

Over: DEER CREEK

083150407, Tama, IA

Built 1940 Load: 29.1 t ADT: 44

LOCAL

Fair

Over: CALEB CREEK

068232201, Wayne, IA

Built 1993 Load: 29.1 t ADT: 15

FM

Fair

Over: MIDDLE RIVER

076302104, Adair, IA

Built 1969 Load: 29.2 t ADT: 1,047

LOCAL

Fair

Over: CREEK

078360504, Audubon, IA

Built 1939 Load: 29.2 t ADT: 30

LOCAL (LWC)

Fair

Over: BR PRAIRIE CK

083122403, Benton, IA

Built 1979 Load: 29.2 t ADT: 40

FM

Fair

Over: PRATT CREEK

085110401, Benton, IA

Built 1982 Load: 29.2 t ADT: 25

FM

Fair

Over: STREAM

089070702, Buchanan, IA

Built 1968 Load: 29.2 t ADT: 982

KEOKUK AVE

Fair

Over: MALONE CR

089091303, Buchanan, IA

Built 2004 Load: 29.2 t ADT: 49

IA 150

Fair

Over: STREAM

3.4 mi. S of SR C57, Buchanan, IA

Built 1984 Load: 29.2 t ADT: 3,890

IA 122 WB

Fair

Over: WILLOW CREEK

4.4 MI. E OF JCT. I-35, Cerro Gordo, IA

Built 1970 Load: 29.2 t ADT: 6,850

HICKORY AVE

Fair

Over: BLOODY RUN

095042802, Clayton, IA

Built 1920 Load: 29.2 t ADT: 108

FIELD ENTRANCE

Fair

Over: SIDE DITCH

067261004, Decatur, IA

Built 1994 Load: 29.2 t ADT: 10

170TH ST

Fair

Over: VOLGA RIVER

093101401, Fayette, IA

Built 1928 Load: 29.2 t ADT: 15

STONE BRIDGE RD

Fair

Over: BR KITTY CREEK

086033204, Jones, IA

Built 1998 Load: 29.2 t ADT: 113

FM

Fair

Over: LONG CREEK

074051204, Louisa, IA

Built 1965 Load: 29.2 t ADT: 290

A50 (BRIDGE ST)

Fair

Over: BIG SIOUX RIVER

098492519, Lyon, IA

Built 1971 Load: 29.2 t ADT: 888

LOCAL ROAD

Fair

Over: OVERFLOW

099431102, Lyon, IA

Built 1900 Load: 29.2 t ADT: 26

LOCAL

Fair

Over: SMALL

076273603, Madison, IA

Built 1989 Load: 29.2 t ADT: 11

FM

Fair

Over: FOUR MILE CREEK

079230803, Polk, IA

Built 1966 Load: 29.2 t ADT: 3,715

400TH STREET

Fair

Over: DRAINAGE

077401102, Pottawattamie, IA

Built 1948 Load: 29.2 t ADT: 40

NB I-35

Fair

Over: BEAR CREEK

3.3 MILES SOUTH OF SR E18, Story, IA

Built 1967 Load: 29.2 t ADT: 15,250

FM

Fair

Over: DES MOINES RIVER

069102725, Van Buren, IA

Built 1960 Load: 29.2 t ADT: 1,120

LOCAL ROAD

Fair

Over: BRANCH OTTER CREEK

074233002, Warren, IA

Built 1970 Load: 29.2 t ADT: 41

LOCAL

Fair

Over: BOONE RIVER

091260503, Wright, IA

Built 1986 Load: 29.2 t ADT: 50

FM

Fair

Over: CREEK

078343004, Audubon, IA

Built 1920 Load: 29.3 t ADT: 60

LOCAL

Fair

Over: SMALL STREAM

091172202, Butler, IA

Built 1900 Load: 29.3 t ADT: 30

LOCAL

Fair

Over: LITTLE WAPSIPINICON

096132003, Chickasaw, IA

Built 1976 Load: 29.3 t ADT: 49

Showing 5,201-5,250 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.