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

TAFT AVE

Fair

Over: DD #13

096232002, Hancock, IA

Built 1974 Load: 30.9 t ADT: 709

WESTWOOD DR NW

Fair

Over: VINTON DITCH

000000000, Linn, IA

Built 1979 Load: 30.9 t ADT: 472

US 6

Fair

Over: GOSHEN DITCH

3.5 mi. E of jct. IA 70, Muscatine, IA

Built 1981 Load: 30.9 t ADT: 1,740

DEAD END RD

Fair

Over: MOSQUITO CREEK

D10100500, Pottawattamie, IA

Built 1934 Load: 30.9 t ADT: 288

301ST ST

Fair

Over: CREEK

099071903, Winneshiek, IA

Built 1943 Load: 30.9 t ADT: 11

RANCHERO RD

Fair

Over: DRY RUN CREEK

88-14-10-01-10, Black Hawk, IA

Built 1937 Load: 31.0 t ADT: 90

PL RIDGE RD

Fair

Over: TIMBER CREEK

000000000, Carroll, IA

Built 1995 Load: 31.0 t ADT: 584

IA 346

Fair

Over: CEDAR RIVER

0.8 mi E of Jct U.S. 218, Chickasaw, IA

Built 1984 Load: 31.0 t ADT: 3,340

270 TH

Fair

Over: STREAM

083323101, Greene, IA

Built 1973 Load: 31.0 t ADT: 26

LOCAL ROAD

Fair

Over: MUNNS CREEK

087162601, Grundy, IA

Built 1956 Load: 31.0 t ADT: 26

FM 2090 260 ST

Fair

Over: DRAINAGE DITCH #13

096231703, Hancock, IA

Built 1976 Load: 31.0 t ADT: 230

FM

Fair

Over: EAST IOWA RIVER

097243504, Hancock, IA

Built 1975 Load: 31.0 t ADT: 133

S 68TH AVE W

Fair

Over: SMALL STREAM

079213503, Jasper, IA

Built 1950 Load: 31.0 t ADT: 11

FM

Fair

Over: MUSCATINE SLOUGH

075031203, Louisa, IA

Built 1972 Load: 31.0 t ADT: 660

FM

Fair

Over: SPRING CREEK

099461002, Lyon, IA

Built 1971 Load: 31.0 t ADT: 71

LOCAL

Fair

Over: STREAM

077152204, Mahaska, IA

Built 1965 Load: 31.0 t ADT: 50

PLUM DR

Fair

Over: NORTH WALNUT CREEK

0000000000, Polk, IA

Built 2011 Load: 31.0 t ADT: 2,628

LOCAL

Fair

Over: HONEY CREEK

067330501, Taylor, IA

Built 2001 Load: 31.0 t ADT: 15

FM

Fair

Over: MAPLE RIVER

086422605, Woodbury, IA

Built 1979 Load: 31.0 t ADT: 100

US 69

Fair

Over: IOWA RIVER

1.4 mi. S of S jct SR C20, Wright, IA

Built 1933 Load: 31.0 t ADT: 3,210

MARION AVE

Fair

Over: STREAM

77311902, Adair, IA

Built 2012 Load: 31.1 t ADT: 30

LOCAL

Fair

Over: BR YELLOW RIVER

097063305, Allamakee, IA

Built 1991 Load: 31.1 t ADT: 11

CENTER ST

Fair

Over: CEDAR RIVER OVERFLOW

000000000, Black Hawk, IA

Built 1969 Load: 31.1 t ADT: 5,414

FM 250TH ST

Fair

Over: BUFFALO CREEK

088071603, Buchanan, IA

Built 1994 Load: 31.1 t ADT: 69

E16

Fair

Over: MARROWBONE CREEK

085331701, Carroll, IA

Built 1949 Load: 31.1 t ADT: 558

IA 3

Fair

Over: LITTLE SIOUX RIVER

1.5 mi. E of US 59, Cherokee, IA

Built 1960 Load: 31.1 t ADT: 3,230

350TH ST

Fair

Over: OVERFLOW MEADOW CREEK

096361501, Clay, IA

Built 1976 Load: 31.1 t ADT: 878

FM 300TH ST

Fair

Over: LITTLE MEADOW CK

097362101, Clay, IA

Built 1989 Load: 31.1 t ADT: 369

310TH ST

Fair

Over: LITTLE MUDDY CREEK

097362801, Clay, IA

Built 1991 Load: 31.1 t ADT: 21

EB US 30

Fair

Over: AMES CREEK

3.5 MI E OF E JCT US 61, Clinton, IA

Built 1974 Load: 31.1 t ADT: 4,700

W BURLINGTON

Fair

Over: BNSF RR

070032509, Des Moines, IA

Built 1996 Load: 31.1 t ADT: 4,062

FM

Fair

Over: SKUNK CREEK

097172502, Floyd, IA

Built 1985 Load: 31.1 t ADT: 1,365

IA 9

Fair

Over: DRAINAGE DITCH

4.1 mi. W of Jct. U.S. 63, Howard, IA

Built 1976 Load: 31.1 t ADT: 1,630

LOCAL 115TH ST

Fair

Over: BR TURKEY CREEK

099113603, Howard, IA

Built 1987 Load: 31.1 t ADT: 59

LOCAL

Fair

Over: DRAINAGE DITCH

074290501, Madison, IA

Built 1977 Load: 31.1 t ADT: 45

LOCAL

Fair

Over: N SKUNK RIVER

083201901, Marshall, IA

Built 1916 Load: 31.1 t ADT: 30

N 1ST ST

Fair

Over: STREAM

C91100615, Page, IA

Built 1984 Load: 31.1 t ADT: 24

LOCAL

Fair

Over: CYLINDER CREEK

096310501, Palo Alto, IA

Built 1987 Load: 31.1 t ADT: 31

WB I-80

Fair

Over: FOURMILE CREEK

1.4 MILE E OF E JCT I-35, Polk, IA

Built 1959 Load: 31.1 t ADT: 44,500

LOCAL

Fair

Over: SMALL STREAM

079400801, Shelby, IA

Built 1962 Load: 31.1 t ADT: 15

US 65

Fair

Over: TURKEY CREEK

2.8 mi. S of SR J46, Wayne, IA

Built 1987 Load: 31.1 t ADT: 1,240

FM.RT C-20

Fair

Over: DD #125

093232301, Wright, IA

Built 1991 Load: 31.1 t ADT: 970

LOCAL

Fair

Over: DD #66

093233401, Wright, IA

Built 1996 Load: 31.1 t ADT: 5

LOCAL ROAD

Fair

Over: FORK OF RATHBUN LAKE

070191010, Appanoose, IA

Built 1968 Load: 31.2 t ADT: 440

FM

Fair

Over: STERN CREEK

082122203, Benton, IA

Built 1987 Load: 31.2 t ADT: 850

LOCAL

Fair

Over: MUD CREEK

083102602, Benton, IA

Built 1986 Load: 31.2 t ADT: 90

LOCAL

Fair

Over: OPOSSUM CK

084090502, Benton, IA

Built 1986 Load: 31.2 t ADT: 29

FM

Fair

Over: POSSUM CREEK

084100102, Benton, IA

Built 1986 Load: 31.2 t ADT: 34

FM

Fair

Over: BRANCH MUD CREEK

084112303, Benton, IA

Built 1986 Load: 31.2 t ADT: 30

LOCAL

Fair

Over: HINKLE CREEK

085112810, Benton, IA

Built 1987 Load: 31.2 t ADT: 140

Showing 5,951-6,000 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.