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: SMALL STREAM

095431103, Sioux, IA

Built 1984 Load: 34.3 t ADT: 1,147

V56

Fair

Over: SO LITTLE FOX CREEK

068113210, Van Buren, IA

Built 1985 Load: 34.3 t ADT: 820

HAMILTN AT 35TH

Fair

Over: PERRY CREEK

000000000, Woodbury, IA

Built 1970 Load: 34.3 t ADT: 14,345

LOCAL

Fair

Over: CREEK

079011404, Cedar, IA

Built 1974 Load: 34.4 t ADT: 15

400TH AVE.

Fair

Over: SOUTH BRANCH ELK RIVER

083E63102, Clinton, IA

Built 1989 Load: 34.4 t ADT: 80

ASPEN AVENUE

Fair

Over: MIDDLE NODAWAY RIVER

072352902, Adams, IA

Built 1992 Load: 34.5 t ADT: 60

CLEAR CREEK WMA

Fair

Over: CLEAR CREEK

100052705, Allamakee, IA

Built 1900 Load: 34.5 t ADT: 15

US 20

Fair

Over: DRAINAGE

2.4 MI. E OF E JCT. I-380, Black Hawk, IA

Built 1980 Load: 34.5 t ADT: 10,700

FM

Fair

Over: WAPSINONOC CREEK

079032102, Cedar, IA

Built 1994 Load: 34.5 t ADT: 40

LOCAL

Fair

Over: CREEK

095142106, Chickasaw, IA

Built 1970 Load: 34.5 t ADT: 91

FRANKLIN AVE

Fair

Over: BOYLAN CR

093191104, Franklin, IA

Built 1952 Load: 34.5 t ADT: 5

IA 57

Fair

Over: W BRANCH CEDAR RIVER

1.6 MILES WEST OF SR S56, Hardin, IA

Built 1960 Load: 34.5 t ADT: 1,900

US 34 EB

Fair

Over: MITCHELL CREEK

3.6 mi. W of Jct. IA 1, Jefferson, IA

Built 2008 Load: 34.5 t ADT: 2,485

WB US 30

Fair

Over: CEDAR RIVER

0.5 mi. W of E Jct US 151, Linn, IA

Built 1975 Load: 34.5 t ADT: 11,750

400TH

Fair

Over: CREEK

098150201, Mitchell, IA

Built 1978 Load: 34.5 t ADT: 29

FOOTHILL AVE

Fair

Over: ROCK CREEK

098183602, Mitchell, IA

Built 1981 Load: 34.5 t ADT: 26

FM

Fair

Over: RED OAK CREEK

072382705, Montgomery, IA

Built 1968 Load: 34.5 t ADT: 1,275

IA 148

Fair

Over: W.FORK 102 RIVER

0.1 MI. N OF SR J20, Taylor, IA

Built 1961 Load: 34.5 t ADT: 1,200

430 TH

Fair

Over: STREAM

099202301, Worth, IA

Built 1968 Load: 34.5 t ADT: 25

LOCAL

Fair

Over: BR GRAND RIVER

075300804, Adair, IA

Built 1961 Load: 34.6 t ADT: 15

LOCAL

Fair

Over: SMALL

077311102, Adair, IA

Built 1997 Load: 34.6 t ADT: 21

FM

Fair

Over: SOUTH WEST CREEK

072250603, Clarke, IA

Built 1971 Load: 34.6 t ADT: 658

FM 320TH AVE

Fair

Over: DD #22

094352602, Clay, IA

Built 2003 Load: 34.6 t ADT: 20

CRYSTAL RD

Fair

Over: HEWETT CREEK

092061404, Clayton, IA

Built 1977 Load: 34.6 t ADT: 44

BUSH RD

Fair

Over: DEEP CREEK

093063103, Clayton, IA

Built 1978 Load: 34.6 t ADT: 275

252ND ST

Fair

Over: SILVER CREEK

081E32305, Clinton, IA

Built 1971 Load: 34.6 t ADT: 760

185TH AVENUE

Fair

Over: PRAIRIE CREEK

083E20404, Clinton, IA

Built 1973 Load: 34.6 t ADT: 840

110TH ST.

Fair

Over: PRAIRIE CREEK

083E20901, Clinton, IA

Built 1975 Load: 34.6 t ADT: 90

LOCAL

Fair

Over: SMALL CREEK

078312404, Guthrie, IA

Built 1977 Load: 34.6 t ADT: 45

FM SW 500TH ST

Fair

Over: DEER CREEK

078081701, Johnson, IA

Built 1973 Load: 34.6 t ADT: 690

DEER CK RD

Fair

Over: DEER CREEK

079070102, Johnson, IA

Built 1972 Load: 34.6 t ADT: 1,363

FM

Fair

Over: UNNAMED STREAM

076131301, Keokuk, IA

Built 1976 Load: 34.6 t ADT: 40

US 61

Fair

Over: OVERFLOW IOWA RIVER

1.1 Mi. N of SR G62, Louisa, IA

Built 1985 Load: 34.6 t ADT: 4,950

FM-KANE AV

Fair

Over: KEG CREEK

072432703, Mills, IA

Built 2004 Load: 34.6 t ADT: 190

FA-BROTHERS AVE

Fair

Over: MUD CREEK

073411001, Mills, IA

Built 1978 Load: 34.6 t ADT: 131

IA 22

Fair

Over: SWEETLAND CREEK

4.2 MI. E OF JCT. IA 38, Muscatine, IA

Built 1978 Load: 34.6 t ADT: 1,730

LOCAL

Fair

Over: CREEK

077E10404, Muscatine, IA

Built 1956 Load: 34.6 t ADT: 104

LOCAL

Fair

Over: DD 176

096333201, Palo Alto, IA

Built 2005 Load: 34.6 t ADT: 15

470TH STREET

Fair

Over: STREAM

077391304, Pottawattamie, IA

Built 1979 Load: 34.6 t ADT: 60

330TH STREET

Fair

Over: STREAM

077413402, Pottawattamie, IA

Built 1977 Load: 34.6 t ADT: 45

LOCAL

Fair

Over: SOUTH ENGLISH RIVER

078142001, Poweshiek, IA

Built 1953 Load: 34.6 t ADT: 26

GEO. THUENEN DR

Fair

Over: IMRL LINK

Bettendorf, IA, Scott, IA

Built 1998 Load: 34.6 t ADT: 95

LOCAL

Fair

Over: STREAM

075331304, Adair, IA

Built 1991 Load: 34.7 t ADT: 41

LOCAL

Fair

Over: WATERLOO CREEK

100062413, Allamakee, IA

Built 1983 Load: 34.7 t ADT: 295

X52-GREATRVR RD

Fair

Over: DRAINAGE DITCH

098031104, Allamakee, IA

Built 2013 Load: 34.7 t ADT: 570

LOCAL

Fair

Over: STREAM

083121101, Benton, IA

Built 1958 Load: 34.7 t ADT: 20

W REINBECK RD

Fair

Over: TRIB TO MILLER CREEK

87-13-28-01-10, Black Hawk, IA

Built 2001 Load: 34.7 t ADT: 11

300TH AVE

Fair

Over: STREAM

097353302, Clay, IA

Built 2000 Load: 34.7 t ADT: 11

RAILWAY ST

Fair

Over: ELK CREEK

000000000, Clay, IA

Built 1996 Load: 34.7 t ADT: 884

FM

Fair

Over: SO RACCOON RIVER

078281610, Dallas, IA

Built 1993 Load: 34.7 t ADT: 1,474

Showing 7,451-7,500 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.