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

Good

Over: SM STREAM

097442602, Sioux, IA

Built 2001 Load: 99.9 t ADT: 80

LOCAL

Good

Over: SMALL STREAM

097442902, Sioux, IA

Built 1995 Load: 99.9 t ADT: 71

INDIAN AVE

Good

Over: NO NAME CREEK

097443102, Sioux, IA

Built 2016 Load: 99.9 t ADT: 45

LOCAL

Good

Over: SMALL

W of 35 Sheridan, Sioux, IA

Built 2009 Load: 99.9 t ADT: 60

FM

Good

Over: DRY CREEK

097451501, Sioux, IA

Built 2010 Load: 99.9 t ADT: 34

LOCAL

Good

Over: SMALL

097452201, Sioux, IA

Built 2003 Load: 99.9 t ADT: 45

LOCAL

Good

Over: SM STREAM

097452402, Sioux, IA

Built 1997 Load: 99.9 t ADT: 60

FM

Good

Over: SM STREAM

097453504, Sioux, IA

Built 1933 Load: 99.9 t ADT: 1,416

LOCAL

Good

Over: SM STREAM

097453602, Sioux, IA

Built 2001 Load: 99.9 t ADT: 100

K 20 (270TH ST)

Good

Over: NO NAME CREEK

097470301, Sioux, IA

Built 2013 Load: 99.9 t ADT: 34

LOCAL

Good

Over: SMALL STREAM

097470302, Sioux, IA

Built 1986 Load: 99.9 t ADT: 40

LOCAL

Good

Over: SMALL STREAM

097470801, Sioux, IA

Built 1985 Load: 99.9 t ADT: 50

LOCAL

Good

Over: SM STREAM

097470902, Sioux, IA

Built 1997 Load: 99.9 t ADT: 20

LOCAL

Good

Over: SMALL STREAM

097471002, Sioux, IA

Built 1984 Load: 99.9 t ADT: 50

LOCAL

Good

Over: SMALL STREAM

097471501, Sioux, IA

Built 1984 Load: 99.9 t ADT: 40

LOCAL

Good

Over: SM STREAM

097471902, Sioux, IA

Built 2002 Load: 99.9 t ADT: 40

FM

Good

Over: NO NAME CREEK

097473001, Sioux, IA

Built 1988 Load: 99.9 t ADT: 159

LOCAL

Good

Over: STREAM

097482403, Sioux, IA

Built 1985 Load: 99.9 t ADT: 110

LOCAL

Good

Over: SMALL STREAM

094472702, Sioux, IA

Built 1998 Load: 99.9 t ADT: 40

LOCAL

Good

Over: SMALL STREAM

094430104, Sioux, IA

Built 2001 Load: 99.9 t ADT: 122

LOCAL

Good

Over: SMALL

094440602, Sioux, IA

Built 1984 Load: 99.9 t ADT: 30

LOCAL

Good

Over: SMALL

094452201, Sioux, IA

Built 1996 Load: 99.9 t ADT: 40

LOCAL

Good

Over: SMALL

094462201, Sioux, IA

Built 1986 Load: 99.9 t ADT: 15

LOCAL

Good

Over: SMALL

094462302, Sioux, IA

Built 1986 Load: 99.9 t ADT: 60

B 62

Good

Over: SMALL

094483401, Sioux, IA

Built 2003 Load: 99.9 t ADT: 34

LOCAL

Good

Over: SMALL

095453101, Sioux, IA

Built 1974 Load: 99.9 t ADT: 50

LOCAL

Good

Over: SMALL

095473301, Sioux, IA

Built 1977 Load: 99.9 t ADT: 45

LOCAL

Good

Over: SMALL

095432601, Sioux, IA

Built 1987 Load: 99.9 t ADT: 40

LOCAL

Good

Over: SMALL

096470202, Sioux, IA

Built 1983 Load: 99.9 t ADT: 31

LOCAL

Good

Over: SMALL

094441701, Sioux, IA

Built 1977 Load: 99.9 t ADT: 808

LOCAL

Good

Over: SMALL

094460102, Sioux, IA

Built 1977 Load: 99.9 t ADT: 34

LOCAL

Good

Over: SMALL

094460102, Sioux, IA

Built 1977 Load: 99.9 t ADT: 34

K42

Good

Over: SMALL

094462402, Sioux, IA

Built 2005 Load: 99.9 t ADT: 30

470TH ST

Good

Over: SMALL

094471701, Sioux, IA

Built 1997 Load: 99.9 t ADT: 60

LOCAL

Good

Over: SMALL

095472201, Sioux, IA

Built 1976 Load: 99.9 t ADT: 569

LOCAL

Good

Over: SMALL

096472402, Sioux, IA

Built 2004 Load: 99.9 t ADT: 60

LOCAL

Good

Over: SMALL

095460102, Sioux, IA

Built 2006 Load: 99.9 t ADT: 1,236

MARSH AVE

Good

Over: SMALL

095432402, Sioux, IA

Built 2008 Load: 99.9 t ADT: 26

LOCAL

Good

Over: SMALL

095432501, Sioux, IA

Built 2008 Load: 99.9 t ADT: 26

GRANT AVE

Good

Over: CREEK

096450802, Sioux, IA

Built 2012 Load: 99.9 t ADT: 34

350TH ST

Good

Over: SM STREAM

096431801, Sioux, IA

Built 2013 Load: 99.9 t ADT: 45

HARRISON AVE

Good

Over: SMALL STREAM

097452202, Sioux, IA

Built 2014 Load: 99.9 t ADT: 71

JEFFERSON AVE

Good

Over: SMALL STREAM

South 975, Sioux, IA

Built 2015 Load: 99.9 t ADT: 30

DOVE AVE

Good

Over: SMALL STREAM

South 1,450, Sioux, IA

Built 2015 Load: 99.9 t ADT: 30

KENNEDY AVE

Good

Over: SMALL STREAM

096440102, Sioux, IA

Built 2016 Load: 99.9 t ADT: 90

360TH ST

Good

Over: SMALL STREAM

096442301, Sioux, IA

Built 2017 Load: 99.9 t ADT: 45

K24 DOGWOOD AVE

Good

Over: SMALL STREAM

095473602010, Sioux, IA

Built 2020 Load: 99.9 t ADT: 30

IA 175

Good

Over: SKILLET CREEK

0.3 mi. S of Sec. Rd. P73, Webster, IA

Built 2018 Load: 99.9 t ADT: 1,040

US 20

Good

Over: HOLLIDAY CREEK

1.0 mi. E of SR P39, Webster, IA

Built 1986 Load: 99.9 t ADT: 9,800

US 75

Good

Over: STREAM

0.1 mi. N of 46 St./D12, Woodbury, IA

Built 2000 Load: 99.9 t ADT: 10,400

Showing 16,551-16,600 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.