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

T-53 (S AVE)

Unknown

Over: US 20

2.0 mi. W of SR T55, Grundy, IA

Built 1999 ADT: 13,600

US 20 EB

Unknown

Over: SR T55

AT JUNCTION WITH SR T55, Grundy, IA

Built 2000 ADT: 945

WB US 20

Unknown

Over: SR T55

AT JUNCTION WITH SR T55, Grundy, IA

Built 2000 ADT: 945

US 20 EB

Unknown

Over: IA 14

AT JUNCTION IA 14, Grundy, IA

Built 2000 ADT: 2,400

T47 (Q AVE)

Unknown

Over: US 20

3.0 MILES E OF JCT IA 14, Grundy, IA

Built 1999 ADT: 13,600

VISTA AVE

Unknown

Over: US 20

1.6 MILES EAST OF SR T55, Grundy, IA

Built 1999 ADT: 14,500

US 20 WB

Unknown

Over: IA 14

AT JUNCTION WITH IA 14, Grundy, IA

Built 2000 ADT: 2,400

D AVENUE

Unknown

Over: US 20

2.0 MILES W OF JCT SR T19, Grundy, IA

Built 2003 ADT: 9,900

B AVENUE

Unknown

Over: US 20

4.0 MILES W OF JCT SR T19, Grundy, IA

Built 2003 ADT: 9,900

L AVENUE

Unknown

Over: US 20

2.0 MILES W OF JCT IA 14, Grundy, IA

Built 2003 ADT: 10,100

J AVENUE

Unknown

Over: US 20

4.0 MILES W OF JCT IA 14, Grundy, IA

Built 2003 ADT: 10,100

US 20 WB

Unknown

Over: H AVENUE

2.0 MILES EAST JCT SR T19, Grundy, IA

Built 2003 ADT: 50

US 20 EB

Unknown

Over: H AVENUE

2.0 mi. E of jct SR T19, Grundy, IA

Built 2003 ADT: 50

US 20 WB

Unknown

Over: SR T19

AT JUNCTION WITH SR T19, Grundy, IA

Built 2003 ADT: 740

US 20 EB

Unknown

Over: T 19

AT JUNCTION WITH SR T19, Grundy, IA

Built 2003 ADT: 740

SR D-65

Unknown

Over: I-35

AT JUNCTION WITH I-35, Hamilton, IA

Built 1965 ADT: 26,100

NB I-35

Unknown

Over: CO RD D-25

AT JUNCTION WITH SR D25, Hamilton, IA

Built 1974 ADT: 1,090

I 35 SB

Unknown

Over: SR D25

AT JUNCTION WITH SR D25, Hamilton, IA

Built 1974 ADT: 1,090

NB I-35

Unknown

Over: CC RR & 210TH ST

1.1 MI N OF SR D25, Hamilton, IA

Built 1972 ADT: 40

SR D-20

Unknown

Over: I-35

AT JUNCTION WITH D20, Hamilton, IA

Built 1972 ADT: 16,000

SB I-35

Unknown

Over: CC RR & 210TH ST

1.1 MILES NORTH OF SR D25, Hamilton, IA

Built 1972 ADT: 20

LOCKWOOD AVE

Unknown

Over: US 20

3.0 MILE E OF E JCT IA 17, Hamilton, IA

Built 1975 ADT: 10,100

EB US 20

Unknown

Over: R-38

AT JUNCTION WITH SR R38, Hamilton, IA

Built 1975 ADT: 235

WB US 20

Unknown

Over: R-38

AT JUNCTION WITH SR R38, Hamilton, IA

Built 1975 ADT: 235

POPLAR GROVE AVE

Unknown

Over: US 20

2.0 MILES W OF JCT US 69, Hamilton, IA

Built 1975 ADT: 10,300

IA 17

Unknown

Over: US 20

AT NORTH JCT WITH US 20, Hamilton, IA

Built 1978 ADT: 9,700

EB 20 & SB 17

Unknown

Over: R-27

0.8 MI W OF E JCT IA 17, Hamilton, IA

Built 1978 ADT: 475

WB 20 & NB 17

Unknown

Over: R-27

0.8 MI W OF E JCT IA 17, Hamilton, IA

Built 1978 ADT: 475

CO RD R 61

Unknown

Over: U.S. 20

0.5 MILE EAST OF JCT I-35, Hamilton, IA

Built 1990 ADT: 3,450

FM RD R 77

Unknown

Over: US 20

2.5 MILES E OF JCT I-35, Hamilton, IA

Built 1990 ADT: 8,700

ZIEGLER AVE

Unknown

Over: US 20

2.0 MILES EAST OF SR R77, Hamilton, IA

Built 1990 ADT: 8,900

EB US 20

Unknown

Over: CO RD S-27

AT JUNCTION WITH SR S27, Hardin, IA

Built 1990 ADT: 545

WB US 20

Unknown

Over: CO RD S-27

AT JUNCTION WITH SR S27, Hardin, IA

Built 1990 ADT: 545

D AVENUE

Unknown

Over: US 20

2.0 MILES W OF SR S27, Hardin, IA

Built 1990 ADT: 9,600

H AVENUE

Unknown

Over: US 20

2.0 MILES E OF JCT SR S27, Hardin, IA

Built 1990 ADT: 9,400

JJ AVENUE

Unknown

Over: US 20

2.0 MILES W OF JCT US 65, Hardin, IA

Built 1990 ADT: 9,400

US 20 EB

Unknown

Over: US 65

AT JUNCTION WITH US 65, Hardin, IA

Built 2003 ADT: 1,820

US 20 WB

Unknown

Over: US 65

AT JUNCTION WITH US 65, Hardin, IA

Built 2003 ADT: 1,820

US 20 EB

Unknown

Over: D 35 (ELM ST)

3.4 MILES E OF JCT US 65, Hardin, IA

Built 2003 ADT: 125

US 20 WB

Unknown

Over: D 35 (ELM ST)

3.4 MILES E OF JCT US 65, Hardin, IA

Built 2003 ADT: 125

V AVENUE

Unknown

Over: US 20

2.4 MILES W OF JCT SR S56, Hardin, IA

Built 2003 ADT: 9,300

T AVENUE

Unknown

Over: US 20

1.2 MILES E OF JCT SR D35, Hardin, IA

Built 2003 ADT: 9,300

D35

Unknown

Over: US 20

AT JUNCTION SR D35, Hardin, IA

Built 2003 ADT: 9,000

S 56

Unknown

Over: US 20

AT JUNCTION WITH SR S56, Hardin, IA

Built 2003 ADT: 9,500

LOCAL RD

Unknown

Over: I-29

1.0 MI. N OF JCT. US 30, Harrison, IA

Built 1966 ADT: 16,100

SR X-23

Unknown

Over: RELOC. US 34

At Jct. U.S. 34, Henry, IA

Built 1998 ADT: 5,500

255TH STREET

Unknown

Over: U.S. 218

1.8 mi. S of S Jct. US 34, Henry, IA

Built 2001 ADT: 7,000

S IRIS ST

Unknown

Over: US 218

0.4 mi. S of S Jct. US 34, Henry, IA

Built 2001 ADT: 5,800

US 218 NB

Unknown

Over: US 34

At the S Jct. U.S. 34, Henry, IA

Built 2001 ADT: 840

US 218 SB

Unknown

Over: US 34

At S jct. US 34, Henry, IA

Built 2001 ADT: 840

Showing 301-350 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.