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

Data updated May 2026

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

Iowa38.5%40.4%21.1%GoodFairPoor (structurally 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.

WV

West Virginia

16.02% top marginal rate
Structure
Progressive
Burden @ $100K
$7,679

SD

South Dakota

16.24% top marginal rate
Structure
Progressive
Burden @ $100K
$5,905
Selected

IA

Iowa

20.01% top marginal rate
Structure
Progressive
Burden @ $100K
$20,753

VI

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

IA 25

Unknown

Over: I-80

AT JCT. I-80, Adair, IA

Built 1958 ADT: 23,600

SR N-54

Unknown

Over: I-80

AT JCT. SR N-54, Adair, IA

Built 1958 ADT: 21,000

FONTANELLE ROAD

Unknown

Over: I-80

5.9 MI. W OF JCT. IA 25, Adair, IA

Built 1958 ADT: 23,100

SR 54TH ST TRL

Unknown

Over: I-380

1.6 MI. S OF IOWA 150, Benton, IA

Built 1981 ADT: 18,900

I 380 NB

Unknown

Over: IA 150

At Jct. Iowa 150, Benton, IA

Built 1982 ADT: 1,405

I 380 SB

Unknown

Over: IA 150

At jct. Iowa 150, Benton, IA

Built 1982 ADT: 1,405

30TH AVE

Unknown

Over: I-380

1.5 MILES N OF JCT IA 150, Benton, IA

Built 1984 ADT: 17,700

51 STREET

Unknown

Over: I-380

2.8 mi. S of Jct. SR D48, Benton, IA

Built 1984 ADT: 17,700

IA 21

Unknown

Over: US 30

IA 21 U.S. 30 INTERCHANGE, Benton, IA

US 218

Unknown

Over: US 30

US 218/US 30 INTERCHANGE, Benton, IA

Built 2017 ADT: 7,700

RIVER FOREST RD

Unknown

Over: I-380

0.8 MI. S OF S JCT. 218, Black Hawk, IA

Built 1981 ADT: 32,200

MLK JR DR

Unknown

Over: LANE ST

CITY BRIDGE NO. 52, Black Hawk, IA

Built 1996 ADT: 998

NB US 218

Unknown

Over: BLACK HAWK CK & RD

0.2 mi. N of Jct. U.S. 63, Black Hawk, IA

Built 1991 ADT: 861

SB US 218

Unknown

Over: BLACK HAWK CK & RD

0.2 mi. N of Jct. U.S. 63, Black Hawk, IA

Built 1991 ADT: 861

US 218 NB

Unknown

Over: FLETCHER AVE

0.6 Mi. N of JCT. US 63, Black Hawk, IA

Built 1991 ADT: 2,105

US 218 SB

Unknown

Over: FLETCHER AVE

0.8 mi. N of Jct U.S. 63, Black Hawk, IA

Built 1991 ADT: 2,105

ANSBOROUGH AVE

Unknown

Over: US 218

IN WATERLOO, Black Hawk, IA

Built 1991 ADT: 22,200

US 218 SB

Unknown

Over: SB US 63

At jct. U.S. #63, Black Hawk, IA

Built 1991 ADT: 3,200

SB US 218

Unknown

Over: NB US 63

3.6 mi. N of US 20, Black Hawk, IA

Built 1991 ADT: 2,700

NB IA 27

Unknown

Over: IA 57

AT JCT. IA 57 & US 218, Black Hawk, IA

Built 1994 ADT: 9,800

IA 27 SB

Unknown

Over: IA 57

AT JCT. IA. 57 & US 218, Black Hawk, IA

Built 1994 ADT: 7,800

NB IA 27

Unknown

Over: SO MAIN ST

.3 mi S of University Ave, Black Hawk, IA

Built 1993 ADT: 3,150

SB IA 27

Unknown

Over: SO MAIN ST

.3 mi S of University Ave, Black Hawk, IA

Built 1993 ADT: 3,150

IA 27

Unknown

Over: UNIVERSITY AVE

2.1 MI. S of U.S. 218, Black Hawk, IA

Built 1993 ADT: 8,200

NB IA 27

Unknown

Over: SEERLEY BLVD

0.2 mi N of University Av, Black Hawk, IA

Built 1994 ADT: 1,175

SB IA 27

Unknown

Over: SEERLEY BLVD

0.2 mi N of University Av, Black Hawk, IA

Built 1994 ADT: 1,175

NB IA 27

Unknown

Over: 18TH ST

1.6 mi. S of US 218, Black Hawk, IA

Built 1994 ADT: 1,645

SB IA 27

Unknown

Over: 18TH ST

1.6 Mi. S of US 218, Black Hawk, IA

Built 1994 ADT: 1,645

NB IA 27

Unknown

Over: WATERLOO RD

1.3 mi. S of Jct. US 218, Black Hawk, IA

Built 1995 ADT: 2,500

SB IA 27

Unknown

Over: WATERLOO RD

1.3 mi. S of Jct. US 218, Black Hawk, IA

Built 1995 ADT: 2,500

RAMP J (SB)

Unknown

Over: IA 57

AT JCT. OF IA 57, Black Hawk, IA

Built 1995 ADT: 16,600

RAMP J(SB)US218

Unknown

Over: IA 58

0.1 MI. N OF JCT. IA. #57, Black Hawk, IA

Built 1995 ADT: 17,700

NB US 218

Unknown

Over: LINCOLN ST & OVERFLO

0.3 mi. N of jct. IA 57, Black Hawk, IA

Built 1995 ADT: 1,200

SB US 218

Unknown

Over: LINCOLN ST & OVERFLO

0.3 Mi. N of Jct. IA 57, Black Hawk, IA

Built 1995 ADT: 1,200

RAMP A (SB)

Unknown

Over: LINCOLN ST & OVERFLO

0.1 MI. N OF JCT. IA 57, Black Hawk, IA

Built 1995 ADT: 2,400

LONE TREE RD

Unknown

Over: US 218

1.7 mi N of IA 57 & IA 58, Black Hawk, IA

Built 1995 ADT: 20,500

DUNKERTON RD

Unknown

Over: US 218

At Jct. Dunkerton Rd., Black Hawk, IA

Built 1995 ADT: 21,200

EB 20

Unknown

Over: US 218

AT W. JCT. I-380, Black Hawk, IA

Built 1983 ADT: 3,050

US 20 WB

Unknown

Over: NB/WB RAMP I-380

AT EAST JCT. I-380, Black Hawk, IA

Built 1980 ADT: 4,200

US 20 EB

Unknown

Over: NB/WB RAMP I-380

AT E JCT. I-380, Black Hawk, IA

Built 1980 ADT: 4,200

SB RP I-380 &20

Unknown

Over: I-380 & 20

AT EAST JCT. I-380, Black Hawk, IA

Built 1980 ADT: 12,500

V49(RAYMOND RD)

Unknown

Over: I-380

AT JCT. S.R. V49, Black Hawk, IA

Built 1980 ADT: 26,700

SR V51

Unknown

Over: U.S. 20

At Jct. SR V51, Black Hawk, IA

Built 1980 ADT: 10,300

FM CO V062

Unknown

Over: US 20

2.4 MI. W OF SR V65., Black Hawk, IA

Built 1980 ADT: 10,800

SPRING CREEK RD

Unknown

Over: US 20

0.9 mi. W of Jct. SR V65, Black Hawk, IA

Built 1980 ADT: 10,800

WB US 20

Unknown

Over: US 63 SERGEANT RD TRAIL

AT JCT. U.S. 63, Black Hawk, IA

Built 1983 ADT: 4,400

FM D-38

Unknown

Over: I-380

2.8 mi. S of S Jct. US 20, Black Hawk, IA

Built 1984 ADT: 16,200

W 4TH ST

Unknown

Over: US 20

0.5 MI. E OF JCT. US 63, Black Hawk, IA

Built 1984 ADT: 28,100

ANSBOROUGH AVE

Unknown

Over: US 20

1.5 MI. W OF JCT. IA 21, Black Hawk, IA

Built 1984 ADT: 23,400

KIMBALL AVE

Unknown

Over: US 20

0.5 MI. W OF JCT. IA 21, Black Hawk, IA

Built 1984 ADT: 25,900

Showing 1-50 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.

Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.