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

IA 100 WB

Unknown

Over: US 30

US 30 RAMP H, Linn, IA

Built 2018 ADT: 13,100

IA 100WB TO US30EB

Unknown

Over: US 30 EB TO IA 100 EB

1 mi S IA100/SR E48 INTCH, Linn, IA

Built 2018 ADT: 1,000

IA 100 EB

Unknown

Over: 16TH AVE ACCESS

IA-100/US-30 INTERCHANGE, Linn, IA

Built 2017 ADT: 18

IA 100 WB

Unknown

Over: 16TH AVE ACCESS RD

IA-100/US-30 INTERCHANGE, Linn, IA

Built 2017 ADT: 18

E 48 E AVE

Unknown

Over: IA 100

IA100 & SR E48 INTCHG., Linn, IA

Built 2018 ADT: 3,300

IA 100 EB

Unknown

Over: ELLIS RD SILVER CREEK

2.8 Mi. N of US 218/30, Linn, IA

Built 2016 ADT: 360

IA 100 WB

Unknown

Over: ELLIS RD SILVER CREEK

2.8 Mi. N of US 218/30, Linn, IA

Built 2016 ADT: 360

TOWER TERRACE WB

Unknown

Over: I 380

2.4 mi. S Jct. SR E34, Linn, IA

ADT: 14,500

IA 92

Unknown

Over: MAIN ST & COLLINS RD

0.3 mi W of Jct. IA 70, Louisa, IA

Built 1995 ADT: 2,780

US 61 SB

Unknown

Over: IA 92

US 61 & IA 92 INTERCHANGE, Louisa, IA

Built 2017 ADT: 1,165

US 61 SB IA 92 WB

Unknown

Over: 170TH ST

at Jct. of SR 170 St., Louisa, IA

Built 2017 ADT: 255

US 34

Unknown

Over: RUSSELL BLVD BNSF UP RR

0.4 mi. E of Jct. IA 14, Lucas, IA

Built 1960 ADT: 70

IA 14

Unknown

Over: US 34

AT JCT. US 34, Lucas, IA

Built 1960 ADT: 1,920

SR P-48

Unknown

Over: I-80

At jct. of SR P48, Madison, IA

Built 1959 ADT: 26,100

EB/SB IA 163

Unknown

Over: IA 92

AT JCT. OF IA 92, Mahaska, IA

Built 1996 ADT: 3,650

WB/NB IA 163

Unknown

Over: IA 92

AT JCT. OF IA 92, Mahaska, IA

Built 1996 ADT: 3,650

INDIAN WAY

Unknown

Over: IA 163

0.8 MI. E OF JCT. IA 92, Mahaska, IA

Built 1996 ADT: 7,900

263RD ST

Unknown

Over: IA 163

1.7 MI. E OF JCT. IA 92, Mahaska, IA

Built 1995 ADT: 7,900

US 63 SB

Unknown

Over: IA 163

AT JCT. OF IA 163, Mahaska, IA

Built 1996 ADT: 7,500

SR G 55

Unknown

Over: US 63 & IA 163

AT W JCT. OF Iowa 163, Mahaska, IA

Built 1996 ADT: 5,800

MERINO AVE

Unknown

Over: US 63

1.8 mi. N of Jct. IA #137, Mahaska, IA

Built 2002 ADT: 10,200

IA 5

Unknown

Over: IA 92 (S JCT)

At S jct. Iowa 92, Marion, IA

Built 1978 ADT: 3,010

OLD HWY 92

Unknown

Over: IA 92

3.9 MI. E OF E JCT.IOWA 5, Marion, IA

Built 1978 ADT: 3,840

CLARK ST

Unknown

Over: IA 163

2.5 MI. E OF SR G-28., Marion, IA

Built 1994 ADT: 7,100

IDAHO DR

Unknown

Over: IA 163

1.3 mi. W of SR T17, Marion, IA

Built 1994 ADT: 10,300

SR G28

Unknown

Over: IA 163

At Jct SR G28/Wash. St., Marion, IA

Built 1994 ADT: 9,100

IA 163 EB

Unknown

Over: SR G5T

At jct. SR G5T, Marion, IA

Built 1996 ADT: 1,165

IA 163 WB

Unknown

Over: SR G5T

Jct. SR G5T, Marion, IA

Built 1996 ADT: 1,165

IA 92 & SB IA 5

Unknown

Over: 110TH PLACE

1.6 mi. N of jct. IA 14, Marion, IA

Built 1978 ADT: 135

IA 92 & NB IA 5

Unknown

Over: 110TH PLACE

1.6 mi. N of jct. IA 14, Marion, IA

Built 1978 ADT: 135

SB IA 5 & IA 92

Unknown

Over: IA 14

At jct. Iowa 14, Marion, IA

Built 1978 ADT: 3,300

NB IA 5 & IA 92

Unknown

Over: IA 14

AT Jct. Iowa 14, Marion, IA

Built 1978 ADT: 3,300

IA 92 EB & IA 5 SB

Unknown

Over: 135TH PLACE

1.0 MI. S OF JCT IOWA #14, Marion, IA

Built 1978 ADT: 75

IA 92 WB & IA 5 NB

Unknown

Over: 135TH PLACE

1.0 MI. S OF JCT. IA 14, Marion, IA

Built 1978 ADT: 75

IA 92

Unknown

Over: 165TH AVE

2.0 MI. E OF E JCT IOWA 5, Marion, IA

Built 1978 ADT: 180

MCKIMBER STREET

Unknown

Over: IA 5 & IA 92

2.0 mi. N Jct. IA 14, Marion, IA

Built 1978 ADT: 4,920

SO CENTER ST

Unknown

Over: RR AND MADISON ST

084183504, Marshall, IA

Built 1951 ADT: 1,370

SB IA 330

Unknown

Over: US 30

AT JUNCTION US 30, Marshall, IA

Built 2006 ADT: 3,350

S 3RD ST

Unknown

Over: UP RR & ST

084183500, Marshall, IA

Built 1984 ADT: 600

MARSH AVE

Unknown

Over: US 30

1.1 MI. E OF JCT. IA 330, Marshall, IA

Built 1995 ADT: 13,200

EB US 30

Unknown

Over: IA 14

AT JUNCTION WITH IA 14, Marshall, IA

Built 1995 ADT: 4,750

WB US 30

Unknown

Over: IA 14

AT THE JCT. OF IA 14, Marshall, IA

Built 1995 ADT: 4,750

US 30 EB

Unknown

Over: OAKS AVE

2.5 MILES W OF JCT IA 14, Marshall, IA

Built 1996 ADT: 195

US 30 WB

Unknown

Over: OAKS AVE

2.5 MILES W OF JCT IA 14, Marshall, IA

Built 1996 ADT: 195

US 30 EB

Unknown

Over: RAMP B TO IA AVE

2.2 MILES E OF JCT IA 330, Marshall, IA

Built 1996 ADT: 750

US 30 WB

Unknown

Over: RAMP B TO IA AVE

2.1 MI. E OF JCT. IA 330, Marshall, IA

Built 1996 ADT: 750

PARKER AVE

Unknown

Over: US 30

1.5 MILES W OF JCT. IA 14, Marshall, IA

Built 1996 ADT: 10,800

GOVERNOR RD

Unknown

Over: RELOC US 30

1.0 MI. E OF JCT. IA 14, Marshall, IA

Built 1995 ADT: 11,900

S 18TH AVE

Unknown

Over: US 30

1.5 MILES E OF JCT IA 14, Marshall, IA

Built 1995 ADT: 10,500

US 30 EB

Unknown

Over: IOWA #146

AT JUNCTION WITH IA 146, Marshall, IA

Built 2002 ADT: 1,505

Showing 551-600 of 20,753 bridges

Related

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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.