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

540TH ST

Good

Over: BROOKS CREEK

091370601, Buena Vista, IA

Built 2015 Load: 35.6 t ADT: 30

LOCAL

Good

Over: PURGATORY CREEK

087321401, Calhoun, IA

Built 1990 Load: 35.6 t ADT: 5

FM

Good

Over: NEDDEMEYER CREEK

083401601, Crawford, IA

Built 2005 Load: 35.6 t ADT: 40

LOC SHERWOOD RD

Good

Over: PLUM CREEK

088032004, Delaware, IA

Built 1993 Load: 35.6 t ADT: 49

LOC QUARTER RD

Good

Over: MAQUOKETA RIVER

088043404, Delaware, IA

Built 1996 Load: 35.6 t ADT: 49

SB NW ARTERIAL

Good

Over: OVER CC RR & CATFISH CK

0.2 MI. N OF JCT. US 20, Dubuque, IA

Built 1997 Load: 35.6 t ADT: 4,696

US 61 OFF RAMP

Good

Over: GRANGER CREEK

US 61 CONNECTOR, Dubuque, IA

Built 2019 Load: 35.6 t ADT: 756

G AVE.

Good

Over: BEAR CREEK

092081204, Fayette, IA

Built 1980 Load: 35.6 t ADT: 206

FM RAVEN AVE

Good

Over: OTTER CREEK

092202402, Franklin, IA

Built 1983 Load: 35.6 t ADT: 59

NB I-29

Good

Over: PLUM CREEK

0.5 mi. S of Jct. SR J24, Fremont, IA

Built 2009 Load: 35.6 t ADT: 6,100

EB US 20 RAMP B

Good

Over: STREAM

0.1 MILE W OF JCT SR T55, Grundy, IA

Built 2000 Load: 35.6 t ADT: 270

LOCAL

Good

Over: PRAIRIE CR

087260503, Hamilton, IA

Built 2008 Load: 35.6 t ADT: 20

FM

Good

Over: WOLF CREEK

071070802, Henry, IA

Built 1984 Load: 35.6 t ADT: 120

LOCAL

Good

Over: ODEBOLT CREEK

087392304, Ida, IA

Built 2003 Load: 35.6 t ADT: 35

S 52ND AVE W

Good

Over: RED ROCK CREEK

079212301, Jasper, IA

Built 2012 Load: 35.6 t ADT: 16

FM

Good

Over: MUD CREEK

081211201, Jasper, IA

Built 2001 Load: 35.6 t ADT: 80

FM

Good

Over: OVER IAIS RR

079052704, Johnson, IA

Built 1993 Load: 35.6 t ADT: 820

FM

Good

Over: STREAM

077102312, Keokuk, IA

Built 1992 Load: 35.6 t ADT: 40

FM

Good

Over: SUGAR CREEK

066060304, Lee, IA

Built 2003 Load: 35.6 t ADT: 80

LEFEBURE RD

Good

Over: TRIB TO PRAIRIE CREEK

082081506, Linn, IA

Built 2022 Load: 35.6 t ADT: 648

EB COLL IA 100

Good

Over: OVER CC RR & BIKE PATH

0.1 MI. S OF JCT. IA 100, Linn, IA

Built 1982 Load: 35.6 t ADT: 2,140

NB US 151

Good

Over: BIG CREEK

4.7 mi. N of Jct. IA 13, Linn, IA

Built 1992 Load: 35.6 t ADT: 7,000

WB/NB IA 163

Good

Over: OVER UP RR

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

Built 1997 Load: 35.6 t ADT: 3,900

190TH ST

Good

Over: STREAM

072432902, Mills, IA

Built 2018 Load: 35.6 t ADT: 131

LOCAL ROAD

Good

Over: BRANCH OF TARKIO CREEK

072373410, Montgomery, IA

Built 2003 Load: 35.6 t ADT: 1,404

LOCAL

Good

Over: FLOYD RIVER

097401901, O'Brien, IA

Built 2008 Load: 35.6 t ADT: 35

IA 60 NB

Good

Over: OTTER CREEK

1.6 mi. S of SR A34, Osceola, IA

Built 2004 Load: 35.6 t ADT: 2,700

IA 60 SB

Good

Over: OTTER CREEK

1.6 mi. S of SR A34, Osceola, IA

Built 2003 Load: 35.6 t ADT: 2,700

320TH ST

Good

Over: W BR PERRY CREEK

090472803, Plymouth, IA

Built 2001 Load: 35.6 t ADT: 60

FOX AVE

Good

Over: PERRY CREEK

090473308, Plymouth, IA

Built 1983 Load: 35.6 t ADT: 170

ECHO ROAD

Good

Over: BROKEN KETTLE CREEK

091481403, Plymouth, IA

Built 1996 Load: 35.6 t ADT: 26

N 33 150TH AVE

Good

Over: BR BIG CEDAR CREEK

090343602, Pocahontas, IA

Built 2019 Load: 35.6 t ADT: 15

500TH ST

Good

Over: LITTLE CEDAR CREEK

092343001, Pocahontas, IA

Built 2021 Load: 35.6 t ADT: 15

FM

Good

Over: MUD CREEK

078222201, Polk, IA

Built 1990 Load: 35.6 t ADT: 358

FM

Good

Over: SAYLOR CREEK

079240338, Polk, IA

Built 2003 Load: 35.6 t ADT: 3,835

FM

Good

Over: PONY CREEK

074432904, Pottawattamie, IA

Built 1981 Load: 35.6 t ADT: 100

330TH STREET

Good

Over: MIDDLE SILVER CREEK

075410302, Pottawattamie, IA

Built 2002 Load: 35.6 t ADT: 110

97TH AVE

Good

Over: CREEK

079E20304, Scott, IA

Built 2016 Load: 35.6 t ADT: 26

RIVER CAMP RD

Good

Over: MUD CREEK

080E21403, Scott, IA

Built 1998 Load: 35.6 t ADT: 290

FM

Good

Over: SILVER CREEK

078403407, Shelby, IA

Built 1980 Load: 35.6 t ADT: 71

LOCAL

Good

Over: W NISHNABOTNA RIVER

081372103, Shelby, IA

Built 1994 Load: 35.6 t ADT: 41

US 18

Good

Over: ROCK RIVER

0.3 mi. W of Jct SR K24, Sioux, IA

Built 2002 Load: 35.6 t ADT: 3,040

330TH ST

Good

Over: MUD CREEK

on 330th st ov Wolf Creek, Story, IA

Built 2021 Load: 35.6 t ADT: 15

190TH ST/E29

Good

Over: EAST BR INDIAN CREEK

084222401, Story, IA

Built 1963 Load: 35.6 t ADT: 669

IRR-FM

Good

Over: DEER CREEK

083152809, Tama, IA

Built 1980 Load: 35.6 t ADT: 874

FM

Good

Over: EAST 102 RIVER

067343005, Taylor, IA

Built 1993 Load: 35.6 t ADT: 71

FM

Good

Over: NODAWAY RIVER DITCH

070353105, Taylor, IA

Built 1989 Load: 35.6 t ADT: 40

LOCAL

Good

Over: LIZARD CREEK

090303402, Webster, IA

Built 2004 Load: 35.6 t ADT: 30

A34 (420TH ST)

Good

Over: PIKE RUN CREEK

0.5 mi. E. of HWY 9, Winnebago, IA

Built 2014 Load: 35.6 t ADT: 100

LOCAL ROAD

Good

Over: CREEK

097080101, Winneshiek, IA

Built 1991 Load: 35.6 t ADT: 59

Showing 12,951-13,000 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.