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

FM

Fair

Over: MIDDLE WALNUT

073092004, Jefferson, IA

Built 1975 Load: 21.0 t ADT: 40

IA 182

Fair

Over: STREAM

2.5 mi. S of Jct. IA 9, Lyon, IA

Built 1955 Load: 21.0 t ADT: 2,500

FM

Fair

Over: HEFFERMAN CREEK

098473402, Lyon, IA

Built 1978 Load: 21.0 t ADT: 60

LOCAL

Fair

Over: MUD CREEK

100473601, Lyon, IA

Built 1963 Load: 21.0 t ADT: 112

LOCAL

Fair

Over: JONES CREEK

075272808, Madison, IA

Built 1985 Load: 21.0 t ADT: 71

LOCAL

Fair

Over: HOWERDON CREEK

076282004, Madison, IA

Built 1978 Load: 21.0 t ADT: 29

FM

Fair

Over: BLUFF CREEK

074172602, Mahaska, IA

Built 1970 Load: 21.0 t ADT: 60

IA 14

Fair

Over: BRUSH CREEK

0.2 MI. S OF S.R. G28, Marion, IA

Built 1965 Load: 21.0 t ADT: 3,820

FM

Fair

Over: PRAIRE CREEK

077201701, Marion, IA

Built 1968 Load: 21.0 t ADT: 70

FM

Fair

Over: RAVEN CREEK

082171201, Marshall, IA

Built 1978 Load: 21.0 t ADT: 98

LOCAL

Fair

Over: NORTH TIMBER CREEK

083182203, Marshall, IA

Built 1979 Load: 21.0 t ADT: 113

FM

Fair

Over: NORTH TIMBER CREEK

083192204, Marshall, IA

Built 1984 Load: 21.0 t ADT: 49

FM

Fair

Over: LITTLE TARKIO

071381201, Montgomery, IA

Built 1959 Load: 21.0 t ADT: 71

LOCAL

Fair

Over: RAMA CREEK

071383106, Montgomery, IA

Built 1972 Load: 21.0 t ADT: 20

FM

Fair

Over: NISHNABOTNA TRIB

071392406, Montgomery, IA

Built 1968 Load: 21.0 t ADT: 41

LOCAL

Fair

Over: LOCAL CK

072361102, Montgomery, IA

Built 1979 Load: 21.0 t ADT: 20

LOCAL

Fair

Over: TARKIO CREEK

072370901, Montgomery, IA

Built 1971 Load: 21.0 t ADT: 89

LOCAL

Fair

Over: CRABAPPLE CREEK

072390303, Montgomery, IA

Built 1984 Load: 21.0 t ADT: 29

LOCAL

Fair

Over: CRABAPPLE CREEK

072391001, Montgomery, IA

Built 1968 Load: 21.0 t ADT: 20

LOCAL

Fair

Over: CRABAPPLE CREEK

072391501, Montgomery, IA

Built 1979 Load: 21.0 t ADT: 11

LOCAL

Fair

Over: SIN CR

073362602, Montgomery, IA

Built 1974 Load: 21.0 t ADT: 20

LOCAL

Fair

Over: SEVEN MILE CREEK

073362907, Montgomery, IA

Built 1972 Load: 21.0 t ADT: 29

FM

Fair

Over: TARKIO CREEK

073373405, Montgomery, IA

Built 1957 Load: 21.0 t ADT: 15

LOCAL

Fair

Over: NISHNABOTNA TRIB

073382508, Montgomery, IA

Built 1974 Load: 21.0 t ADT: 79

LOCAL

Fair

Over: CRABAPPLE CREEK

073392301, Montgomery, IA

Built 1968 Load: 21.0 t ADT: 29

LOCAL

Fair

Over: INDIAN CREEK TRIB

073392801, Montgomery, IA

Built 1971 Load: 21.0 t ADT: 26

NATURE AVE

Fair

Over: PLYMOUTH CREEK

092453602, Plymouth, IA

Built 1900 Load: 21.0 t ADT: 100

320TH STREET

Fair

Over: STREAM

076410904, Pottawattamie, IA

Built 1976 Load: 21.0 t ADT: 20

SUMAC ROAD

Fair

Over: MIDDLE SILVER CREEK

077403101, Pottawattamie, IA

Built 1979 Load: 21.0 t ADT: 50

ALLERS GROVE RD

Fair

Over: CREEK

079E20206, Scott, IA

Built 1938 Load: 21.0 t ADT: 120

LOCAL ROAD

Fair

Over: PAPOOSE CREEK

074240904, Warren, IA

Built 1970 Load: 21.0 t ADT: 30

LOCAL ROAD

Fair

Over: BROADHORN CREEK

074250801, Warren, IA

Built 1972 Load: 21.0 t ADT: 26

LOCAL ROAD

Fair

Over: BROADHORN CREEK

074250901, Warren, IA

Built 1977 Load: 21.0 t ADT: 30

FM

Fair

Over: COAL CREEK

075220402, Warren, IA

Built 1970 Load: 21.0 t ADT: 60

LOCAL ROAD

Fair

Over: COAL CREEK

076223403, Warren, IA

Built 1972 Load: 21.0 t ADT: 41

LOCAL

Fair

Over: LITTLE MUDDY CREEK

067231503, Wayne, IA

Built 1984 Load: 21.0 t ADT: 20

LOCAL

Fair

Over: JACKSON CREEK

069212504, Wayne, IA

Built 1985 Load: 21.0 t ADT: 11

LOCAL

Fair

Over: JACKSON CREEK

069213502, Wayne, IA

Built 1984 Load: 21.0 t ADT: 26

LOCAL ROAD

Fair

Over: SILVER CREEK

099090101, Winneshiek, IA

Built 1969 Load: 21.0 t ADT: 39

US 30

Fair

Over: NOAH CREEK

AT JUNCTION WITH SR R18, Boone, IA

Built 1962 Load: 21.1 t ADT: 8,800

LOC 100TH ST

Fair

Over: STREAM

090070501, Buchanan, IA

Built 1940 Load: 21.1 t ADT: 44

LOCAL

Fair

Over: FIELD STREAM

082340303, Carroll, IA

Built 1960 Load: 21.1 t ADT: 29

FM

Fair

Over: WEST ROCK CREEK

081030302, Cedar, IA

Built 1974 Load: 21.1 t ADT: 60

HERON AVE

Fair

Over: DRY MILL CREEK

093040406, Clayton, IA

Built 1960 Load: 21.1 t ADT: 82

LOCAL

Fair

Over: STREAM

068243402, Decatur, IA

Built 2002 Load: 21.1 t ADT: 15

ENTRANCE

Fair

Over: SIDE DITCH

089010403, Dubuque, IA

Built 2017 Load: 21.1 t ADT: 10

FM

Fair

Over: GIZZARD CREEK

095152301, Floyd, IA

Built 1958 Load: 21.1 t ADT: 678

LOCAL

Fair

Over: DD

092301303, Humboldt, IA

Built 1955 Load: 21.1 t ADT: 11

FM

Fair

Over: INDIAN CREEK TRIB

073393301, Montgomery, IA

Built 1957 Load: 21.1 t ADT: 26

LOCAL

Fair

Over: SO BR LITTLE FLOYD RIVER

096411102, O'Brien, IA

Built 1937 Load: 21.1 t ADT: 30

Showing 2,851-2,900 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.