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-397TH ST

Poor

Over: FARM CREEK

073401504, Mills, IA

Built 1959 Load: 18.1 t ADT: 34

FM

Poor

Over: WEST FORK DD

085452701, Monona, IA

Built 1961 Load: 18.1 t ADT: 229

FAWN AVE

Poor

Over: BROKEN KETTLE CREEK

091470804, Plymouth, IA

Built 1953 Load: 18.1 t ADT: 11

FM

Poor

Over: TURKEY CREEK

081251401, Polk, IA

Built 1980 Load: 18.1 t ADT: 50

LOCAL

Poor

Over: BIG BEAR CREEK

080140808, Poweshiek, IA

Built 1951 Load: 18.1 t ADT: 60

LOCAL

Poor

Over: SMALL STREAM

801340, Shelby, IA

Built 1960 Load: 18.1 t ADT: 30

280TH ST

Poor

Over: GRANT 5 OPEN DITCH EXT

082220601, Story, IA

Built 1916 Load: 18.1 t ADT: 131

120TH ST

Poor

Over: EAST BR INDIAN CREEKH

085221801, Story, IA

Built 1919 Load: 18.1 t ADT: 15

150TH ST

Poor

Over: EAST BR INDIAN CREEK

085223401, Story, IA

Built 1950 Load: 18.1 t ADT: 30

560TH AVE

Poor

Over: HAM-STORY 1 OPEN DD

085233102, Story, IA

Built 1924 Load: 18.1 t ADT: 34

170TH STREET

Poor

Over: GRAND RIVER

072280703, Union, IA

Built 1957 Load: 18.1 t ADT: 46

FM

Poor

Over: TRIB DES MOINES RIVER

069102308, Van Buren, IA

Built 1920 Load: 18.1 t ADT: 45

LOCAL

Poor

Over: SMALL STREAM

086272806, Webster, IA

Built 1990 Load: 18.1 t ADT: 30

440TH

Poor

Over: DRAINAGE DITCH

099191701, Worth, IA

Built 1962 Load: 18.1 t ADT: 26

NEWTON AVE

Poor

Over: CROOKED CR

079021706, Cedar, IA

Built 1974 Load: 18.2 t ADT: 15

LOCAL L AVE

Poor

Over: MILL CREEK

093410102, Cherokee, IA

Built 1917 Load: 18.2 t ADT: 15

LOCAL

Poor

Over: STREAM

067261406, Decatur, IA

Built 1988 Load: 18.2 t ADT: 21

LOCAL

Poor

Over: STREAM

081311701, Guthrie, IA

Built 1977 Load: 18.2 t ADT: 20

FF AVE

Poor

Over: DRAINAGE DITCH

081120104, Iowa, IA

Built 1971 Load: 18.2 t ADT: 26

IA 78

Poor

Over: STREAM

3.9 mi. E of Jct. IA 149, Keokuk, IA

Built 1937 Load: 18.2 t ADT: 1,190

FM

Poor

Over: JIM CREEK

077291301, Madison, IA

Built 1931 Load: 18.2 t ADT: 71

LOCAL T-35

Poor

Over: CREEK

071172504, Monroe, IA

Built 1950 Load: 18.2 t ADT: 60

LOCAL

Poor

Over: LITTLE OCHEYDAN RIVER

098400401, Osceola, IA

Built 1949 Load: 18.2 t ADT: 15

FM

Poor

Over: BOONE RIVER

093262003, Wright, IA

Built 1972 Load: 18.2 t ADT: 35

FM

Poor

Over: PRAIRIE CREEK

083121301, Benton, IA

Built 1965 Load: 18.3 t ADT: 1,090

LOCAL

Poor

Over: BEAVER CREEK

084282701, Boone, IA

Built 1920 Load: 18.3 t ADT: 20

LOCAL - 665TH

Poor

Over: JIM BRANCH

076351906, Cass, IA

Built 1978 Load: 18.3 t ADT: 41

FM

Poor

Over: ELK CREEK

069273506, Decatur, IA

Built 1958 Load: 18.3 t ADT: 240

180 TH

Poor

Over: DD #102

084311701, Greene, IA

Built 1978 Load: 18.3 t ADT: 26

LOCAL

Poor

Over: TRIBUTE TO SEELY CREEK

079331304, Guthrie, IA

Built 1988 Load: 18.3 t ADT: 15

S 52ND AVE W

Poor

Over: SMALL STREAM

079202303, Jasper, IA

Built 1947 Load: 18.3 t ADT: 11

FM

Poor

Over: DME RR

074102905, Keokuk, IA

Built 1936 Load: 18.3 t ADT: 200

LOC 80TH AVE

Poor

Over: HINE CREEK

094293202, Kossuth, IA

Built 1987 Load: 18.3 t ADT: 21

LOC 170TH AVE

Poor

Over: PRAIRIE CREEK

095273401, Kossuth, IA

Built 1985 Load: 18.3 t ADT: 5

LOC 80TH AVE

Poor

Over: FOUR MILE CREEK

095292002, Kossuth, IA

Built 1988 Load: 18.3 t ADT: 21

FM 300TH ST

Poor

Over: DD #2 & 36

097272901, Kossuth, IA

Built 1974 Load: 18.3 t ADT: 264

LOCAL ROAD

Poor

Over: HEFFERMAN CREEK

098473301, Lyon, IA

Built 1900 Load: 18.3 t ADT: 46

LOCAL

Poor

Over: DRAINAGE

077150301, Mahaska, IA

Built 1955 Load: 18.3 t ADT: 40

FM

Poor

Over: DEVILS RUN CREEK

085171202, Marshall, IA

Built 1940 Load: 18.3 t ADT: 69

LOCAL

Poor

Over: MUD CREEK

085192808, Marshall, IA

Built 1945 Load: 18.3 t ADT: 11

420TH

Poor

Over: BURR OAK CREEK

099172501, Mitchell, IA

Built 1966 Load: 18.3 t ADT: 15

LOCAL RD

Poor

Over: M NODAWAY RIVER

071361405, Montgomery, IA

Built 1952 Load: 18.3 t ADT: 100

LOCAL

Poor

Over: SO LIZARD CR DD#22

090321502, Pocahontas, IA

Built 1918 Load: 18.3 t ADT: 20

FM

Poor

Over: BIG BEAR CREEK

080132402, Poweshiek, IA

Built 1950 Load: 18.3 t ADT: 50

LOCAL

Poor

Over: WALNUT CREEK

081131801, Poweshiek, IA

Built 1924 Load: 18.3 t ADT: 15

LOCAL

Poor

Over: BOYER RIVER

086371101, Sac, IA

Built 1931 Load: 18.3 t ADT: 15

FM

Poor

Over: CAVITT CREEK

076240204, Warren, IA

Built 1967 Load: 18.3 t ADT: 79

LOCAL

Poor

Over: STREAM

069172304, Appanoose, IA

Built 1998 Load: 18.4 t ADT: 11

LOCAL

Poor

Over: STREAM

083090602, Benton, IA

Built 1970 Load: 18.4 t ADT: 20

LOCAL

Poor

Over: BEAR CK

086101405, Benton, IA

Built 1941 Load: 18.4 t ADT: 40

Showing 17,801-17,850 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.