National Bridge Inventory: Iowa

  • The state has identified needed repairs on 14,905 bridges.
  • This compares to 15,223 bridges that needed work in 2019.
  • Over the life of the IIJA, Iowa will receive a total of $467.1 million in bridge formula funds, which will help make needed repairs.
  • Iowa currently has access to $186.8 million of that total, and has committed $29.8 million towards 39 projects as of June 2023.
  • Of the 23,720 bridges in the state, 4,558, or 19.2 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is down from 4,575 bridges classified as structurally deficient in 2019.
  • The deck area of structurally deficient bridges accounts for 10.1 percent of total deck area on all structures.

County Year Built Daily Crossings Type of Bridge Location
Scott 1940 29,800 Urban other principal arterial Centennial Bridge
Scott 1970 23,900 Urban Interstate I-280 over Mississippi River & Road
Polk 1936 17,535 Urban minor arterial 2nd Ave over Birdland Dr
Polk 1935 17,535 Urban minor arterial 2nd Ave over Des Moines River
Scott 1900 15,300 Urban minor arterial Eastern Ave over Duck Creek
Polk 1967 14,122 Urban minor arterial Sw 9th St over Cherry, RR, Mlk Pkwy
Johnson 1972 14,039 Urban minor arterial Gilbert St over Ralston Creek
Poweshiek 1963 13,450 Rural Interstate I 80 WB over Iowa 21
Poweshiek 1962 11,100 Urban Interstate EB I 80 over Iowa 146
Lee 1915 10,964 Urban minor arterial Ave L over Dry Creek
Linn 1988 10,800 Urban minor arterial 8th Ave over Indian Creek
Marshall 1951 10,458 Urban minor arterial So Center St over Linn Creek
Johnson 1915 10,400 Urban other principal arterial Ia 1 NB over Iowa River
Linn 1969 10,278 Urban other principal arterial Edgewood Rd NE over Cedar River & RR
Scott 1978 10,200 Urban minor arterial Eastern Ave over Goose Creek
Webster 1968 9,860 Urban minor arterial 1St Ave S over 21St St & RR
Marshall 1951 9,500 Urban minor arterial So Center St over RR and Madison St
Linn 1938 9,391 Urban other principal arterial 8th Ave over Cedar River
Woodbury 1962 8,957 Urban minor arterial 6th St over Floyd River
Webster 1955 8,903 Urban other principal arterial 5th Ave over drainage Ditch
Webster 1974 8,807 Urban minor arterial N 15th St over Soldier Creek
Black Hawk 1950 8,400 Urban minor arterial E Ridgeway Ave over Dry Run Creek
Benton 1950 7,600 Rural arterial US 30 over Prairie Creek
Floyd 1914 6,900 Urban minor arterial Gilbert St over Shermans Creek
Polk 1967 6,882 Urban minor arterial Sw 8th St over RR, Cherry, Mlk Jr Pkwy
Type of Bridge Number of Bridges Area of All Bridges
(sq. meters)
Daily Crossings on All Bridges Number of Structurally Deficient Bridges Area of Structurally Deficient Bridges
(sq. meters)
Daily Crossings on Structurally Deficient Bridges
Rural Interstate 377 379,884 5,111,860 1 648 13,450
Rural arterial 1,273 1,029,882 5,681,607 6 3,782 20,580
Rural minor arterial 1,068 610,510 2,014,429 15 8,348 25,434
Rural major collector 3,420 1,271,628 2,572,999 654 240,107 436,880
Rural minor collector 3,850 1,003,648 552,145 730 149,178 87,706
Rural local road 11,359 1,837,644 612,931 2,978 335,901 129,747
Urban Interstate 338 722,537 7,991,500 4 35,060 47,100
Urban freeway/expressway 0 0 0 0 0 0
Urban other principal arterial 644 1,136,452 5,689,639 5 27,941 68,772
Urban minor arterial 557 628,706 3,272,466 48 66,653 303,465
Urban collector 322 196,493 824,494 33 18,266 55,936
Urban local road 512 158,159 414,973 84 17,516 51,233
Total 23,720 8,975,543 34,739,043 4,558 903,401 1,240,303
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 6,616 $1,810 1,467,476 1,196,064
Widening & rehabilitation 56 $28 107,189 27,449
Rehabilitation 1,105 $412 829,113 392,736
Deck rehabilitation/replacement 40 $21 37,196 20,069
Other structural work 7,088 $1,920 2,771,595 1,868,800
Total 14,905 $4,191 5,212,569 3,505,119

About the data:

Data and cost estimates are from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on July 3, 2023. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

Effective January 1, 2018, FHWA changed the definition of structurally deficient as part of the final rule on highway and bridge performance measures, published May 20, 2017 pursuant to the 2012 federal aid highway bill Moving Ahead for Progress in the 21st Century Act (MAP-21). Two measures that were previously used to classify bridges as structurally deficient are no longer used. This includes bridges where the overall structural evaluation was rated in poor or worse condition, or where the adequacy of waterway openings was insufficient.

The new definition limits the classification to bridges where one of the key structural elements—the deck, superstructure, substructure or culverts, are rated in poor or worse condition. During inspection, the conditions of a variety of bridge elements are rated on a scale of 0 (failed condition) to 9 (excellent condition). A rating of 4 is considered “poor” condition.

Cost estimates have been derived by ARTBA, based on 2022 average bridge replacement costs for structures on and off the National Highway System, published by FHWA. Bridge rehabilitation costs are estimated to be 68 percent of replacement costs. A bridge is considered to need repair if the structure has identified repairs as part of the NBI, a repair cost estimate is supplied by the bridge owner or the bridge is classified as structurally deficient. Please note that for a few states, the number of bridges needing to be repaired can vary significantly from year to year, and reflects the data entered by the state.

Bridges are classified by FHWA into types based on the functional classification of the roadway on the bridge. Interstates comprise routes officially designated by the Secretary of Transportation. Other principal arterials serve major centers of urban areas or provide mobility through rural areas. Freeways and expressways have directional lanes generally separated by a physical barrier, and access/egress points generally limited to on- and off-ramps. Minor arterials serve smaller areas and are used for trips of moderate length. Collectors funnel traffic from local roads to the arterial network; major collectors have higher speed limits and traffic volumes and are longer in length and spaced at greater intervals, while minor collectors are shorter and provide service to smaller communities. Local roads do not carry through traffic and are intended for short distance travel.

Compared to 2 in 2022

in the nation in % of structurally deficient bridges

1. West Virginia 20.0%
2. Iowa 19.0%
3. South Dakota 17.0%

Compared to 1 in 2022

in the nation in # of structurally deficient bridges

1. Iowa 4,558
2. Pennsylvania 3,022

Compared to 7 in 2022

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 15.0%
7. Iowa 10.0%
8. Puerto Rico 10.0%
Full State Ranking


  • Source: Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on July 3, 2023. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

    ARTBA is a non-partisan federation whose primary goal is to aggressively grow and protect transportation infrastructure investment to meet the public and business demand for safe and efficient travel.

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