Iowa Highlights from FHWA’s
2015 National Bridge Inventory Data:

  • Of the 24,242 bridges in the state, 5,025, or 21%, are classified as structurally deficient. This means one or more ofmthe key bridge elements, such as the deck, superstructure or substructure, is considered to be in “poor” or worse condition.1
  • 1,071 bridges, or 4%, are classified as functionallyobsolete. This means the bridge does not meet design standardsn in line with current practice.
  • Federal investment in Iowa has supported $1.6 billion for capital improvements on 2,088 bridge projects between 2005 and 2014.2
  • Since 2004, 1,970 new bridges have been constructed in the state; 227 have undergone major reconstruction.

Based on % of Structurally Deficient Bridges

Based on # of Structurally Deficient Bridges

Top Most Traveled Structurally Deficient Bridges in the State

CountyYear BuiltDaily CrossingsType of Bridge3Location
Woodbury196235,400Urban InterstateI-29 over Channel Floyd River at 3.5 mi. N of N Jct. US 75
Scott194031,300Urban other principal arterialCentennial Bridge
Woodbury195930,300Urban InterstateI-29 over UP RR & Wall St at 3.0 mi. N of Jct U.S.75
Polk195722,900Urban InterstateSB I-35 over Grand Ave at 1.1 Mi. N Jct. Iowa #5
Polk194221,900Urban other principal arterialIA 415 over NW 66th Ave at 2.1 mi. N of Jct. I-80
Scott196315,400Urban minor arterialN Division St over Duck Creek
Polk193614,400Urban minor arterial2nd Ave over Birdland Dr
Linn193813,700Urban other principal arterial8th Ave over Cedar River
Poweshiek196212,900Urban InterstateEB I-80 over Iowa 146 at Jct.146
Woodbury195912,100Urban InterstateSB I-29 over 8th St at 2.0 mi S of Jct US 20
Black Hawk196911,900Urban minor arterialUniversity Ave over Small Stream at 0
Marshall195111,100Urban minor arterialSo Center St over R.R.And Madison St at 0
Webster195511,000Urban other principal arterialOld US 20 over drainage ditch at 0
Polk195810,800Urban minor arterialE. 30th St. over UP RR at 0
Johnson191510,650Urban other principal arterialNB Ia 1 over Iowa River at 10370
Warren195710,600Rural InterstateNB I-35 over North River at 3.8 Mi. N. of Jct. Ia 92
Warren195710,600Rural InterstateI 35 SB over North River at 3.8 Mi. N of Jct. Ia 92
Linn19809,700Urban collectorEdgewood Rd over US 30 at 2.6 mi W. of Jct. I-380
Cerro Gordo19389,700Urban minor arterial13th St NE over Winnebago River at 0
Cerro Gordo19509,600Urban minor arterial12th St NW over Willow Creek at 0
Warren19579,500Rural InterstateSB I-35 over Middle River at 0.4 mi S of Jct Ia #92
Woodbury19769,200Urban minor arterialExt Military Rd over Big Sioux River at 0
Black Hawk19508,800Urban minor arterialE Ridgeway Ave over Dry Run Creek at City Culvert No. 3C
Linn19008,800Urban collectorMccloud Pl.NE over Mccloud Run at 0
Boone19628,300Urban other principal arterialUS 30 over Honey Creek at 0.7 Mi. W of Jct. SR R23

Bridge Inventory

Type of Bridge3Number of BridgesArea of All Bridges (sq. meters)Daily Crossings on All BridgesNumber of Structurally Deficient BridgesArea of Structurally Deficient Bridges (sq. meters)Daily Crossings on Structurally Deficient Bridges
Rural Interstate374269,6324,367,32032,67330,700
Rural arterial1,243918,7015,020,8901911,35871,060
Rural minor arterial1,060562,2541,930,7103627,19660,380
Rural major collector3,4281,194,3242,458,719539175,045332,205
Rural minor collector3,919953,380546,645770139,86985,770
Rural local road11,9031,732,798619,2853,462378,337147,502
Urban Interstate335662,2407,965,285610,316119,550
Urban freeway/expressway000000
Urban other principal arterial6131,038,5475,629,0501025,727110,220
Urban minor arterial530586,6133,580,7945383,435270,290
Urban collector329186,636832,2193524,16181,180
Urban local road508156,133429,7569240,92146,611
Total24,2428,261,25833,380,6725,025919,0381,355,468

Proposed Bridge Work

Type of WorkNumber of BridgesCost to Repair (in millions)Daily CrossingsArea of Bridges (sq. meters)
Bridge replacement7,744$1.31,499,3801,246,554
Widening & rehabilitation111$1.0135,98434,490
Rehabilitation1,323$0.2740,106351,103
Deck rehabilitation/replacement59$1.065,27529,925
Other structural work5,636$4.52,453,7481,404,446
1 According to the Federal Highway Administration (FHWA), a bridge is classified as structurally deficient if the condition rating for the deck, superstructure, substructure or culvert and retaining walls is rated 4 or below or if the bridge receives an appraisal rating of 2 or less for structural condition or waterway adequacy. During inspections, the condition 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 and the individual element displays signs of advanced section loss, deterioration, spalling or scour.

2 ARTBA analysis of FHWA data, includes all bridge construction-related spending on projects approved by FHWA between 2005 and 2014.

3 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, and the Dwight D. Eisenhower National System of Interstate and Defense Highways. Other principal arterials serve major centers of urban areas or provide mobility through rural areas. Freeways and expressways are similar to interstates, with directional lanes generally separated by a physical barrier, and access/egress points generally limited to on- and off-ramps. Minor arterials are used for trips of moderate length, serve smaller geographic areas and connect to the higher arterial system. 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.

Source: Bridge data is from the 2015 National Bridge Inventory ASCII files, released by the Federal Highway Administration in January 2016. Note that specific conditions on bridges may have changed as a result of recent work.

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