National Bridge Inventory: Michigan

  • Of the 11,314 bridges in the state, 1,269, or 11.2 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is up from 1,196 bridges classified as structurally deficient in 2018.
  • The deck area of structurally deficient bridges accounts for 7.9 percent of total deck area on all structures.
  • 77 of the structurally deficient bridges are on the Interstate Highway System. A total of 83.4 percent of the structurally deficient bridges are not on the National Highway System, which includes the Interstate and other key roads linking major airports, ports, rail and truck terminals.
  • 1,255 bridges are posted for load, which may restrict the size and weight of vehicles crossing the structure.
  • The state has identified needed repairs on 2,701 bridges at an estimated cost of $3.4 billion.
  • This compares to 2,627 bridges that needed work in 2018.

County Year Built Daily Crossings Type of Bridge Location
Oakland 1971 209,200 Urban Interstate I-696 over I-75 & 4 Ramps
Wayne 1967 103,925 Urban Interstate I-75 over Fort St
Wayne 1971 98,506 Urban Interstate I-94 over Ent to Ford Plant
Wayne 1970 78,863 Urban Interstate I-96 WB Main Rdwy over M-39 (Southfield Expr)
Wayne 1962 74,175 Urban Interstate I-94 WB over Ecorse Rd
Kalamazoo 1956 69,260 Urban Interstate I-94 over Portage Road
Kalamazoo 1954 67,300 Urban Interstate I-94 over Norfolk Southern
Wayne 1971 65,653 Urban Interstate I-275 SB over Schoolcraft Rd
Wayne 1953 64,700 Urban freeway/expressway M-10 EB over I-94 Ramp
Genesee 1976 63,400 Urban Interstate I-475 over Gilkey Creek
Genesee 1976 63,400 Urban Interstate I-475 over Davison - Broadway Aves
Genesee 1976 63,400 Urban Interstate I-475 and Ramp B over Chavez Dr
Wayne 1953 63,154 Urban freeway/expressway M-10 WB over I-94 Ramp from M-10
Livingston 1960 61,696 Rural arterial US-23 over M-36
Wayne 1969 60,400 Urban other principal arterial M-102 8 mile Rd over I-75
Wayne 1962 60,077 Urban Interstate I-94 EB over Beech-Daly Rd
Wayne 1955 59,083 Urban Interstate I-94 EB over I-94 Ramp to M-10
Genesee 1971 59,000 Urban Interstate I-475 over CSX RR & NB Serv Rd(Abn)
Jackson 1949 54,000 Urban local road Elm Rd over I-94
Kent 1961 50,972 Urban Interstate I-296 (US-131) SB over US-131 Br (Leonard)
Livingston 1962 44,600 Urban Interstate I-96 EB over Grand River Ave
Livingston 1962 44,600 Urban Interstate I-96 WB over Grand River Ave
Kent 1961 42,978 Urban other principal arterial M-44 (E Belt Line) over I-96
Wayne 1962 42,800 Urban minor arterial Jefferson Ave over I-375
Kent 1964 41,000 Urban Interstate I-196 WB over Gd R,I-296,Scrb,Trn,Monr
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 405 370,103 8,103,855 21 13,148 252,670
Rural arterial 645 414,109 5,736,972 35 19,916 343,390
Rural minor arterial 632 299,448 3,207,694 58 26,356 201,125
Rural major collector 2,106 695,000 4,469,137 262 66,932 534,641
Rural minor collector 544 139,178 1,078,793 57 8,815 39,801
Rural local road 3,186 565,255 1,550,509 485 53,865 137,432
Urban Interstate 842 1,417,483 30,785,224 56 103,355 1,974,522
Urban freeway/expressway 319 337,407 8,357,669 23 17,392 618,867
Urban other principal arterial 733 901,636 15,815,936 65 81,082 1,250,455
Urban minor arterial 825 754,517 9,566,612 98 79,699 1,032,008
Urban collector 489 298,666 3,413,716 42 26,149 220,079
Urban local road 588 301,385 2,490,268 67 19,569 187,349
Total 11,314 6,494,187 94,576,385 1,269 516,278 6,792,339
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 668 $474 1,998,137 149,632
Widening & rehabilitation 75 $102 1,309,573 43,831
Rehabilitation 1,033 $927 5,270,339 420,240
Deck rehabilitation/replacement 764 $1,707 9,494,697 748,484
Other structural work 161 $166 623,056 75,700
Total 2,701 $3,375 18,695,802 1,437,886

About the data:

Data and cost estimates are from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on February 1, 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 2021 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 10 in 2021

in the nation in % of structurally deficient bridges

1. West Virginia 20.0%
8. Louisiana 12.0%
9. Michigan 11.0%
10. North Dakota 11.0%

Compared to 14 in 2021

in the nation in # of structurally deficient bridges

1. Iowa 4,604
11. Kansas 1,294
12. Michigan 1,269
13. Ohio 1,223

Compared to 13 in 2021

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 17.0%
10. Missouri 8.0%
11. Michigan 8.0%
12. Washington 8.0%
Full State Ranking


  • Source: Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on February 1, 2023. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

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