National Bridge Inventory: Michigan

  • Of the 11,271 bridges in the state, 1,219, or 10.8 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is up from 1,202 bridges classified as structurally deficient in 2016.
  • The deck area of structurally deficient bridges accounts for 7.5 percent of total deck area on all structures.
  • 72 of the structurally deficient bridges are on the Interstate Highway System. A total of 83.9 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.
  • 1,213 bridges are posted for load, which may restrict the size and weight of vehicles crossing the structure.
  • The state has identified needed repairs on 2,667 bridges at an estimated cost of $2.5 billion.
  • This compares to 2,651 bridges that needed work in 2016.

County Year Built Daily Crossings Type of Bridge Location
Wayne 1967 103,925 Urban Interstate I-75 over Fort St
Wayne 1971 98,506 Urban Interstate I-94 over Ent to Ford Plant
Macomb 1955 82,735 Urban other principal arterial Mound Rd over Sharkey Drain
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
Genesee 1957 70,414 Urban Interstate I-75 over Court St
Kalamazoo 1956 69,260 Urban Interstate I-94 over Portage Road
Oakland 1964 65,985 Urban Interstate I-75 SB over M-150 (Rochester Rd.)
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 and Ramp B over Chavez Dr
Genesee 1976 63,400 Urban Interstate I-475 over Davison - Broadway Aves
Wayne 1969 60,400 Urban other principal arterial M-102 8 mile Rd over I-75
Saginaw 1961 60,342 Urban Interstate I-75 over CSX RR
Wayne 1962 60,077 Urban Interstate I-94 EB over Beech-Daly Rd
Genesee 1971 59,000 Urban Interstate I-475 over CSX RR & NB Serv Rd(Abn)
Kalamazoo 1954 58,174 Urban Interstate I-94 over Norfolk Southern
Kent 1963 57,075 Urban Interstate I-196, M-21 WB over Conrail (No Tracks)(Abn)
Wayne 1962 55,956 Urban Interstate I-94 WB over Wayne Rd
Wayne 1953 54,800 Urban Interstate I-94EB Rmp to M-10 over I-94 WB & M-10 SB
Jackson 1949 54,000 Urban local road Elm Rd over I-94
Oakland 1964 52,934 Urban Interstate I-75 SB over Coolidge Rd
Kent 1961 50,972 Urban Interstate I-296 (US-131) SB over US-131 Br (Leonard)
Kent 1962 47,650 Urban Interstate I-296 WB/US-131 SB over Ann Street
Livingston 1962 44,600 Urban Interstate I-96 WB over Grand River Ave
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 403 368,428 7,934,575 16 9,922 297,194
Rural arterial 641 412,793 5,703,469 33 15,501 273,395
Rural minor arterial 623 294,861 3,159,599 49 22,451 194,352
Rural major collector 2,096 690,117 4,418,165 248 60,344 524,402
Rural minor collector 541 138,556 1,082,073 57 9,738 31,376
Rural local road 3,173 563,924 1,551,224 460 51,751 124,372
Urban Interstate 837 1,407,949 30,280,644 56 87,965 2,007,386
Urban freeway/expressway 320 337,818 8,377,680 16 14,217 364,691
Urban other principal arterial 711 883,186 15,557,213 67 80,270 1,295,587
Urban minor arterial 825 753,292 9,607,549 106 81,161 1,171,845
Urban collector 485 292,606 3,256,738 45 28,601 227,619
Urban local road 616 330,287 2,943,800 66 23,632 187,973
Total 11,271 6,473,817 93,872,729 1,219 485,554 6,700,192
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 665 $362 1,983,113 147,677
Widening & rehabilitation 77 $73 1,306,372 44,445
Rehabilitation 989 $678 5,543,623 407,953
Deck rehabilitation/replacement 767 $1,238 9,508,007 749,615
Other structural work 169 $143 651,633 85,795
Total 2,667 $2,495 18,992,748 1,435,485

About the data:

Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on March 11, 2021. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections. Cost estimates were downloaded by ARTBA on March 11, 2021.

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 2019 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 11 in 2019

in the nation in % of structurally deficient bridges

1. West Virginia 21.2%
8. Puerto Rico 12.1%
9. Michigan 10.8%
10. North Dakota 10.3%

Compared to 16 in 2019

in the nation in # of structurally deficient bridges

1. Iowa 4,571
14. Nebraska 1,302
15. Michigan 1,219
16. Indiana 1,111

Compared to 10 in 2019

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 21.0%
14. Maine 8.0%
15. Michigan 8.0%
16. Connecticut 8.0%
Full State Ranking


  • Source: Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on March 11, 2021. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

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