National Bridge Inventory: Michigan
- Of the 11,228 bridges in the state, 1,196, or 10.7 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
- This is down from 1,251 bridges classified as structurally deficient in 2014.
- 62 of the structurally deficient bridges are on the Interstate Highway System.
- 1,206 bridges are posted for load, which may restrict the size and weight of vehicles crossing the structure.
- The state has identified needed repairs on 2,627 bridges at an estimated cost of $1.7 billion.
- This compares to 2,749 bridges that needed work in 2014.
|County||Year Built||Daily Crossings||Type of Bridge||Location|
|Wayne||1954||146,000||Urban minor arterial||Second Blvd over I-94|
|Wayne||1963||114,656||Urban freeway/expressway||M-39 over Rouge River|
|Wayne||1967||100,492||Urban Interstate||I-75 over Rouge R,Dearborn St & RR|
|Wayne||1967||100,492||Urban Interstate||I-75 over Fort St|
|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)|
|Kalamazoo||1956||69,260||Urban Interstate||I-94 over Portage Road|
|Oakland||1964||67,700||Urban freeway/expressway||M-39 (Ramp H) over M-10 WB (Ramp G)|
|Oakland||1964||65,985||Urban Interstate||I-75 SB over M-150 (Rochester Rd.)|
|Wayne||1962||65,737||Urban Interstate||I-94 WB over Ecorse Rd|
|Jackson||1949||64,800||Urban Interstate||I-94 over Conrail & Grand River|
|Wayne||1953||64,700||Urban freeway/expressway||M-10 EB over I-94 Ramp|
|Wayne||1967||63,820||Urban other principal arterial||US-24 Telegraph Rd over Rouge River|
|Genesee||1976||63,400||Urban Interstate||I-475 over Stever - 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||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|
|Wayne||1964||51,090||Urban Interstate||I-75 NB over Blakely Drain|
|Wayne||1964||51,090||Urban Interstate||I-75 SB over Blakely Drain|
|Wayne||1966||50,643||Urban Interstate||I-75 SB over North Line Rd|
|Wayne||1966||47,466||Urban Interstate||I-75 NB over Eureka Rd|
|Wayne||1966||47,466||Urban Interstate||I-75 SB over Eureka Rd|
|Livingston||1962||44,600||Urban Interstate||I-96 EB over Grand River Ave|
|Type of Bridge||Number of Bridges||Area of All Bridges
|Daily Crossings on All Bridges||Number of Structurally Deficient Bridges||Area of Structurally Deficient Bridges
|Daily Crossings on Structurally Deficient Bridges|
|Rural minor arterial||618||298,832||3,175,058||46||21,013||182,163|
|Rural major collector||2,089||686,665||4,417,648||260||61,576||494,383|
|Rural minor collector||543||138,372||1,094,013||57||9,353||29,227|
|Rural local road||3,164||559,808||1,539,868||465||54,168||126,484|
|Urban other principal arterial||713||879,390||15,617,613||67||99,711||1,429,972|
|Urban minor arterial||821||748,942||9,726,645||103||72,675||1,308,193|
|Urban local road||611||331,607||2,950,940||60||22,762||190,440|
|Type of Work||Number of Bridges||Cost to Repair
|Daily Crossings||Area of Bridges
|Widening & rehabilitation||77||$53||1,306,418||44,043|
|Other structural work||166||$56||650,720||84,617|
About the data:
Data from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), released March 15, 2019. 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 2017 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 cost estimate is supplied by the bridge owner or the bridge is classified as structurally deficient.
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.
from 12 in 2017
in the nation in % of structurally deficient bridges
from 16 in 2017
in the nation in # of structurally deficient bridges