National Bridge Inventory: Idaho
- The state has identified needed repairs on 1,539 bridges.
- This compares to 1,550 bridges that needed work in 2019.
- Over the life of the IIJA, Idaho will receive a total of $225.0 million in bridge formula funds, which will help make needed repairs.
- Idaho currently has access to $90.0 million of that total, and has committed $92.5 million towards 67 projects as of June 2023.
- Of the 4,588 bridges in the state, 235, or 5.1 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
- This is down from 295 bridges classified as structurally deficient in 2019.
- The deck area of structurally deficient bridges accounts for 3.6 percent of total deck area on all structures.
|County||Year Built||Daily Crossings||Type of Bridge||Location|
|Bannock||1962||17,500||Urban Interstate||I 15 SBL over I 86 WB Ramp|
|Bannock||1962||17,500||Urban Interstate||I 15 SBL over I 86 EB Ramp|
|Bingham||1961||13,000||Rural Interstate||I 15 NBL over I15B;UPRR;S.Blackfoot Ic|
|Bingham||1961||13,000||Rural Interstate||I 15 SBL over I15B;UPRR;S.Blackfoot Ic|
|Canyon||1956||13,000||Urban other principal arterial||Nhs 7773;10th Ave over City St;UPRR;Caldwell Op|
|Bingham||1962||12,000||Urban Interstate||I 15 SBL over US 26;West Blackfoot Ic|
|Twin Falls||1959||10,500||Urban collector||Stc7232;Blue Lakes over Rock Creek|
|Bannock||1962||8,500||Rural Interstate||I 15 SBL over Main Street Gs|
|Bannock||1962||8,500||Rural Interstate||I 15 NBL over I 15B;W.Inkom Ic|
|Bannock||1962||8,500||Rural Interstate||I 15 NBL over Main Street Gs|
|Shoshone||1972||6,900||Rural Interstate||I 90 EBL & WBL over RR Roadbed/No Tracks|
|Bingham||1936||6,600||Urban other principal arterial||I 15B ;US 91 over Blackfoot River|
|Shoshone||1969||6,500||Rural Interstate||I 90 WBL over Elizabeth Park Road Gs|
|Bingham||1936||6,400||Urban minor arterial||SMA 7611;W. Bridge over Snake River|
|Twin Falls||1973||5,600||Urban minor arterial||Stc2714;37 North over Rock Creek|
|Bonner||1962||5,000||Rural arterial||US 2 over Priest River|
|Shoshone||1963||5,000||Rural Interstate||I 90 WBL over Golconda Access Road Ic|
|Oneida||1968||4,900||Rural Interstate||I 84 EBL over Drain|
|Teton||1975||4,000||Rural minor arterial||SH 33 over Spring Creek|
|Bannock||1950||3,900||Urban collector||Stc 7221;Carson St over Portneuf River|
|Bingham||1923||3,800||Rural arterial||US 91 over Gibson Lateral Canal|
|Valley||1933||3,600||Rural arterial||SH 55 over UPRR;N.Fk.Payette River|
|Payette||1953||3,400||Urban minor arterial||SH 52 over Snake River;Payette Br.|
|Bingham||1951||3,400||Rural minor arterial||US 91 over Blackfoot Canal|
|Bannock||1969||3,300||Urban collector||Stc7151;Benton St over Portneuf River|
|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||251||144,847||590,430||6||1,671||13,300|
|Rural major collector||766||267,071||856,022||30||15,714||22,608|
|Rural minor collector||225||48,361||88,550||14||3,791||3,475|
|Rural local road||2,092||294,019||311,606||152||19,346||15,854|
|Urban other principal arterial||188||254,754||3,080,014||2||4,153||19,600|
|Urban minor arterial||146||101,464||1,571,050||4||4,282||18,400|
|Urban local road||109||35,730||129,568||4||759||2,670|
|Type of Work||Number of Bridges||Cost to Repair
|Daily Crossings||Area of Bridges
|Widening & rehabilitation||27||$30||78,575||14,420|
|Other structural work||20||$27||88,635||11,347|
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 32 in 2022
in the nation in % of structurally deficient bridges
Compared to 39 in 2022
in the nation in # of structurally deficient bridges
Compared to 34 in 2022
in the nation in % of structurally deficient bridge deck area