National Bridge Inventory: Delaware

  • Of the 872 bridges in the state, 14, or 1.6 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is down from 34 bridges classified as structurally deficient in 2018.
  • The deck area of structurally deficient bridges accounts for 2.7 percent of total deck area on all structures.
  • 0 of the structurally deficient bridges are on the Interstate Highway System. A total of 92.9 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.
  • 22 bridges are posted for load, which may restrict the size and weight of vehicles crossing the structure.
  • The state has identified needed repairs on 317 bridges at an estimated cost of $1.8 billion.
  • This compares to 342 bridges that needed work in 2018.

County Year Built Daily Crossings Type of Bridge Location
New Castle 1971 18,195 Urban minor arterial Red Mill Rd over stream Mill Pond
Kent 1941 10,208 Rural arterial US Route 13 over C & D Canal
New Castle 1963 9,740 Urban minor arterial Chapman Rd over I 95, Delaware Turnpike
Sussex 1957 7,769 Rural major collector SR 54 over Assawoman Bay
Kent 1965 7,685 Urban collector Lebanon Rd/SR10 WB over St. Jones River
New Castle 1920 7,525 Rural minor arterial Dupont Pkw/US13 SB over Blackbird Creek
New Castle 1981 4,380 Urban collector Brick Mill Rd over Dove Nest Branch
New Castle 1929 3,529 Urban local road James St. over Christina River
New Castle 1973 834 Rural major collector SR 9 over Appoquinimink River
New Castle 1918 308 Rural local road Guyencourt Rd. over Reading RR
Sussex 1973 302 Rural local road Craigs Mill Rd over Craigs Pond Spillway
Sussex 1931 157 Rural local road Cods Road over Slaughter Creek
Kent 1977 99 Urban local road Maple Ave over Mispillion River
New Castle 1915 99 Rural local road Private/Park Road over Red Clay Creek
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 2 714 5,884 0 0 0
Rural arterial 101 245,429 1,923,062 1 21,040 10,208
Rural minor arterial 20 11,688 205,586 1 159 7,525
Rural major collector 89 45,902 349,275 2 2,288 8,603
Rural minor collector 30 8,145 65,778 0 0 0
Rural local road 165 24,686 162,706 4 305 866
Urban Interstate 90 335,507 3,983,704 0 0 0
Urban freeway/expressway 30 36,209 585,048 0 0 0
Urban other principal arterial 123 178,193 2,974,223 0 0 0
Urban minor arterial 76 78,598 897,872 2 2,232 27,935
Urban collector 81 37,441 527,452 2 1,068 12,065
Urban local road 65 23,663 115,207 2 1,053 3,628
Total 872 1,026,174 11,795,797 14 28,145 70,830
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 129 $533 2,706,506 119,219
Widening & rehabilitation 20 $59 299,559 19,557
Rehabilitation 137 $1,012 1,821,581 329,493
Deck rehabilitation/replacement 0 $0 0 0
Other structural work 31 $235 648,864 77,187
Total 317 $1,839 5,476,510 545,456

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 49 in 2021

in the nation in % of structurally deficient bridges

1. West Virginia 20.0%
48. District of Columbia 2.0%
49. Delaware 2.0%
50. Nevada 1.0%

Compared to 51 in 2021

in the nation in # of structurally deficient bridges

1. Iowa 4,604
50. Nevada 29
51. Delaware 14

Compared to 43 in 2021

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 17.0%
43. Oregon 3.0%
44. Delaware 3.0%
45. Hawaii 3.0%
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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