National Bridge Inventory: Delaware

  • Of the 875 bridges in the state, 17, or 1.9 percent, are classified as structurally deficient. This means one of the key elements is in poor or worse condition.
  • This is down from 39 bridges classified as structurally deficient in 2017.
  • The deck area of structurally deficient bridges accounts for 3.1 percent of total deck area on all structures.
  • 0 of the structurally deficient bridges are on the Interstate Highway System. A total of 82.4 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.
  • 23 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 360 bridges that needed work in 2017.

County Year Built Daily Crossings Type of Bridge Location
New Castle 1971 22,887 Urban minor arterial Red Mill Rd over stream Mill Pond
Kent 1965 13,178 Urban collector Lebanon Rd/SR10 WB over St. Jones River
New Castle 1963 12,252 Urban minor arterial Chapman Rd over I 95, Delaware Turnpike
New Castle 1980 11,050 Urban minor arterial Fourth Street over Christina River
Kent 1941 10,208 Rural arterial US Route 13 over C & D Canal
New Castle 1920 9,465 Rural minor arterial Dupont Pkw/US13 SB over Blackbird Creek
Sussex 1957 7,769 Rural major collector SR 54 over Assawoman Bay
New Castle 1981 5,509 Urban collector Brick Mill Rd over Dove Nest Branch
New Castle 1929 4,439 Urban local road James St. over Christina River
Sussex 1966 1,268 Urban local road Delaware Ave over Broad Creek
Sussex 1964 1,237 Urban other principal arterial US 9 over Delaware Bay
Sussex 1964 1,237 Urban other principal arterial US 9 over Delaware Bay
New Castle 1973 806 Rural major collector SR 9 over Appoquinimink River
Sussex 1973 380 Rural local road Craigs Mill Rd over Craigs Pond Spillway
New Castle 1918 374 Rural local road Guyencourt Rd. over Reading RR
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 101 245,427 2,483,075 1 21,040 10,208
Rural minor arterial 20 11,688 227,417 1 159 9,465
Rural major collector 89 45,902 392,646 2 2,288 8,575
Rural minor collector 30 8,145 79,998 0 0 0
Rural local road 167 24,756 178,105 3 229 853
Urban Interstate 90 335,507 4,217,164 0 0 0
Urban freeway/expressway 30 36,209 705,962 0 0 0
Urban other principal arterial 123 178,234 3,035,778 2 141 2,474
Urban minor arterial 76 78,598 976,628 3 5,524 46,189
Urban collector 82 37,491 579,386 2 1,068 18,687
Urban local road 65 23,663 136,551 3 1,393 5,806
Total 875 1,026,333 13,018,594 17 31,842 102,257
Type of Work Number of Bridges Cost to Repair
(in millions)
Daily Crossings Area of Bridges
(sq. meters)
Bridge replacement 129 $533 2,727,301 119,211
Widening & rehabilitation 20 $59 270,692 19,557
Rehabilitation 137 $1,013 2,001,359 329,754
Deck rehabilitation/replacement 0 $0 0 0
Other structural work 31 $235 706,137 77,187
Total 317 $1,841 5,705,489 545,710

About the data:

Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on January 3, 2022. 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 January 3, 2022.

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 2020 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 44 in 2020

in the nation in % of structurally deficient bridges

1. West Virginia 20.4%
48. Utah 2.1%
49. Delaware 1.9%
50. Texas 1.4%

Compared to 50 in 2020

in the nation in # of structurally deficient bridges

1. Iowa 4,504
50. Nevada 29
51. Delaware 17

Compared to 27 in 2020

in the nation in % of structurally deficient bridge deck area

1. Rhode Island 19.5%
42. Kansas 3.1%
43. Delaware 3.1%
44. Maryland 3.1%
Full State Ranking


  • Source: Data is from the Federal Highway Administration (FHWA) National Bridge Inventory (NBI), downloaded on January 3, 2022. Note that specific conditions on bridges may have changed as a result of recent work or updated inspections.

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