- 1 According to the Federal Highway Administration (FHWA), a bridge is classified as structurally deficient if the condition rating for the deck, superstructure, substructure or culvert and retaining walls is rated 4 or below or if the bridge receives an appraisal rating of 2 or less for structural condition or waterway adequacy. During inspections, the condition 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 and the individual element displays signs of advanced section loss, deterioration, spalling or scour. ARTBA follows the methodology of the FHWA and evaluates bridge status without applying the 10-year rule.
- 2 ARTBA analysis of FHWA data, includes all bridge construction-related spending on projects approved by FHWA between 2005 and 2014.
- 3States report the cost of proposed bridge work for each bridge to the Federal Highway Administration as part of the bridge inventory data each year. Each highway agency is encouraged to use its best available information and established procedures to determine bridge improvement costs.
- 4 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, and the Dwight D. Eisenhower National System of Interstate and Defense Highways. Other principal arterials serve major centers of urban areas or provide mobility through rural areas. Freeways and expressways are similar to interstates, with directional lanes generally separated by a physical barrier, and access/egress points generally limited to on- and off-ramps. Minor arterials are used for trips of moderate length, serve smaller geographic areas and connect to the higher arterial system. 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.
- Source: Bridge data is from the = $year; ?> National Bridge Inventory ASCII files, released by the Federal Highway Administration in January = $year + 1; ?>. Note that specific conditions on bridges may have changed as a result of recent work.