Definitions and Methodology
The BridgeTech NBI Database tool only returns Bridges. All culverts have been filtered.
- Deficiency (Structurally Deficient, SD, and Functionally Obsolete, FO) are defined in http://www.fhwa.dot.gov/bridge/0650dsup.cfm (Note: Bridges with a Year Built or Year Reconstructed within the past 10 years will not be assigned a deficient status.) Therefore, when we refer to the deficiency being calculated not using the 10-yr rule, the status will be calculated without taking into consideration the year built or the year reconstructed.
- A text definition of SD and FO can be found in the Bridge Conditions section of Chapter 3 of the latest "Status of the Nation's Highways, Bridges, and Transit: Conditions & Performance, Report to Congress" http://www.fhwa.dot.gov/policy/2010cpr/
- All codes for all items in the National Bridge Inventory can be found in the Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation's Bridges located at : http://www.fhwa.dot.gov/bridge/bripub.htm
- Definition of the National Highway System (NHS) can be found at: http://www.fhwa.dot.gov/planning/national_highway_system/