1. FHWA. 2013 Status of the nation’s highways, bridges, and transit: conditions & performance. Washington, DC: United States Department of Transportation; 2013.
2. FHWA. Count, Area, Length, and ADT of Bridges by Functional Classification. FHWA Bridges and Structures [Online], Available from: https://www.fhwa.dot.gov/bridge/fc.cfm; 2014
3. Analysis of Recent Bridge Failures in the United States;Wardhana;J Perform Constr Fac,2003
4. FHWA. Bridge preservation guide. Washington, DC: Federal Highway Administration; 2011. FHWA-HIF-11042.
5. FHWA. Structure Type by Year Built Count of Bridges 2011. FHWA Bridges and Structures. [Online] June 28, 2014. Available from: https://www.fhwa.dot.gov/bridge/nbi/yrblt11.cfm