The concept of sustainability in bridge design is becoming a major issue. Architects (and others) have a certification program for “Leadership in Energy and Environmental Design” or Leed for short.
The purpose is to make the best structures, with environmental friendly products, that leave the smallest footprint possible. Bridge design doesn’t have a certification system yet but it will. (Email me and we can start one!)
Here is a short article in Aspire magazine about Green bridges.