American Council for an Energy-Efficient Economy (ACEEE), June 2014, by Siddiq Khan.
http://www.aceee.org/blog/2014/06/how-save-2-million-barrels-oil-day

Provides a summary of efforts to increase fuel savings in trucks through continued promotion of fuel efficiency and greenhouse gas emissions standards for medium- and heavy-duty vehicles and engines built for the 2014 to 2018 model years and to extend the EPA and NHTSA program beyond 2018.