This week, the US EPA noted in a report that 2012 vehicles in aggregate now have the highest fuel economy ever – at an average of 23.6 miles / gallon – resulting in the lowest carbon emissions per mile on average of 376 grams / mile. Technology for fuel economy continues to drive this trend further. Significant increases in emission reductions are also targetd for 2016 as part of the American climate plan.
http://ens-newswire.com/2013/12/12/u-s-epa-fuel-economy-of-new-vehicles-sets-record-high/