University of Michigan
According to a monthly report by the University of Michigan, the average fuel economy of newly purchased vehicles during the month of February 2013 has hit an all time high.

The average fuel-economy (window-sticker) value of new vehicles sold in the U.S. in February was 24.5 mpg. This ties the record high reached in January and is up 4.4 mpg from the value in October 2007 (the first month of our monitoring). For a description of the calculations and the recent mpg values, click here.

The University of Michigan Eco-Driving Index (EDI)--an index that estimates the average monthly emissions of greenhouse gases generated by an individual U.S. driver--stood at 0.80 in December. This value indicates an improvement of 20% since October 2007. The EDI takes into account both the fuel used per distance driven and the amount of driving (the latter relying on data that are published with a two-month lag). Please visit this page for a brief description of what the EDI is, how it is calculated, and the current and recent values of the EDI.