The average fuel economy (window-sticker value) of new vehicles sold in the US in November was 24.9 mpg (9.44 l/100 km)—unchanged from the revised value for October, according to the monthly report from Dr. Michael Sivak and Brandon Schoettle at University of Michigan Transportation Research Institute (UMTRI). The value for November 2016 is up by 4.8 mpg since October 2007 (the first month of their monitoring), but down 0.6 mpg from the revised peak of 25.5 mpg reached in August of 2014.
For model year 2017, the EPA revised its methodology for calculating the window-sticker fuel-economy value for new vehicles. In order to make the data for previous model years comparable with model year 2017 (and future model years), the EPA also retroactively revised the corresponding data for some vehicles in model years 2011-2016.
The monthly update for November 2016 includes these retroactive changes to model years 2011-2016. The gray portions of the graph below show the previous values; the red portions of the graph show the updated values.
The University of Michigan Eco-Driving Index (EDI)—an index that estimates the average monthly emissions of greenhouse gases generated by an individual US driver—was 0.83 in September 2016, up 0.01 from the revised value for August 2016 (the lower the value the better). This value indicates that the average new-vehicle driver produced 17% lower emissions in September 2016 than in October 2007, but 4% higher emissions than the record low reached last time in November 2015.
The EDI takes into account both vehicle fuel economy and distance driven (the latter relying on data that are published with a two-month lag).