Average fuel economy for new 2013 model vehicles sold in the US is 24.6 mpg, up 1.1 mpg from 2012 models, according to researchers at University of Michigan. Fuel economy is up 4.6 mpg since October 2007, when U-M researchers began collecting data. The researchers expect 2013 model year vehicles to improve 1% to 1.2% over 2012 vehicles.