The average fuel economy for all new cars sold in the U.S. in October held fast at 25.3 mpg following a 0.5 mpg dip the previous month, the biggest for that period in nearly three years. The study, conducted by Michael Sivak and Brandon Schoettle of the University of Michigan's Transportation Research Institute, calculates the sales-weighted fuel economy through monthly sales of individual new models of light-duty vehicles, including cars, SUVs, vans and pickup trucks, and is based on "window-sticker value" as opposed to real-world mileage.
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While the nation's fuel economy did stabilize last month, it's also the first time mileage failed to make a month-to-month improvement between September and October in at least seven years. The October trend from 2008 to 2013 was for fuel economy to go up by an average of 0.63 mpg, with the greatest improvement by a full 1 mpg coming in 2009, and the smallest upward increment of 0.4 in 2008 and 2010; those rebounds followed an average August-to-September decline of 0.33 mpg during the six-year period.