U.S. new car fuel economy dips in December

The average fuel economy of a new U.S. vehicle purchased last month fell about two percent from November and was down slightly from a year earlier, reflecting what may be the public's reaction to fuel prices that have steadily fallen since eclipsing the $4 threshold in May.

The average new light-duty vehicle had achieved 22.2 miles per gallon, down from 22.7 mpg in November and from 22.3 mpg in December 2010, the University of Michigan Transportation Research Institute (UMTRI) reported. New-vehicle fuel economy reached a recent high of 23 mpg in March 2011.

Overall, new car fuel economy has steadily risen in recent years as gas prices have gone up, hybrid-electric vehicles have gone more mainstream and automakers have found ways to make gas-powered engines more efficient. Four years ago, UMTRI recorded new-vehicle fuel economy in the 20 to 20.5 mpg range. Meanwhile, U.S. fleetwide fuel economy rose in 2010, the most recent year the U.S. Environmental Protection Agency tracked such figures and the fifth consecutive annual increase. The average 2010 model year car across all makes got 22.5 miles per gallon, up slightly from the 22.4 average for the 2009 model year and about 17 percent higher than the 2004 model year average, the EPA said in November 2010.

Still, the recent decline may reflect how more Americans may be returning to larger-engined vehicles and SUVs amid the steady decline in gas prices. Fuel prices averaged about $3.33 a gallon as of Jannuary 1, down from about $3.60 a gallon in early September and from about $4 a gallon in May, according to AAA.