New cars and trucks sold in the United States during the 2012 model year returned an average of 23.6 mpg in combined city and highway driving, a record figure for fuel economy, the Associated Press reported.
The gains, measured across all automakers that sell vehicles in the America, came primarily through improvements made to engines and transmissions, AP said, citing data from a report released by the U.S. Environmental Protection Agency.
The overall mileage figure for 2012 — the latest year for which full data are available — was 1.2 mpg above 2011's number, marking the second-largest annual mpg increase in 30 years, EPA said.
The agency is estimating that the average mpg for 2013 model year vehicles will rise 0.4 mpg to 24 mpg. Final figures for 2013 won't be available until 2014, AP said.
Between the 2012 and 2025 model years, the federal government will require automakers to gradually improve the average fuel economy of their vehicle lineups. By 2025, automakers must achieve a corporate average fuel economy figure of 54.5 mpg.
Among manufacturers, those that produce smaller vehicles are faring better than those that make larger vehicles and trucks. Chrysler Group, which makes Ram pickups, finished last in the EPA report, with corporatewide fuel economy of at 20.1 mpg. General Motors Co., which makes Chevrolet and GMC trucks, was third from the bottom at 21.7 mpg, according to the report.
Mazda led all automakers with an average of 27.1 mpg, followed by Honda ( 26.6) and Volkswagen (25.8).
The EPA cited multiple-speed transmissions and turbocharging among the technologies that are helping to improve fuel economy. Automakers also have cut vehicles' weight through increased use of lighter materials.
"Manufacturers and suppliers continue to develop great new technology," said Christopher Grundler, director of the EPA's office of Transportation and Air Quality. "More consumers value fuel economy than in the past. So, there was very strong demand."
He added that many automakers already are meeting fuel economy standards for the 2016 model year thanks to these innovations.
