Washington, D.C. – Average carbon dioxide (CO2) emissions have decreased in the U.S. for the sixth consecutive year, while fuel efficiency has improved slightly for new cars and light-duty trucks, according to a new report by the Environmental Protection Agency (EPA).

The EPA projects a small improvement in 2010, based on pre-model year sales estimates provided by the automakers, to 395 grams of CO2 per mile and 22.5 miles per gallon. The EPA warned that there may be uncertainty in the numbers as they were made during the atypical automotive market in 2009, but the 2010 final data will be available in next year’s report.

For 2009, the last year the EPA has final data from automakers, the average CO2 emissions from new vehicles were 397 grams per mile, with average fuel economy of 22.4 mpg.

The report confirms that average CO2 emissions have decreased and fuel economy has increased each year beginning in 2005. The positive trend beginning in 2005 reverses a long period of increasing CO2 emissions and decreasing fuel economy from 1987 through 2004.

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