It's working.

Concerted efforts by automakers to meet new, more stringent fuel-economy requirements are gradually driving up the efficiency of new passenger vehicles sold in the U.S.

A report from the University of Michigan Transportation Research Institute pegged the average gas mileage of new vehicles sold during March at 24.1 miles per gallon. It's the first time the measure has exceeded 24 mpg.

The March figure is 0.2 mpg better than in February, when the average was 23.9 mpg, and 0.5 mpg better than the January figure, at 23.6 mpg.

The institute first began monitoring sales-weighted mileage data in October 2007. At that time, the average was roughly 20 mpg.

The increase can be attributed not only to higher corporate average fuel economy (CAFE) regulations starting for the 2012 model year, but also to some effects of rising gas prices, which are nearing a national average of $4 a gallon.

CAFE standards for the 2017 through 2025 model years are expected to be finalized and signed into law later this year.

The proposed standards for those years will raise CAFE levels to 54.5 mpg, which translates into EPA window-sticker gas mileage numbers in the low to mid 40s.

Meanwhile, as the new-car market overall continued its upward trend, relatively lower sales in 2008 through 2010 mean the U.S. fleet will actually get more efficient slightly faster than it would have if sales in those years had stayed at their 2006 heights.


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