Reuss also sees the surge in sales of trucks and other, less fuel-efficient vehicles as more an aberration than trend, insisting there has been "a permanent change" in the public mindset against "wasteful" vehicles.
UMTRI researcher Sivak noted that the decline in average fuel economy would have been much worse if not for the better mileage of even the biggest new trucks coming to market today. A diesel version of the Colorado pickup that Chevrolet is planning is expected to get more than 30 miles per gallon.
Not everyone is so upbeat. Some observers worry the industry will fall far short of tough new mileage mandates, such as the 54.5 miles per gallon corporate average fuel economy target for 2025.
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"If consumers decide they don't want to pay the extra cost of a more fuel-efficient vehicle because it doesn't pencil in, it could make it difficult...to improve fuel economy and reduce emissions," said IHS Automotive senior analyst Stephanie Brinley.
Manufacturers are finding themselves diverting some of the profits from the sale of those big trucks to prop up demand for more efficient vehicles—especially hybrid and plug-based models such as the Ford Focus Electric. The maker trimmed $6,000 off the manufacturer's suggested retail price of its compact battery-electric vehicle last month, on top of an earlier $4,000 cut.
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Compounding the industry's challenge, manufacturers must also meet strict mandates set out by California regulators, including minimum sales targets for so-called zero-emissions vehicles, such as the Focus Electric, the Tesla Model S and the upcoming hydrogen fuel cell vehicles Honda and Toyota plan to launch next year. Recent sales trends suggest that complying with the rules will be costly and difficult.
So, while lower fuel prices may be great for the American consumer, they definitely have their downside.