The average fuel economy of new cars has increased 5 mpg in the last 10 years, a 26 percent improvement, according to the EPA.
Just over 56 percent of U.S. vehicle sales so far this year -- 8.9 million vehicles -- have been of SUVs, crossovers, pickups and other larger vehicles, up from 53 percent during the same 11 months of last year.
Despite the market shift towards crossovers and SUVs, the fact that individual vehicles continue to get more efficient means the regulations still have an impact, says Dave Cooke, vehicles analyst in the Clean Vehicles Program at the Union of Concerned Scientists.
“Without regulations in place, fuel economy would be moving backwards, just like it did in the 1990s and early 2000s,” Cooke said in a blog post. “The regulations are actually preventing even more emissions than originally projected. Additionally, any slowdown in fleet fuel economy improvement related to a shift in the sales mix will be temporary, since all vehicles will continue to improve.”
Mazda tops list
Mazda was the most fuel-efficient brand in the 2014 model year, posting a 29.4 mpg average. Subaru came in second at 27.6 mpg, Hyundai was third at 27.5 mpg, while Honda and Nissan rounded out the top five at 27.3 mpg and 27 mpg, respectively.
Domestic auto makers, which sell considerably more pickups than their foreign competitors, were ranked as the three least-efficient manufacturers.
Continuing the industry's pace of fuel economy improvements will be a challenge as the fuel economy and emissions rules toughen in the years ahead, according to Auto Alliance, a Washington, D.C., trade group representing the Detroit 3 and nine other auto makers.
“Our compliance is based on sales, not what we put on showroom floors,” Auto Alliance said. “Consumer purchases of fuel-efficient vehicles still go up and down with the price of gasoline, and sales of our most energy-efficient vehicles will need to rise to meet future standards.”
Mr. Grundler says auto makers are already selling vehicles that can comply with future regulatory standards. He said one model of the Ford F-150 pickup with two-wheel drive and a 2.7-liter engine complies with the EPA's 2024 requirements already, for example.
“The technology is being adopted at a pace faster than the agencies anticipated,” Mr. Grundler said, noting that the industry is just three years into the EPA's 14-year greenhouse gas program.
“We're taking the long view here,” he said. “This is a marathon, not a sprint, and that's what addressing climate change will require.”