In 2017, Mazda announced its “Sustainable Zoom Zoom 2030 Vision,” which promised to “perfect an internal combustion engine that produces fewer carbon dioxide emissions.”
And Mazda is not alone. Five other automakers — Honda, Subaru, Volkswagen, BMW and GM — sold cars that were less efficient, on average, in 2022 than in 2017.
This drop in efficiency might seem puzzling at a time when the planet keeps shattering temperature records and the Biden administration is raising fuel efficiency standards.
Transportation emissions rank as the biggest contributor to climate change in the United States. Over the years, carmakers have made big strides in reducing them, by making more fuel efficient gas-powered cars and trucks. They’ve also been introducing an increasingly robust lineup of hybrids and EVs.
So why are some major carmakers becoming less, not more, efficient? A big part of the reason: Neither carmakers nor Americans seem to be able to resist the allure — and profits — of SUVs and pickup trucks.
SUVs and trucks are replacing sedans
Americans have an enduring love of big cars. That relationship got rocky when gas prices started to soar in the mid-2000s, leading to the introduction of smaller, fuel efficient cars to the U.S. market such as the Ford Fusion, Chevy Cruze and Honda Fit. But the American passion for gas guzzlers was rekindled by a long stretch of low gasoline prices between 2015 and 2022.
In response, automakers shifted production from sedans to SUVs, which tend to be more profitable and less fuel efficient, according to Mark Schirmer, a spokesperson for Cox Automotive, an auto industry research firm.
“The drop in [small] cars and increase in SUVs is definitely detrimental to overall industry fuel economy,” he said.
Americans are buying fewer smaller cars, and carmakers have stopped selling some models, including Ford’s Fiesta, Focus, Fusion and Taurus, Chevy’s Impala and Cruze, the Honda Fit, the Toyota Yaris and the Volkswagen Beetle. Last year, most vehicles sold in the United States were SUVs, according to a Kelley Blue Book estimate — up from just below half in 2018.
“In recent years, Mazda has changed its product lineup to offer more crossover SUVs, to align with customer demand in the U.S.,” Mazda spokesperson Tamara Mlynarczyk wrote in an email.
Mazda’s best seller, the CX-5 SUV, for example, gets up to 26 miles per gallon compared with 31 miles per gallon for its Mazda 3 sedan, which sold a fifth as many units last year. GM, which saw the fuel efficiency of its new cars dip by 3.5 percent over the past five years, sells four times as many Silverado pickup trucks — which get between 15 and 26 miles per gallon — as Malibu sedans, which get 30 miles per gallon.
These bigger cars burn more gas and cost more to fill up.
Don’t expect gas and diesel cars to get more efficient
Although SUVs have gotten somewhat more efficient in recent years, the days of steady improvement in the efficiency of gas-powered engines are probably over, according to Schirmer.
The last big jump in combustion engine efficiency came a decade ago, he said, when automakers switched from V-8 engines to turbocharged four- or six-cylinder engines, which deliver a similar amount of power while burning less fuel. But after a century of improving car engines, it’s getting tougher for automakers to find new efficiencies.
“The gains that are made on pure gasoline engines are getting more difficult and more expensive to make,” Schirmer said.
The next big jump, he said, is likely to come only when automakers electrify those cars and trucks.
EVs and hybrids keep U.S. fuel efficiency rising
That day is getting closer. Electric vehicle sales are rising in the United States. Last year, nearly 10 percent of cars and trucks sold here were electric, according to EPA data. Hybrids made up a similar share of sales.
The growing sales of electric and hybrid vehicles are pretty much the only thing keeping the average fuel efficiency of U.S. cars and trucks rising.
The EPA estimates the fuel economy of EVs and hybrids in “miles per gallon equivalent” units, which measure how far they can drive using an amount of electricity that has roughly the same amount of energy as a gallon of gasoline. EVs and hybrids generally have much higher efficiency ratings than gas-powered cars (with a few exceptions, including the hulking, inefficient Hummer EV).
The efficiency of gas- and diesel-powered cars and trucks started to stagnate in 2016, around the time that gasoline prices fell. Since then, roughly 90 percent of the improvement in the fuel efficiency of new U.S. vehicles has come from EVs and hybrids being sold in greater numbers.
A tale of two auto markets
From now on, the story of fuel efficiency in the United States is likely to be a tale of two types of car buyers. A growing share of Americans will buy more efficient electric vehicles and hybrids. But another large group will continue to buy gas guzzlers.