New Ways Carmakers Are Getting You More MPG

·6 min read

CR highlights the fuel-saving tech that might be in your next car—and the potential trade-offs in your driving experience

By Benjamin Preston

Although most automakers say all-electric vehicles are the future, their engineers also have been busy making fuel-efficiency improvements to the gasoline-powered cars, SUVs, and trucks that most U.S. drivers still rely on. For a variety of reasons, including consumer demand and government fuel and emissions standards, automakers have been forced to invent gas-saving innovations as they try to squeeze out incremental improvements to fuel economy.

Consumers shopping for new cars now face a plethora of these innovations, such as gasoline direct fuel injection, automatic transmissions with more gear ratios, turbocharged engines, and stop/start systems that shut off the engine instead of allowing it to idle. Few of these technologies significantly increase fuel efficiency or reduce tailpipe emissions on their own, but working together they can have a cumulative effect.

To help car shoppers navigate these fuel-saving features, CR talked with manufacturers, experts, and consumers to find out exactly how each technology works. We combined those insights with observations from our own testers, who have evaluated these features in real-world driving conditions. We’ve found that some of these technologies, such as turbocharged engines, can end up compromising drivability and sometimes cause reliability problems.

“There are no free rides in this business,” says Gabe Shenhar, associate director of CR’s auto test program. “Drivers might find the stop/start annoying, or turbo lag could make a car hesitant to accelerate. Aerodynamic styling might result in a lower, curvier car that compromises visibility and ease of access.”

Through our dynamic ratings chart, you can discover which vehicles deliver the most miles per gallon. Below, you can learn the benefits of each gas-saving technology as well as any potential drawbacks. You can arm yourself with this information as you shop for a new or used vehicle.

Most of the highest-mpg vehicles we highlight are hybrids, meaning they combine internal combustion engines and electric motors to save fuel. Most also have electronic continuously variable transmissions (eCVTs), which can save energy by regulating engine speed. A few of the models on our list have traditional gas-powered engines and achieve strong fuel economy without using hybrid technology.

We don’t highlight battery-only electric vehicles, called EVs, because they don’t use any gasoline and currently represent only a sliver of the U.S. new-car market. Diesel-powered cars also get good fuel economy, but they’re not on our list because they’re not necessarily cleaner burning, and the selection among U.S. passenger vehicles has dwindled.

The newest gas-saving innovations, taken together, have made it possible for a pickup truck to achieve highway fuel economy in the mid-20s, to say nothing of the many SUVs and cars that now push into the 30-plus mpg range. The gains have shown up across the board. According to the Environmental Protection Agency, the average fuel efficiency for new cars in the U.S. improved to a record 25.4 mpg in 2020 and was projected to stay about the same for 2021. In the process, automakers also decreased harmful tailpipe emissions by about 24 percent since 2004, a new low that has environmental and public health benefits.

“When car manufacturers report an increase in mpg, it’s due to the collective use of multiple technologies,” says Bassem Ramadan, PhD, head of the mechanical engineering department at Kettering University in Flint, Mich. “There is no single technology that is or will be the silver bullet that will dramatically improve fuel efficiency and reduce emissions at the same time.”

What About EVs?

So why all this innovation with gas-powered engines even though electric vehicles clearly outperform all gas-powered cars when it comes to energy efficiency? The case for them is strong: EVs use no gasoline and emit zero tailpipe emissions. They can be quick and very satisfying to drive. And an exclusive CR analysis shows big savings on maintenance and operating costs over time when compared with traditional gasoline-powered vehicles.

The answer is that EVs are not yet a solution for many drivers and are up against several obstacles that so far have held back wider adoption: long charging times, limited (but ever-increasing) battery range, and higher prices. Market demand for EVs and plug-in hybrids has been growing quickly over the past few years—and pure EVs account for the lion’s share of plug-in sales—but together they still account for only 4 percent of the U.S. market.

“Automakers have been slow to build EVs in part because until recently, battery costs have been quite high,” says Chris Harto, senior transportation policy analyst at CR. “That is rapidly changing. Expect to see a lot more compelling EVs over the next few years.”

Based on a flurry of automaker announcements, it’s clear that the industry has plans to move toward more electric models. For example, BMW and Mercedes-Benz—leaders in automotive research and development—say they plan to reach 50 percent electrification across their lineups by 2030. And certain other brands, such as Volvo, have pledged to eventually have an EV option for every model they offer. Some newer automakers—notably Tesla—offer only EVs.

At the same time, Tesla and other companies have been building out national public charging networks, with a growing number of DC fast-charging stations that can make on-the-road charging more palatable for drivers.

According to the federal Alternative Fuels Data Center, there are currently more than 50,000 EV charging stations in the U.S., almost double the number there were in 2019. Depending on the battery and charging equipment, DC fast-chargers can add 60 to 80 miles to EV range in 20 minutes, about the time it takes to eat a quick meal on the road.

“The reality is that most of the effort on internal combustion engines is starting to wind down in favor of electric development,” says Sam Abuelsamid, principal research analyst at Guidehouse Insights, a market research firm. “Much of the restructuring we’ve seen at automakers and suppliers in the last few years has involved getting rid of engineers with engine expertise in favor of more software and electrical engineers. That’s where all the major action is today.”

Editor’s Note: This article has been updated since it originally appeared in the November 2020 issue of Consumer Reports magazine.

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