We could have done much better, with efficiency rising perhaps as much as 4 percent or 5 percent a year, John DeCicco, a research professor emeritus at the University of Michigan Energy Institute, told me. After fuel economy standards were raised under George W. Bush and then even more under Barack Obama, manufacturers began installing a host of new technologies to make cars more efficient. Most vehicle types became significantly cleaner — average fuel economy for sedans, for instance, grew to 30.9 m.p.g. in 2019 from 25.3 m.p.g. in 2009, a gain of about 22 percent.
So how did most cars get so much better without changing the bigger picture very much at all? It’s simple, DeCicco says: We ate our gains.
As cars became more efficient, people began buying larger, heavier and more powerful cars. In particular, we got hooked on sport utility vehicles and those formless blobs on wheels known as crossovers, which became one of the hottest segments of the car business. A decade ago, about half of all cars sold were sedans, which are some of the most efficient vehicles on the road, and about a quarter were S.U.V.s, which are some of the least efficient. By 2019 only a third of cars sold were sedans, and about half were small or large S.U.V.s. Given more efficient cars, we bought more car.
Federal policy hasn’t helped. In 2017 the Trump administration began to undo Obama’s fuel rules, a reversal that fostered uncertainty and division in the car industry and perhaps pushed carmakers to lay off new fuel-saving technologies.
The growing adoption of electric vehicles over the last decade did little to counteract these larger forces; any environmental benefits we got from zero-emission E.V.s were swamped by the much larger market shift toward bigger cars. While electric cars are important, DeCicco wrote recently on his blog, “much more stringent clean car standards are the real priority for putting the U.S. automobile fleet on track for climate protection.”
Naturally, the car industry is not in favor of significantly stricter fuel standards. Carmakers expect Biden to raise fuel standards, but they are pushing for something less than the Obama rules, which would have required passenger vehicles to achieve an average of 54.5 m.p.g. by 2025.
Among environmentalists, there is more than a little suspicion that the flurry of new electric vehicle announcements — including G.M.’s pledge to sell only zero-emission passenger cars by 2035 — is a negotiating tactic to forestall very tough fuel standards. Carmakers will gladly give us some awesome E.V.s tomorrow for lenient rules today.