Like the rest of us, the Environmental Protection Agency seems to have noticed that cars are an increasingly rare sight on American roads, having been rapidly displaced by seemingly ever-larger trucks and SUVs. In its impact analysis of the agency’s new tailpipe emissions standards, a final version of which was unveiled this week, the EPA considers its own role in killing the sedan.
The issue, the EPA analysis says, may have been the “attribute-based GHG standards for light-duty vehicles,” which first applied to new cars released in 2012. While federal regulators had distinguished between passenger and “non-passenger” vehicles since the 1970s, this Obama-era change amended U.S. corporate average fuel economy (CAFE) standards such that vehicles would be held to different emissions standards based on their size—specifically, the vehicle’s wheelbase multiplied by its track length (width). This meant that larger cars—those classified as light trucks—would be held to less stringent standards than passenger vehicles. What might sound like a wonky bureaucratic tweak has dramatically changed how Americans drive.
In less than a decade after that change took effect—between 2012 and 2021—the EPA found that the percentage of new vehicle sales classified as passenger cars and those classified as light trucks has essentially flipped. In 2012, 64 percent of new vehicle sales were classified as passenger vehicles, while 34 percent were classified as light trucks. By 2021, light trucks accounted for 63 percent of sales while passenger vehicles accounted for 37 percent of sales. “Sedans have largely been replaced with taller vehicles such as truck-like sport utility vehicles (SUVs) and crossover utility vehicles (CUVs),” the agency writes. Pickup trucks’ share of new cars sales jumped from 10 to 16 percent over the same period. During that time, the overall average footprint of new cars grew by more than 5 percent.
American autos aren’t bigger because consumers have suddenly embraced off-roading, the construction trades, or home improvement projects. They’re bigger because automakers want to escape regulations. Each manufacturer is required to comply with boutique greenhouse gas emissions standards, which are calculated based on the size and capabilities of the cars in their fleets. Smaller cars are held to different standards than larger cars. So are those with specialty features like all-wheel drive or large towing capacities. By changing the makeup of their fleets, in other words, car companies can change the standards to which they’re held. Those greenhouse gas emissions targets are measured in grams of carbon dioxide or its greenhouse gas equivalent per mile.
As the EPA points out in its impact analysis, carmakers’ shift to larger vehicles has undermined the effectiveness of EPA regulations. The recent, rapid growth in car size, the agency writes, “has permitted compliance under higher numerical standards.” As a result of the increased average footprint of cars, automakers in 2021 could emit eight more grams per mile than in 2012. The EPA had projected the rules it implemented that year would result in average targets that were 22 grams per mile lower than those that were actually in place in 2021. And it therefore projected its 2012 rules would reduce carbon dioxide emissions by 3.5 percent per year from 2012 through 2021. Instead, the agency found it reduced emissions by about 2 percent per year.
The EPA—which did not respond to a request for comment in time for publication—seems aware of the sweeping, unintended consequence of changing the way that cars are classified. I’ll be writing soon about the ways its new tailpipe emissions rules do and do not address that challenge. On its own, though, the agency’s analysis of how dramatically its policies have shaped the way Americans drive should serve as a cautionary tale for just how influential even the most boring regulatory shifts can be when it comes to long-term emissions.
