Is CAFE making cars bigger?

WASHINGTON -- The tough fuel-economy standards that took effect in 2012 are getting tougher every year. So why are cars getting bigger?

The average new vehicle's "footprint" -- the rectangle formed by its wheelbase and track width -- hit a record 49.9 square feet in the 2015 model year, according to the EPA, up by about 1 square foot, or 2 percent, since the agency been tracking the measure in 2008.

The EPA says that growth mostly reflects shifting sales toward trucks and SUVs. And to be sure, cars and trucks have been growing for decades to reflect the visual tastes of designers, the safety concerns of engineers and consumer desire for more interior space.

But these days, analysts say, automakers have an added incentive to make their cars a little bit larger: more forgiving fuel economy targets.

The Obama administration's so-called National Program assigns mpg and CO2 emission targets to vehicles based on their footprint, and requires annual improvements for every footprint size. They're also set on curves, one for cars and another for light trucks, in which smaller vehicles face more stringent targets than larger ones.

For manufacturers, that means adding just a few inches to a vehicle's wheelbase during a redesign can result in a lower mpg target -- sometimes 1 to 2 mpg lower -- than if the vehicle had stayed the same size. The redesigned vehicles must still get better fuel economy than their predecessors, but don't need to stretch as far to meet their targets.

"Cars are changing their dimensions in order to take advantage of this, but I don't think it's anything new," said Dave Sullivan, an analyst at AutoPacific Inc. "We've been using every available credit or loophole that the system allows for years now."

To see how the targets work, take the Buick LaCrosse. The new model is 2.7 inches longer between the wheels, and about 1.2 inches wider. That roughly 2.1-square-foot size difference, says GM spokesman Nick Richards, helps the full-size sedan meet the tastes of U.S. and Chinese customers.

It also boosts the footprint to 50.1 square feet, yielding a 2017 model-year target of 36.3 mpg under the government's corporate average fuel economy rules. That's up from the previous model's 35.7 mpg CAFE target, but 1.4 mpg less than the 37.7 mpg it would have faced had GM carried the smaller 2016 LaCrosse into the 2017 model year, according to calculations provided by the Union of Concerned Scientists.

There are many more like the LaCrosse. An Automotive News review of 25 vehicles redesigned since the footprint-based standards took effect in 2012 found that 21 models got bigger -- from cars to pickups, large and small, from luxury and mainstream brands alike.

Analysts broadly agree that compliance is just one of many incentives automakers have to make vehicles larger. But some of them are concerned that the trend could undermine the environmental goals of the government's mpg and CO2 standards if left unchecked. And that concern could have big implications as the industry, government and other stakeholders embark on a long and intensive review to determine whether the standards need to be strengthened or loosened.

"We know it's having a negative impact on the benefits of the program -- bigger footprint means less-stringent standards, and it's a bigger footprint at the redesign process essentially at no cost, meaning you get a less stringent standard for free," says Roland Hwang, transportation director at the Natural Resources Defense Council. "Based on the evidence you have, it requires the regulators to look at this issue more closely." 

EPA officials say they are watching the issue closely, but for now, they doubt that manufacturers are seeking to exploit the footprint-based standards, which they say were designed to apply the same degree of difficulty to different vehicle sizes. In fact, the agency argues, making vehicles larger makes it more difficult, not less, to realize fuel-economy improvements because of the weight of the added sheet metal. 

"Other things being equal, larger vehicles will emit more [greenhouse gas] emissions and achieve lower fuel economy than smaller vehicles," Christopher Grundler, director of the EPA's Office of Transportation and Air Quality, said in a statement to Automotive News. "One should not assume that it is easier for a larger vehicle to meet a less stringent numerical standard."

Steve Skerlos, an engineering professor and researcher at the University of Michigan, predicted the move toward larger cars in a 2011 paper modeling the engineering changes automakers would make in response to the CAFE and greenhouse gas regulations.

Increasing a car's footprint, he told Automotive News, is a "straightforward and reasonably inexpensive way" to deal with the annual targets, along with engine technology and weight reduction. (The 2017 LaCrosse, for example, weighs 300 pounds less than its smaller predecessor.)

"Having this option gives consumers what they want while lowering their targets, which means lower expenditures on the other fuel-saving approaches," he said.

Even so, said Dave Cooke, auto analyst with the Union of Concerned Scientists, the bigger footprint has limited impact because such a change can be made only every five to six years in a redesign and only reduces standards by 1 or 2 mpg.

A bigger motivator, he figures, is ever-tougher crash tests -- namely the small-overlap crash from the Insurance Institute for Highway Safety. Among other things, the larger footprint expands the area of protection around the passengers.

"I would say that certainly part of this increase is safety-related," Cooke said. "The real question is: Are we seeing this unfortunately as a compliance strategy?"