The CAFE Numbers Game: Making Sense of the Fresh Fuel-Economy Regulations – Feature – Car and Driver
The CAFE Numbers Game: Making Sense of the Fresh Fuel-Economy Regulations
Update 8/29/12: This week, the EPA and DOT finalized automotive fuel-economy and greenhouse-gas regulations for the two thousand seventeen to two thousand twenty five model years. In the year since the plans were very first proposed, very little has changed—just some minor tweaks to calculations so complicated they crashed the C/D office Apple IIE. What hasn’t switched, however, is just how aggressive the government regulations are in attempting to reduce gasoline consumption. The article below, published very first in the November two thousand eleven issue of Car and Driver magazine, explains the fresh fuel-economy rules, as well as their benefits and drawbacks.
It was less than two years ago that the Obama administration implemented fresh Corporate Average Fuel Economy (CAFE) regulations that boosted the auto industry’s mandatory overall fleet mpg from 25.Three in two thousand ten to 34.1 by 2016. This was, by far, the fattest CAFE increase in decades. But now the administration is pushing the standards even higher.
In July, President Obama announced a proposal to raise the auto industry’s mpg requirement to 54.Five by 2025. That’s a 59-percent increase over the two thousand sixteen bogey and basically double—99 percent higher than—the current two thousand eleven standard of 27.Trio mpg.
As with the 2012–16 rules, this fresh proposal is devilishly complicated and bristling with incentives that favor certain technologies and penalize others. But here are a few key items to keep in mind:
Very first, like the current 2012–16 rules, these fresh standards are size based. That means there’s a formula to calculate the required CAFE—within limits—for each car based on its “footprint,” which is the product of its wheelbase and track dimensions. In 2011, for example, the required CAFE mpg for the smallest car would not exceed 31.Two, while even the largest car was assigned at least twenty four mpg. For 2025, these car boundaries go up to 61.1 and 45.6. Truck mpg is calculated in similar style using a different formula. For 2011, the truck mpg ranged from 21.1 to 27.1. In the two thousand twenty five proposal, it spans 30.Two to 50.Four mpg. Notice that the formula has been adjusted so that the low end of the range rises less than the high end to help accommodate large trucks.
2nd, because these CAFE requirements are based on size, every car company actually finishes up with a different CAFE requirement, depending on the mix and size of cars and trucks that it actually sells. For every model year, each company must calculate the CAFE requirement for all models it markets and then determine the sales-weighted average for its actual mix. Therefore, a company such as General Motors, with its strenuous share of large pickups and SUVs, will have a lower CAFE requirement than Suzuki, which primarily produces smallish cars and SUVs.
Third, CAFE mpg is very different from the fuel-economy-label mpg numbers on every fresh car. That’s because the CAFE figures are based on the original city and highway fuel-economy tests established in the Seventies, while the window-sticker numbers combine those values, along with the results of three other emissions tests, to produce mpg figures that better-match real-world driving. In general, the combined mpg on a vehicle’s label is about twenty percent lower than the CAFE mpg.
Hidden within this web of rules are a number of subtleties. For example, the nominal 54.5-mpg requirement represents a certain reduction in the tailpipe emissions of carbon dioxide. The actual mpg requirement will be more like 49.6, with the rest of the greenhouse-gas reduction coming from a switch to higher-efficiency air-conditioning systems using more environmentally friendly refrigerant.
The manufacturers will also get mpg credits for adopting efficient technologies that often showcase no effect on the official test cycles. These include active grille shutters, electrical fever pumps, stop-start systems, high-efficiency lights, and solar roof panels. The credit for such items could amount to about three mpg if several are used or even more if a manufacturer provides data to justify it.
Then there’s extra credit for electrical, plug-in hybrid, and fuel-cell vehicles. These machines already garner very high CAFE ratings, as they use little or no gasoline, but to encourage their sales, the government will factor each sale of an electrical vehicle by Two.0 in model year 2017. In other words, if you sell Ten,000 electrified vehicles—either battery powered or fuel cell—they will be counted as 20,000 when calculating that company’s fleet fuel economy. This factor will phase down to a multiplier of 1.Five by 2021. For plug-in hybrids, the factor will embark at 1.6 in two thousand seventeen and phase down to 1.Trio in 2021.
Recognizing that full-size pickups have been slow to adopt hybrid technology, there will be separate incentives for “mild” and “strong” hybrid trucks if they are sold in sufficient quantity. There will also be credit for natural-gas–powered vehicles to match their reduction in greenhouse gases. Conversely, for CAFE purposes, oil burners are not penalized for the higher carbon content of diesel fuel.
Ethanol resumes to lose favor, and flexible-fuel vehicles will only receive extra credit when manufacturers present data proving how much E85 such vehicles actually burn in real-world driving. In most cases, that amounts to little or none, so sell your Iowa farmland now.
California, which usually goes its own way in matters environmental, has signed on to this fresh program, which eliminates the specter of carmakers having to certify, build, sell, and tabulate separate fuel-economy fleets for the Left Coast state. That’s most likely one reason why most car companies are not objecting to this fresh proposal.
Another one is the promise of a midterm evaluation of the program in the two thousand eighteen time framework about whether the 2022–25 aspects of this plan remain technically feasible, cost-effective, and saleable. In the unlikely chance that gasoline prices drop back below $Two.00 per gallon and customers go back to buying corpulent vehicles, there will be an chance for a rethink.
But even with these caveats, this plan presents major challenges to automakers. The chart above provides an idea of what the future fuel-economy landscape might look like. We showcase the target CAFE requirements for fifteen vehicles from today through 2025.
As you’d expect, most of the current models are generally at their CAFE requirements [shown in green], plus or minus an mpg or two. Puny cars are actually well above their required CAFE numbers, which offsets the large and high-performance cars that are not meeting their CAFE requirements [shown in blue].
But going forward, the chart turns blue very quickly for just about all classes of vehicles based on today’s fuel-economy spectacle. Even the smallest and most efficient cars fight as their CAFE bogey skyrockets about ten mpg every five years.
Among current cars, only the Toyota Prius—and similar smallish utter hybrids—can meet the projected two thousand twenty five standards. Efficient, modern, mainstream sedans such as the Hyundai Sonata will need to improve their fuel efficiency by about fifty percent by the end of the program. And it’s hard to see how a Mercedes-Benz S-class will get close to its two thousand twenty five CAFE target of 46.7 mpg, when even today’s S400 hybrid rates a mere 27.Five mpg.
Even permitting for the violates provided by counting some of the off-cycle efficiency improvements and numerous counting of electrified cars, meeting these two thousand twenty five targets will require radical switch in our vehicles. A few more transmission gears and smaller-displacement turbocharged engines just aren’t going to cut it.
If these standards remain in place, expect to see some degree of hybridization eventually spread through at least half of the fleet. Even however the regulations are footprint based, the formulas still encourage some downsizing, and we’d expect to see some of that as well. Ultimately, when it comes to large luxury cars, weight savings will be a must. Expect the S-class of the future to be constructed largely of aluminum, with enhanced weight savings coming from carbon-fiber parts such as fetish masks, trunklids and roof panels. Or it might be as radical as the Mercedes F125 concept.
In the end, there’s little question that the technology exists—or can be developed—to meet these standards. But even more certain is that such technology will make two thousand twenty five vehicles far more costly than today’s cars and trucks. Whether the increment will be tabulated using four- or five-digit numbers remains to be seen.
