The revised fuel economy ratings for the Ford C-Max aren’t the first time that an auto maker has been forced to backtrack on fuel economy claims – nor will it be the last unless meaningful reform is undertaken to ensure that fuel economy figures more accurately reflect the way motorists drive their cars in the real world.
The discrepancies between the EPA’s fuel economy figures and what consumers can expect stem from a number of issues. For starters, manufacturers are allowed to self-report their findings, with the EPA only auditing about 10 to 15 percent of the vehicles on sale in any given year. There are all kinds of tricks that auto makers can use as well. In the case of the C-Max, Ford used data from its Fusion Hybrid to determine the C-Max’s fuel economy, which lead to inflated ratings. While this may seem nonsensical to the outside observer, this is allowed under EPA guidelines, as the auto makers are only required to submit data for the volume model of any group of nameplates that use the same powertrain – even if they bear little to no relation to one another, as was the case here.
EPA test procedures also do not permit the use of ethanol. Across the country but particularly in emissions-conscious states, many pumps dispense gasoline with up to ten or even twenty percent alcohol, which significantly reduces mileage. The driving conditions used bear little resemblance to anything encountered in the real world. Tests are conducted on a dynamometer rather than on a real road, and 48.3 mph is considered “free-flowing traffic” on a freeway while city driving cycles use a barely-crawling speed of just 21.2 mph. Despite being utterly detached from reality, there is a good reason why the EPA fuel economy tests are designed this way. They aren’t meant to really test fuel consumption.
An article by Consumer Reports quotes one expert as stating that the tests
“…were originally designed to test emissions, not fuel economy. They wanted to test a variety of speeds and accelerations.”
CR’s own fuel economy tests revealed significant discrepancies between the EPA numbers and their own road test cycles, with the biggest culprits being small turbocharged 4-cylinder engines. These tend to do well on EPA tests, since the low speeds don’t require much boost from the turbocharger. By contrast, real world driving does require the turbo to work harder when driven at speeds above 21.2mph, which is how a car like the Lincoln MKZ, with a 2.0L 4-cylinder engine, can return 16 mpg in the real world despite being rated for 22 mpg by the EPA.
With gas prices edging higher and fuel consumption becoming a priority among car shoppers, fuel economy tests have become increasingly importance for shoppers. Consumers compare “em-pee-gee” figures like they would have once looked at 0-60 mph times or crash test safety ratings, and rely on the EPA numbers to make purchasing decisions. Automotive marketing types know this, it’s not unreasonable to assume that powertrain calibration has sometimes been designed specifically with the fuel economy testing procedures in mind. Being able to hit a “magic number” like 40 mpg highway is a marketing coup. But being exposed as unable to hit that number in real life is a tenfold embarrassment, as Ford and Hyundai both know.
The current regimen of fuel economy tests have clearly outlived their usefulness.If the EPA test really is designed to measure emissions rather than fuel consumption, then that’s a strong indication of how relevant their guidelines really are. The next step is, what should be done to bring them back to relevance? Can the EPA test process be reformed? Should there be an end to manufacturer reported figures? Or is it worth ignoring EPA figures from now on in favor of someone like Consumer Reports or even a self-reporting site like Fuelly?