Should EPA Gas-Mileage Ratings Tests Change? What You Need To Know

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2013 Ford C-Max Hybrid, Catskill Mountains, NY, Oct 2012

2013 Ford C-Max Hybrid, Catskill Mountains, NY, Oct 2012

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Your mileage may vary.

We've heard it for years, we all know it's true, and yet we put our trust in the EPA's fuel-efficiency ratings as a guide to what kind of gas mileage a car will really get.

Now, two cars--the 2013 Ford C-Max Hybrid and the 2013 Ford Fusion Hybrid--have brought the failings of the EPA test system to the fore.

10-15 percent leeway

In general, buyers seem comfortable with variance of 10 or 15 percent from the advertised EPA ratings.

And although automakers generally publicize only the higher rating number (for gasoline cars, always the highway cycle), the EPA's combined rating is usually pretty close to real-world fuel economy for most buyers--within that margin.

But the new 2013 C-Max and Fusion hybrid models have generated a drumbeat of dissatisfied buyers, who claim their real-world mileage doesn't even come close.

Inevitably, there are now lawsuits.

'What was Ford thinking?'

Here's just one of many comments Green Car Reports has received on the topic:

OPEN LETTER TO FORD: I thought my 2013 C-Max would be a Prius killer. NOT! As a returning Ford buyer, I feel deceived. I want to support U.S. companies and U.S. jobs.

What was Ford thinking when they published 47/47/47 estimates? Based on the advertised EPA estimates, I would have been OK with low 40s, but 28-33 mpg is not even in the ballpark.

This is not an issue about EPA testing standards, but rather an issue about setting false customer expectations in order to promote sales.

Ford's "47MPG" marketing campaign tarnished what should have been the rollout of a truly remarkable vehicle, the C-Max. Real-world MPG estimates should have been promoted in the mid-30s.

2013 Ford Fusion Hybrid

2013 Ford Fusion Hybrid

Enlarge Photo

Only EPA estimates allowed

We've gotten dozens of comments like this, following our coverage of the disparity between published 47-mpg combined EPA ratings and real-world figures achieved by drivers.

There's just one problem: The writer above is wrong, in that this IS actually an issue about EPA testing standards

That's because the only fuel-efficiency figures any carmaker may use in their advertising are those derived from the standardized EPA testing cycles.

Carmakers can commission independent studies--VW did just that to show its VW Jetta TDI diesel outperforms its EPA ratings--but they can't quote those results in their ads.

And that brings us back to the question that Ford has highlighted: Are the EPA test cycles flawed?

EPA mostly on target

The answer seems to be that for most cars, they're essentially on target.

They were last changed in 2007, to reflect real-world results achieved by owners of Toyota Prius and Honda Civic Hybrid vehicles.

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Comments (23)
  1. What, no mention of Hyundai/Kia and the fact that Ford might be bending the truth?

  2. We may see the C-Max numbers come up a little now that the weather is warmer.

  3. As the owner of a Gen1 Honda Insight hybrid with a lifetime > 77mpg, I know that exactly HOW one drives a car is the greatest variable - hopefully, there is not much leeway in this when conducting the EPA testing.

    If they haven't already, there are two factors EPA should control or standardize:

    1) Regeneration influence in EVs and, to some extent, hybrids. The smug satisfaction of driving an EV down a long hill and watching 'fuel' gauge go UP is priceless.

    2) Electric Vehicle mileage is horrendously influenced by energy-robbing non-motive variables such as heating and aircon. These should be excluded from any testing and mileage reporting because they are uncontrolled variables; specifically, heating and/or aircon should be turned OFF.

  4. I couldn't agree more about the downhill in an EV. I basically go downhill all the way to work (about 7 miles) and I arrive with 1-3 miles more than when I left. #2 though is only part of the testing I'd like to see. I'd like testing done with and without HVAC, as well as an adverse test (raining and windy). That way we can see the range from a best case and worst case scenario.

  5. Agreed -- we need an adverse test. I'm amazed at how much energy the windshield wipers seem to suck up in my 2012 Leaf -- add headlights and some defog and you'll be lucky to get 50 miles on a full charge of a new battery.

  6. Does Ford walk away without blame here? I think Ford is basically using a trick to ace the test. They start the test with a full battery which is significantly drained during the test (it can go all electric at high speeds) allowing the vehicles to end the test at peak efficiency, right before it's time to pay the piper: a period of much lower efficiency when the battery is replenished. Result: the test doesn't show all the energy that was used during the test cycle.

    Not sure if the test cycle just happens to work in Ford's advantage or that Ford also tweaked the software a bit to exacerbate the effect but if more energy from the battery was used than replenished during the test than making a big deal of the EPA rating is very misleading.

  7. I think that's what the letter-writer was trying to peg them for. Ford should have known the EPA result was skewed, and instead of shouting it from rooftops as the God-given truth, put in moderate-size print with a very big asterisk. It does not excuse the EPA tests for being inaccurate to begin with.

  8. @Chris O: I'm not aware that Ford is doing anything different with its hybrids and their battery pack than Toyota, Honda, Hyundai, or any other hybrid maker.

    I'd be more inclined to say that because Ford's electric motor-generators are far more powerful than Toyota's, they can cover far more of a low- to medium-load cycle without kicking on the ICE.

    The way many people drive, though--as Joe S points out above--demands so much power that the powertrain blows right through the e-motor's max and kicks on the ICE. That's my supposition.

  9. @ John Voelcker: It's like you said: Ford can stay in EV mode at much higher loads than its competitors so yes: Ford is doing something differently than the rest. High loads mean high battery drainage and it seems unlikely the battery could be fully replenished during a short test cycle.

    Ford will try to pin the blame on the consumer of course by accusing them of having a lead foot, but in that case at least a fair share of (hypermiling) drivers should have results close (or even better) to the EPA results. I wonder if that's the case; it might be physically impossible to achieve the EPA results over a longer distance if the results don't reflect all the energy used during the test cycle.

  10. There are some folks getting at or pretty close to EPA according to the forum. However, to achieve it they are driving either much slower than normal and/or using entry level hypermiling techniques to do so. So it can be done but it takes an awful lot of work. The same techniques employed in a Prius would result in 60+mpg average or 40+mpg in a regular Civic.

  11. Here's what this says about the EPA tests: They've found tests that, in gas cars, coincidentally produce the same results as actual driving, but are not the same as actual driving so the results come back differently in hybrids. If they were behaving like actual scientists, they would take this as a sign that their test was invalid (i.e., not measuring the quantity they purported to be measuring) and redesign it. Adding adjustments after the fact to fudge the numbers would be considered scientific FRAUD in any other field.

  12. I think we have a case of "don't hate the player, hate the game" here.

    Ford "gamed" EPA testing so does other automakers. Toyota and Honda both gamed EPA testing by purposely choosing their plugin to be just enough to meet the 11 mile test cycle of the EPA test. But those are all cases of automakers exploring the rules.

    Kia/Hyundai just manipulated the numbers outright. That is flat out cheating.

    In the case of Ford, it is EPA's fault for having an old test condition that allowed the system to be explored.

    One way to "fix this" is to increase the EPA test to 25 miles or longer. Increase top speed to 70mph (the max speed allowed in many interstate hwys) and require the hybrids to complete all 5 cycles with a 50% drained battery.

  13. Both of our Toyota Hybrids, and my previous Camry SE, get well within and better than the EPA sticker mileage. So maybe it's only Ford's test that needs to be looked at.

  14. I think the main problem with the EPA test is that the Highway portion does not include a significant amount of constant high speed travel. When a hybrid car generates an EPA highway number that is greater than that vehicle's steady state 65mph MPG, something is wrong with the test. I think the Ford cars are basically running the test like a pulse and glide hyper-miler, which does not reflect what most people consider to be highway driving. A conventional gas car will generate a lower MPG result on the test than its 65mph constant burn rate, while the Ford hybrids clearly exceed it.

  15. Exactly! You nailed it. In fact, the EPA hwy and high speed test cycles average LESS than 50mph. That is a SHAME!

  16. "Ford's "47MPG" marketing campaign tarnished what should have been the rollout of a truly remarkable vehicle, the C-Max. Real-world MPG estimates should have been promoted in the mid-30s."

    I just wonder how much longer will Ford's management be able to pretend Americans do not want diesel cars. Say, how long can a manager keep their head where the Sun does not shine?

  17. But American's *don't* want diesel cars! :)

  18. Is that why diesel sales have been constantly growing in America, at a minimum rate of 25%, year after year, because "Americans do not want diesels"? "You have been living in the dream world, Neo."

  19. Since you asked, the last time I drove 55 on the freeway was about a week ago. Not because of a traffic jam. I usually like to drive the speed limit - much to other driver's annoyance. But if I get behind a truck going up a hill, I don't try to zoom around. I back off the cruise control and keep my distance. I've actually compared drive times when I do the more popular 75 to 80 and when I do about 60 to 65. Guess what? It almost makes no difference in my 17 mile drive to work. And I get to work a lot less frazzled. The only thing you have to do is ignore the tailgater in the rear-view. But you get those even if you do 80, so not much difference.

  20. Last time I drove 55? Yesterday, in a 65. Just for the gas mileage in my civic hybrid (the bad year)

  21. It's a funny subject now. I've had Toyotas since around 1977 now, on and off. In our household, we have a 2007 Camry Hybrid, and I just recently purchased a 2013 Prius V hybrid. The 2007 Camry HB get an average of 36-37, while my brand new Prius V has obtained a 42 MPG average through 700 miles.

    Both are either over or equal to the stated combined mileage figures.

    Enter Ford. All of a sudden, everything must be redone. Why?

    Because Ford's claimed 47 mpg COMBINED is preposterous?

    I've obtained the average in all of my cars for decades. No problems. Now a brand new Toyota 2013 car, same thing. Is Ford's marketing/media machine really that powerful?

  22. @Steve: It's not Ford's "marketing/media machine" that's the issue. If you read the whole piece, it's that Ford appears to have designed its latest hybrid system so that it stays in electric mode MUCH more on the EPA test cycles than it does in most real-world use.

    And as we note in various coverage, everyone seems fine with a 10-percent variance from EPA combined rating (45 mpg instead of 50 mpg in a Prius, for example). But the real-world ratings obtained by many, many Ford owners vary far more than that: 20 percent or more.

    Ford is legally allowed to advertise ONLY the EPA ratings, but those ratings vary far MORE from real-world results than they do for other makers.

    THAT'S the issue.

  23. I've monkeyed around with driving different speeds and never in my long life have the EPA estimates been close to what the real gas mileage is. I'd like to have them confirm they are also testing with ethanol 10 gas because that lowers the mileage. What a joke. I'm glad there are lawsuits for this very reason.

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