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Ford’s math on hybrid fuel economy; standing by the C-MAX EPA ratings, acknowledging large real-world variance

Raj Nair outlining factors affecting real-world fuel economy in hybrids. Click to enlarge.

At Friday’s event unveiling the new Transit commercial vehicle family for North America (earlier post), Ford’s Raj Nair, group vice president global product development, spent some time addressing the issue of the large discrepancy between real-world fuel economy results for the C-MAX hybrid and its EPA fuel economy ratings—47 mpg (5.0 l/100km) city, highway and combined—earlier highlighted in detail by Consumer Reports. (Earlier post.)

Basically, Ford is standing by the ratings as determined by the current testing protocols, Nair said, but added that “we absolutely agree with EPA that hybrids are far more variable in the test cycle compared to real world driving conditions in conventional vehicles. We are working closely with the agency to determine if any changes are needed for the industry relative to hybrid vehicle testing.

Nair highlighted as an example the delta between EPA ratings and Consumer Reports results for multiple hybrids in one of the CR tests. Click to enlarge.

Nair noted that the Consumer Reports testing also found discrepancies in between real-world testing and EPA rating for hybrids from other manufacturers, and singled out a 19 mpg variance on a Prius as one example. One of the issues with the Ford results, Nair suggested, is that the performance of the vehicles as designed lends themselves to more sprited driving. Combining a “lead foot” with environmental factors can lead to the wide swings in fuel economy results, he said.

There have been some questions raised about fuel economy, so it is important to note that we have designed our hybrids to drive exactly the same as all our other vehicles, with the global Ford DNA. A key part of that DNA is “fun-to-drive”. We could have detuned the vehicles to maximize fuel economy like some of our competitors have done, but it would have been at the expense of a fun driving experience. And this would have meant that you would not be to take advantage of the 54 more horsepower that the C-MAX provides over the Prius.

Ford next-generation hybrids offer increased performance and extended electric modes up from from 47 to 62 mph. Tremendous advantage in fuel economy, but it also makes them more sensitive to spirited driving as well as to environmental conditions. Quite a few factors can affect hybrid fuel economy, more so than regular gas engines.

Among the differences Nair spotlighted were:

  • Speed: the difference between 75 mph and 65 mph can produce a 7 mpg difference in fuel economy.

  • Outside temperature: a temperature difference 40 °F and 70 °F can result in a 5 mpg difference.

  • Vehicle break-in: the difference from 0 miles to 6,000 miles can be a 5 mpg difference.

When I drive our hybrids home from Dearborn to Ann Arbor, when I am using all of our coaching tools, I consistently hit the combined number. Unfortunately, that’s not the way I usually drive. So when I drive that hybrid the way I drive my Shelby GT500, I typically lose about 12 mpg. That can be the difference between maximizing the tools available, versus having a little bit of a lead foot like I do.

—Raj Nair

In its testing, Consumer Reports found the C-Max Hybrid delivered 37 mpg (6.4 l/100 km) overall, with 35 (6.7 l/100 km) and 38 (6.2 l/100 km) for city and highway.

Nair pointed out that some consumers are achieving results better than the 47 mpg EPA rating.



You get out of them what you put into them.

Perhaps Ford could offer a free or low-cost "fuel economy school" showing how to get the most out of their hybrids.  If people failed to apply the lessons, they would have no one to blame but themselves.

Dave R

Pointing out MPG differences can be very misleading here. They should be pointing out percentage differences.

And really - 5 mpg better after getting broken in? That's anywhere from 10-20% better depending on the starting fuel economy...


Could Hybrids and EVs have built in driving programs to help wild, uncompromising, uncouth, inexperience drivers to change and/or improve their driving skills?

The on board Black Box in passenger planes are used to detect pilots faulty, inefficient skills. They are fed back in ground simulators for corrective measures. Many modern planes have immediate feed back to inform pilots that they are not using the best technique.

It seems that more driver assistance will be required to reduce energy consumption, oil imports, pollution, accidents, damages, fatalities, car insurance cost, etc.

The 30,000+/year fatalities from guns and even more from vehicles is not very democratic?

Kit P

“lead foot”

There is a good reason not to buy a used car driven by a teenager. The principles of driving to get good mileage have been around for many years. I used to mount a vacuum gauge on the dash.

There is nothing wrong with hybrids per se. It is the idiots who buy them that do not learn how to take advantage of the principles that allow for good mileage.

This is why a friend of mine who is also an engineer dubbed it the Pious. It is about image not performance.


A friend has a Ford Fusion Hybrid, and it came standard with a continuous fuel/mileage readout on the dash. If drivers can't learn how to drive economically from that, there is nothing that will help. My friend said his driving style changed within a week.

Bob Wallace

Some EVs already have an "econ" mode in which acceleration rates are limited and regenerative braking is more aggressive.

If you're driving a Volt and your daily drive is going to be less than 40 miles you probably are going to be more willing to step on it. It's not like the wasted electricity is costing you much.

Same with a Leaf, not a big need to drive super-efficiently in order to save a quarter as long as you aren't pushing your max range.


"Could Hybrids and EVs have built in driving programs to help wild, uncompromising, uncouth, inexperience drivers to change and/or improve their driving skills?"

Ford offers "Mykey" in some of their vehicles, its a second key with restricted privileges that you hand to your teenager..


"MyKey®, another innovation from the company that introduced SYNC®, allows parents to limit speed and audio volume to encourage teens to drive safer and improve fuel efficiency
Harris Interactive Survey shows that many parents would allow teens to drive more often if their vehicle was equipped with MyKey – helping young drivers build road safety experience

MyKey debuted as a standard feature on the 2010 Ford Focus and is now a no-cost feature on nearly all Ford and Lincoln models

WASHINGTON, D.C., Jan. 26, 2011 – Ford Motor Company’s innovative MyKey technology is designed to help parents encourage their teenagers to drive safer and more fuel efficiently, and increase safety-belt use.

Ford’s MyKey feature – which debuted as standard equipment on the 2010 Ford Focus and is now standard on nearly all Ford and Lincoln models – allows owners to program a key that can limit the vehicle’s top speed and audio volume. MyKey also encourages safety-belt use, provides earlier low-fuel warnings and can be programmed to sound chimes at 45, 55 and 65 mph."


I laud Ford’s up front attitude on this, and buying a C-MAX and driving it spiritedly is better than buying a Shelby GT500.

But the first chart (factors affecting real-world fuel economy) stinks; it is not intuitive.

The second chart is much better and simply and clearly implies (IMHO) that the sacred Consumer Reports is biased against US automakers by implying Ford cooked the books.

I agree that knowing how to drive (up-shift ASAP and think ahead to minimize all braking,) can indeed be improved with a continuous and average fuel/mileage readout on the dash - just be charitable to those behind you.

When you get to the intersection just in time for the green, that guy behind you maybe just missed the left turn arrow.

Nick Lyons

Go to CMax is getting 39mpg real world (EPA says 47). Prius is getting 49+, real world (EPA says 50). Check out 33 2013 CMax owners report average of 39.4mpg (range is 34 to 47); 22 2012 Prius owners report average of 51.1 (range is from 44 to 64).

CMax just does not get 47 mpg without hyper miling. Prius owners get 50 mpg just by driving their cars. I test drove a CMax and couldn't get the on board mileage display to show anything approaching 47 mpg, even while driving at a steady 60 mph. I liked the car, but it's just not what it's cracked up to be.

Nick Lyons

For more info on Consumer Reports testing of 2013 CMax and Fusion, go to:

The likely reason for the disappointing real-world results is the interaction between the Fords' electric drive up to 62 mph and the slow highway speeds of the EPA test. A fully-charged battery at test start could skew the test results, since the EPA test is fairly short and the test might end before more gas consumed to recharge the battery.

Consumer Reports tests highway mileage by carefully measuring fuel flow at at steady 65 mph. CMax get 38 mpg in this test (compare to 43 mpg for 2012 Camry Hybrid and 47 mpg for Prius V). I'm looking for great highway mileage in our next car, and the CMax isn't going to cut it.


Nick, its just that the Prius automatically hypermiles for you.. whether you want to or not.

Nick Lyons

@Herm: Prius hypermilers can get way over EPA estimates. Drive a Prius normally and you get close to EPA estimates. Same is not true for the new Ford hybrids.

I'm convinced the new Ford hybrids, by design or accident, are gaming the the EPA mileage test. I expect Ford didn't cheat; they just took advantage of flaws in the test procedure that favor short-term all-electric highway driving at moderate speeds.

Another data point--at constant 65mph, per CR:

Ford CMax 38mpg
Honda Civic LX 47mpg (not the hybrid)

Ford is going to be on the hot seat for this until the EPA changes the test or Ford changes the numbers. The laws of physics have not been repealed, and a larger, heavier, more powerful car using a drivetrain quite similar to those found in the Toyota hybrids is not going to get better mileage in the real world.

Kit P

“I test drove a CMax ”

Gosh Nick, keeping an open mind and collecting information will get you labeled as troll at GCC.

“sacred Consumer Reports is biased against US automakers ”

CR is biased against over power cars with poor handling, blind spots, poor quality, and expensive frequent repairs. I do not think the rule out non-US automakers but Detroit sure is good and fleecing consumers. There are some over priced cars out of Europe that give Detroit a run for their money when it comes to junk. When I lived in Spain we owned what had car that was really underpowered. How ugly was it? However, the first panic stop where are lives depended on stopping hard in straight line resulted in falling in love with it.

Being a smart consumer, I read CR at the public library when ever I make a major purchase. Since that result in a large degree of satisfaction with what we buy. We do not have to buy big ticket items very often. I needed a washer, dryer, frig, lawn mower when we moved. Off to library to read CR. Arriving a Sear just in time for a sale (who knew?), the sales person showed be the top of the line washing and matching dryer, in RED! Out of my folder, I showed her a a piece a paper that said last years model which was a CR best buy was half the price in white and was in warehouse at half the price. Then she tried to sell me the marching dryer which was not a best buy. Why does a dyer have to match the washer CR asked. Out of my folder, I showed her a a piece a paper for a better dyer at $200 less.

Before I could whip out a piece of paper for the Frig, she takes me in back and shows me last years best buy in polished stainless steel that she can give me a really good deal on it. Then she tells me that a lawn mower was just returned. It looked like it had never been run, $75.

My point is that CR is helpful in making an informed and not emotional choice. Before buy I car the first stop is to the library to check CR to see if what they think is a good choice. Then rent the car to see if is comfortable during a long trip. When you go to the dealer, take a folder and tell the dealer what you want. Get up an leave at the first hint that extras include undercoating for $200.

Bob Wallace

I agree, CR is an excellent resource. CR is about value and value is often plain vanilla. Japanese car companies produced value long before Detroit figured out the need.

And Detroit only figured that out by losing a lot of market share.

Sears is a "bait and switch" pro. I've bought most of my appliances at Sears over the last 20 years and each time I have to battle the sales person who tries to get me to upgrade.


"Your Mileage May Vary"

I've have a 2000 Focus, in the summer I get better than EPA rating.


This Raj Nair guy is using the standard corporate mumbo-jumbo lawyer speak to hide the ugly truth that Ford was so eager to beat the Prius that they have not been honest.

Nick Lyons is correct, nowhere comes Ford close to explaining why Prius owners do get EPA mileage and CMax owners don't.

If this Raj guy says that he can get 47 mpg while using all on-board guidance systems, well then I can get 60 mpg in my Prius with no sweat.

My lifetime usage (measured from the fuel tanked, not the dash) now stands at 4.22 l/100 km (56 mpg) after 3.5 years. And I don't hypermile, but don't have a lead foot either. Highway speed is usually 105-120 km/h (65-75 mph). I accelerate faster than most other cars.

Kit P


"My lifetime usage (measured from the fuel tanked, not the dash) now stands at 4.22 l/100 km (56 mpg) after 3.5 years."

You are not very credible. First you so not seem to be aware that your Pious has an ICE. I suspect that there are just a few tanks of gas that were somehow not written down. Just human nature.

"I accelerate faster than most other cars."

Most people get to the next light faster than I do. It has nothing to do with my car.


Kit P,

53-56 mpg is pretty standard in the "pious" with no special effort. Now, you can drive it down if your a fool with a lead foot.

Oh, and Raj Nair was talking in standard corporate mumbo-jumbo lawyer speak.

Roger Pham

I agree with Anne regarding the actual mpg of the Prius gen III. My actual mpg calculated from fuel payment receipt averaged about 56-58 depending on the season and whether short or long trip, etc. I did not attempt to hypermile, although I was careful with the gas pedal and avoid sudden braking.

This bodes well for the actual mpg of the C-max, since it is a heavier, larger and a more powerful than the Prius that is capable of 57-mpg real-world driving, the C-Max should be capable of 47 mpg of real-world driving in the hands of either Anne or myself. The Prius and the C-Max have very similar technology. The Lithium-ion battery in the C-Max should improve energy recouperation efficiency somewhat.

The fact that the C-Max falls short of the 47-mpg EPA rating may have to do with perhaps suboptimal firmware programming, or something along that line. I believe that Ford can re-tweak the C-Max to deliver around 47-mpg real-world driving in the hands of careful drivers in the near future. May be the earlier batch have faulty programming.

Roger Pham

I must hasten to add further that the slightly optimistic odometer of the Prius of around 3% was accounted for by measuring actual GPS distance and take the percentage of difference. So, the Prius actual mpg was measured using gas station fuel meter and GPS-corrected driving distance.

Roger Pham

It is equally possible that there is nothing wrong with the current C-max's firmware programming, but the discrepancy in the rating was due to the Prius' rating of 50 mpg is done for the average driver,and 56-58 mpg for more careful drivers like Anne and I, while the C-Max 47-mpg rating is calibrated for more careful drivers like Anne and I, such that we would be able to get 47 mpg out of the C-Max as it is sold today.

At any rate, an EPA rating of 40-mpg is still very good for the C-max, consider the 188-very-willing ponies on tap and the larger interior and heaver weight.

Nick Lyons

@Roger: I agree 39-40mpg for the CMax is pretty good, considering the overall value proposition of the car. But then I wonder if I wouldn't prefer a diesel version with even better highway mileage and without the hybrid compromises in packaging. In other words, why not just get a Jetta TDI wagon for a similar price? According to, average real-world mileage is 38.4mpg, and highway mileage is significantly higher. CR measured 49mpg at a constant 65mph.


I'm expecting the Fusion Hybrid Energi to have highway mileage roughly equal to the equivalent VW diesel, but burn fuel that's 20% cheaper.  Local driving would need no fuel at all.

Nick Lyons

@E-P: The plugin Fords look great on paper, and I'd love to charge my car from our recently-installed solar panels. I do worry about packaging compromises and the high price.


The packaging IS compromised, but until there's enough volume to justify a Tesla-style design with the battery in the floor pan, it's the best we're going to get.

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