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Real-World Gas Mileage Moving Away From EPA Ratings: Report

 
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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--but these days, it appears, your mileage may vary more than it used to.

According to a new report, the gap between rated fuel efficiency and the real-world gas mileage achieved by actual drivers is increasing.

In 2001, it notes, the average difference between rated gas mileage and actual results was 20 percent or less in the U.S. and 10 percent or less in Europe.

By 2012, that gap had risen to 35 percent in the U.S. In Europe, it was 25 percent in 2011.

Highlighted by Ford hybrids

The variation in real-world results against published EPA efficiency ratings has been highlighted by owner reports that the 2013 Ford C-Max and Fusion hybrids do not achieve their 47-mpg combined ratings.

The EPA is now investigating those cars, which appear to have electric motors that, under gentle acceleration, can cover much more of the EPA test cycles in all-electric mode than actual drivers would.

The latest Ford hybrid, the 2013 Lincoln MKZ Hybrid, offers more information to drivers on factors that affect gas mileage.

Most analysis for Europe

The report, From Laboratory To Road, was published this month by the International Council on Clean Transportation.

It looks at ratings and real-world results both in the United States and in the European Union.

The bulk of its analysis applies to European cars and drivers, using data gathered from fleets in Germany, the Netherlands, Switzerland, and the U.K.

It shows the steepest increase in 2007 and 2008, when several member countries switched to taxing cars based on their rated tailpipe emissions of carbon dioxide.

The report is careful to note up front that "nothing in this analysis suggests that manufacturers have done anything illegal."

But, it continues, the New European Driving Cycle test "was not originally designed to measure fuel consumption or CO2 emissions, and some features of the test procedure can be exploited to influence test results for those values."

Discrepancy between EPA gas-mileage ratings & real-world results,

Discrepancy between EPA gas-mileage ratings & real-world results,

Enlarge Photo

U.S. analysis using "My MPG"

Only four pages of the 88-page report apply to similar discrepancies in the U.S.

That analysis is based on variations in "My MPG" data submitted by users to the EPA's FuelEconomy.gov website starting in 2004, against the official EPA fuel efficiency ratings.

The report suggests that more study is needed on these discrepancies.

"For the United States," it concludes, "the data examined in the context of this paper are seen only as a starting point for future analysis."

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Comments (21)
  1. i think the real reason the disparity is greater is we now have more tools to track the mileage. Before gas was cheap and people had anecdotal evidence of "how far they could go on a tank" which was usually a summer trip where gas mileage was greatest and most never considered the 10-25% drop in economy during Winter.

    Then the Prius came along and all of a sudden tracking every mile driven became a habit for many that has grown as the choices for driving have exploded with EVs, EREVs and hybrids when computing TCO.

    there is simply a lot more awareness. as far as the discrepancy? its always been there. nothing will change the fact that some drivers will get 35 mpg in a Prius
     
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  2. Can't trust the foxes to guard the hen house. Better to use what owners are saying, and Consumer Report tests.
     
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  3. Unfortunately buyers currently use the EPA rating when making a buying decision. And some brands (like Ford) seem to have a greater variation between estimated figures and reality.
    So it seems the "buyer beware" still applies when using fuel efficiency data.
    Personally I chose a 2013 Ford Escape 2.0 Litre Ecoboost over a Mazda CX5 and a Subaru Outback and based on the EPA website's "My MPG" info it was a bad decision.
     
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  4. Ford, and now VW have put out commercials that boldly display how much more power their hybrids have compared to the "other" hybrids out there. Naturally, when driven without regard to efficiency, they none of them get advertised rated mileage. But, using the "tutor" displays, a person can learn to drive far more efficiently. After a while, it becomes a challenge to beat your best results. My worst tank in my Prius was over 40 mpg. Every other tank has been over 45, and my best was just over 59 mpg. It can be done, but not by a new-to-hybrid owner using their old driving habits.
     
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  5. Too bad you did not get a C-Max Energi! My first tank which took me over a 3500 foot mountain pass and 723 miles averaged out to be 77.9 MPG. 6 weeks later it was time to fill the tank, but this time I went over 1000 miles between fill ups and the MPG was 84.5!
     
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  6. Interestingly, electric vehicles actually get better mileage in reality than the EPA estimates. For instance, the range provided by the EPA for the Leaf or Focus is around 75 miles. In these cars, 75 miles it's usually the minimum and regularly drivers see 85 and beyond.
     
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  7. There's a small issue with your reasoning. The 2013 Nissan LEAF is actually rated at 66 miles EPA range for an 80% charge, and 84 miles for a 100% charge, averaging 75 EPA miles that are posted on the window, all using the EPA 5 cycle test.

    To date, only the LEAF and Toyota Rav4 use this averaging, which makes comparisons even more difficult to all the other cars which don't use EPA averaging. For instance, the Tesla Model S is rated at 208 and 265 on a full charge only.

    A Nissan LEAF will drive about 84 real world miles at 65mph indicated on the dash on a level, no wind, roadway with a new condition battery at 70F/20C degrees temperature and without any climate control (heater/air conditioner).
     
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  8. There is not much reasoning to have an issue with. I simply stated that real would experience with these cars exceeds the EPA results. You apparently agree with this.
     
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  9. Every day I notice the same thing. Most drivers don't know their vehicle will drive without their foot pushing on a peddle. Most of the time you can see a red light over 200 yards before you get there. STOP WASTING FUEL
     
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  10. Doug, you're right on. The question is how to educate drivers. Any husband (or wife) who has ever give "pointers" knows how hard it is even to educate loved ones. And I suspect the overall "culture" does not favor taking advice.

    As for the new Ford: it was heavily advertized as a hybrid with oomph so it should not come as a surprise that the people who bought one are going to gun it.
     
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  11. But people loves to have "fun". Driving is a "fun" activities for many people.

    Is rollercoaster a waste of energy? Are water parks a waste? How about disney world? What about Mountain biking? Boating?

    People do things that are "fun" to them. Some of them are crazy to my taste or completely a waste of energy/time to me but that is their right. So, why don't we give them the best option available.

    A Tesla S is still far more efficient than an average ICE even if you drive it like how you described.
     
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  12. So I tried to put in my data at "My MPG" for my Volt. It gave me an error and said that "the distance traveled was to great since last fill up."
    :)
    That tells me that the EPA has a basic lack of understanding when it comes to Plugin Hybrid Electric Vehicles.
     
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  13. Why HAVE a label now that we can have the real number. Simply send people to the "My MPG" data submitted by users to the EPA's FuelEconomy.gov website or Fuelly - http://bit.ly/tdisportwagen

    "The variation in real-world results against published EPA efficiency ratings has been highlighted by owner reports that the 2013 Ford C-Max and Fusion hybrids do not achieve their 47-mpg combined ratings.

    The EPA is now investigating those cars, which appear to have electric motors that, under gentle acceleration, can cover much more of the EPA test cycles in all-electric mode than actual drivers would."

    People are simply trying to understand what things are likely to cost. If we use proxies for cost, of course the proxies will ultimately lie.
     
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  14. If we could just do a away with quaint notions of privacy, we could arm all cars with smartphone types of technology, measure everything including how much fuel is put into each car, and use all of that data. Then the fuel efficiency of all cars would be absolutely known.
     
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  15. I'm getting better than EPA rated numbers on our 2013 Volt. I've been a Ford guy for a long time but Chevy really did it right with the Volt.
     
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  16. Me too Dan, and the Volt reports its information realtime to the web.
     
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  17. @ Dan,

    I am getting decent EV ranges on my Volt (2012). Generally better than the EPA rating. I typically get about 38-42 miles in EV range. 48 miles was my personal best. The worst ever was 31 miles with high speed (75mph+ cruising) and 28 degree weather and heater on.

    In gas mode, my best ever was 44 mpg. My worst ever was 36 mpg. But on average it about 39mpg. So, it matches EPA rating. I find it the mpg varies a lot (up to 1-2 mpg) between the Costco gas with 10% ethanol and Chevron's 100% gas. I have also used regular gas (by mistake from a family member) once in Volt and it dropped that tank average to about 36 MPG for trips that is easily 38 mpg.
     
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  18. Doesn't sound like much of an analysis on the US side. Two significant problems.
    1) "My MPG" is not used by many people and the people that do use it are probably not representative of the population in general. Fuelly might be slightly better.
    2) There doesn't seem to be any accounting or comment about the 2007 improvements in the EPA methods.
     
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  19. Our 2013 Ford Fusion "Energi" plug-in hybrid is getting 45-47 mpg per tankful in our usual driving. We are half way through the current tank of gas and it is getting 47.6 mpg. Since we bought it in early April, there has been no cold weather and very little super hot weather in Northern California where we live - could that be the big factor?
     
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  20. Does your "mpg" include the electricity usage or NOT?
     
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  21. "By 2012, that gap had risen to 35 percent in the U.S. In Europe, it was 25 percent in 2011."

    Does this gap include the car computer's overly optimistic reading?

    Many owners don't bother with the "manual" calculation of using the miles travels since last tank and gallons filled into the tank. I would say that most of them "trust" the computers on the car.

    There was an articla on trip where the Prius and C-Max's computer has shown an optimistic reading of 5-9%.
     
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