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Breast-Beating Over EPA Mileage Labels: Will Ratings Change?

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2011 Fuel Economy Labels

2011 Fuel Economy Labels

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Obviously, fuel economy will be an increasingly big deal in years to come.

The gas-mileage ratings of new cars and trucks must double (and then some) between last year and 2025.

But as two recent news events pointed out once again, EPA mileage ratings on the window stickers of new cars may not be what drivers get in real life.

Due to what the companies called errors in testing procedures, Hyundai and Kia overstated gas-mileage ratings on 13 different vehicles from the 2011 and 2012 model years.

The companies agreed to reduce those ratings and pay owners of the cars a lump sum for the extra gas they would buy and any resale-value reduction for the cars.

Ford, meanwhile, faces a combined lawsuit on behalf of owners saying that real-world gas mileage of its new 2013 C-Max Hybrid and 2013 Fusion Hybrid is nowhere near their 47-mpg EPA combined rating.

Our own experience, along with that of numerous owners and commenters, indicates that the C-Max Hybrid delivers average real-world fuel efficiency of 35 to 39 mpg, and the Fusion Hybrid sedan a few mpg higher--but still well short of the 47-mpg number.

All EPA gas-mileage ratings come with disclaimers that boil down to the famous line familiar to anyone who's ever seen an auto ad: "Your mileage may vary."

But while owners generally give carmakers a 10-percent margin of error, the Ford hybrids seem to miss the mark by far more than that.

So, too, did Honda Civic Hybrids in the early part of the last decade--which ultimately led the EPA to revise its "adjustment factors" for hybrid-electric vehicles to bring their window-sticker ratings more in line with owners' real-world efficiency.

Three factors combine to cause confusion about gas-mileage ratings.

2013 Ford C-Max Hybrid, upstate New York, Dec 2012

2013 Ford C-Max Hybrid, upstate New York, Dec 2012

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First, in 2009, carmakers were required to adopt a new and tougher "five-cycle" test routine for calculating EPA fuel-efficiency ratings on liquid-fueled cars, which they submit to the EPA for certification.

Contrary to some buyers' expectations, the EPA only tests 10 or 15 percent of all new cars itself. Instead, manufacturers self-certify and in general, the EPA only steps in if there's dispute over whether a car's rating matches real-world results.

That means that despite the new and tougher tests, there's at least theoretical opportunity for automakers to "game the system" and get away with it unless there's a consumer outcry.

Second, the corporate average fuel economy (CAFE) ratings used for compliance with the EPA fuel-economy requirements that will double by 2025 are based on outdated test cycles that haven't changed in three decades.

Those cycles don't reflect modern driving techniques, prevalent air-conditioning use, and today's average highway speeds of up to 80 mph--which can cut efficiency by one-quarter against a 65-mph speed.

So the widely-publicized CAFE average requirement of 54.5 mpg in 2025 actually translates to a window-sticker combined rating of 43.6 mpg--which is, for the record, lower than several of today's Toyota Prius hybrid ratings.


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Comments (12)
  1. Well, EPA needs a different cycle testing for PHEV/EREVs for sure. That is too easy to "game" the current 5 cycle testing with PHEV specifically tunned for the range and power required.

    Both Honda and Toyota's PHEV only go up to 11 miles to 13 miles electric. Just happens to be the distance of EPA cycle!
     
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  2. Gallons per 100 miles vs. MPG makes for more accurate comparisons when less than a gallon of fuel is used on the average 30 mile trip.

    At 55 MPG 1.8 gallons fuel is used to go a 100 miles. Round up to 2.0 gal /100 miles & get 50 MPG, vs. round down to 1.5 gal/100 miles & get 67 MPG. For low MPG vehicles a +/-0.1 gallon change in consumption has little impact in MPG.

    For comparison the average 25 MPG vehicle uses 4.0 gal /100 miles, but you can save a gallon every 100 miles at just 33 MPG. To save 2.0 gal /100 miles requires better than 50 MPG. First gallon saved requires just a 8 MPG increase, but to save a second gallon /100 miles requires an additional 17 MPG increase!
     
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  3. If we are going to do that, why not just switch to L/100km like the rest of the world, and be done with it?
     
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  4. From the article: "Obviously, fuel economy will be an increasingly big deal in years to come."

    This is not at all obvious to me. Electricity is already cheap and abundant. When battery prices come down, we'll see large SUV plug-ins. Fuel economy won't really matter.

    Bottom line: Efficiency won't solve the problem. We need alternatives.
     
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  5. Don't kid yourself MPG for ICE's (whether as the primary engine or ER generator) will still be important for some time to come. Pure EV's wont really come of age for the masses until major advances happen in battery capacity and charging speed. I hope it happens soon, but I haven't really seen those needed advancements anywhere.
     
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  6. "When battery prices come down, we'll see large SUV plug-ins"

    Actually, it is more than "price" to make it competitive.

    It has to be better in terms of energy/power density. More KWh per KG and more KWh per cm^3. It also needs better power per unit weight and volume. Of course, price has to come down as well along with all those factors. Recharging has to be fast and infrastructure has to be there.
     
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  7. What I haven't heard anyone discuss is whether ICE cars can get the fleet mileage anywhere near the new cafe rating. It seems that major weight reductions are about the only trick, beside really small cars, that can meet these goals (given that an ICE will never be much more efficient than they are today).
     
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  8. ...But when I wrote that EPA ratings are garbage and cannot be trusted, people here argued with me up and down.

    When I want to know what a vehicle's fuel consumption is, I look at the European test numbers, assuming the make and model I am looking at are identical. Those numbers have proved to be right no target when I drove the vehicles in question.

    Ditch EPA numbers; they are meaningless. If you want to know what the fuel consumption of a vehicle is, use the European numbers.
     
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  9. I am NOT sure I agree with you on that. It just seems certain brands/manufacturers are good at "gaming" the EPA tests. In my experience, GM cars are usually pretty accurate in reflecting their EPA numbers in real world. So is Mazda. Some of the Honda models (newer ones) are better than the older ones. Toyota is all over the map and heavily depending on the right foot. Chrysler trucks are usually pretty accurate as well. Nissan numbers are okay, but Infiniti numbers are usually questionable. All the Hyundai and Kia that I have ever driven are usually FAR below their ratings in my experience...
     
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  10. I trust the EPA Mileage Labels to be what they always have been. Wrong.
     
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  11. The second line of the article seems incorrect. Fuel economy is not required to double from 2012 to 2025. See the chart that shows year-by-year requirements. It's more like 50% increase and the absolute value is a function of vehicle footprint.

    http://en.wikipedia.org/wiki/File:CAFE_Fuel_Economy_vs_Model_Year_and_Footprint_with_2017-2022_Proposals.png

    This is just a Wikipedia chart - see the Federal Register for the latest, similar plot going to 2025. 2013 Prius has an "unadjusted MPG" of 70.63 - well exceeding the 2025 requirement. They go by the unadjusted values with CAFE.
     
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  12. @Jeff, you certainly right that it will depend on the footprint. I'd suggest that John is right though when he says that fuel economy needs to basically double. The link you put only shows to 2022.

    As noted in the article, the interesting thing to see is if the discrepancy between the label and the real-world diverges further with increasing fuel economy/technology.

    If possible, would anyone here be interested in having fuel economy labels generated based on their specific driving patterns?
     
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