Breast-Beating Over EPA Mileage Labels: Will Ratings Change? Page 2

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2011 Fuel Economy Labels

2011 Fuel Economy Labels

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Third, two-thirds of U.S. drivers don't understand that gas mileage is a non-linear scale: Improvements on the high end actually reduce fuel consumption much less than do improvements on the low end.

(Here's the math: Over 100 miles, improving from 10 to 20 mpg saves 5 gallons of gasoline; the "same" 10-mpg boost from 40 to 50 mpg saves just 0.5 gallons over the same 100 miles.)

This all adds up to a mess.

The stakes get higher when you realize that the EPA itself says a 2025 car will cost $2,600 more in real dollars than a 2011 model if carmakers choose the most cost-effective routes for boosting gas mileage.

Carmakers we've spoken to scoff at that estimate, saying the real cost might be double that--although crying wolf is a not-unknown tactic among auto engineers who (understandably) tend to dislike new rules in general.

This has all reignited debate over whether the CAFE and EPA window-sticker gas-mileage testing should be modified or updated.

It's always possible; the 2009 switch from "two-cycle" to "five-cycle" testing for gasoline vehicles added three more rigorous tests to the well-known "city" and "highway" ratings.

And such changes are more procedural than public.

President Barack Obama may have joined the head of the EPA to announce the new 2017-2025 CAFE requirements for 54.5 mpg.

But the rules and details of how those numbers are calculated are negotiated by government rule-makers and automotive engineers on the compliance side and rarely make it into the news.

Still, we can't help but be pessimistic that anything meaningful will change. So we can only leave you with the famous words, once again ..

"Your mileage may vary."


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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!

  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!

  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?

  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.

  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.

  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.

  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).

  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.

  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...

  10. I trust the EPA Mileage Labels to be what they always have been. Wrong.

  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.

    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.

  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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