By on May 3, 2011

A lot has changed in the auto industry in the three years since I started writing here at TTAC, and one of the more heartening developments has been the move towards ever greater transparency for all kinds of data, from sales breakouts to incentives to sales-weighted fuel economy. Though I’d like to think that TTAC played a role in helping push towards greater transparency and disclosure, the real heroes of this story are Hyundai (which has begun to release its sales-weighted fuel economy each month and is moving towards quarterly fleet sales breakouts) and TrueCar, which has possibly done more to put information in the hands of auto consumers than anyone else (TTAC included). TTAC thanks everyone who is helping push the industry towards ever more disclosure, and invites you to take advantage of these newly-available data points in order to better understand the ever-evolving face of the US auto industry. Here we present TrueCar’s TrueMPG data for April, which shows a .2 MPG improvement across the industry since April 2010.

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16 Comments on “Sales-Weighted Fleet Fuel Economy For April...”


  • avatar
    BlueEr03

    I am a bit confused by the Ford data above. If the average car went up 2.5MPGs and the average truck went up 2.1MPGS, how did the company only go up by 1.9MPGs.

    I don’t see how it can be a mix issue because both cars and trucks exceeded the company average.

    • 0 avatar
      aspade

      Because a mpg isn’t a constant unit of measure. In fact it’s a terrible unit of measure that should be thrown away for gpm and the sooner the better.

      Pretend last year you sold one car that scored one mpg and one car that scored ten mpg.

      Your fleet average is 2 / (1/1+1/10) = 1.81 mpg.

      This year both of your products increase their scores one mpg.

      Your new fleet average is 2 / (1/2/+1/11) = 3.38 mpg.

      Which is 1.57 better than you did last year despite neither product improving that much.

      • 0 avatar
        musiccitymafia

        I had to think about this for a bit. Your formula says … if traveled exactly one mile each … the first car would use 1 gallon … and the second car would use 1/10 of a gallon … therefore over the 2 miles traveled a total of 1.1 gallons would be used … i.e. 1.81 miles per gallon.

        Seems misleading somehow as simple straight math says (1+10)/2= 5.5 mpg.

      • 0 avatar
        SP

        That’s a little odd … I wouldn’t call that an average MPG, per se … But I see where you are coming from. Your assumption is that each vehicle travels the same distance, rather than using the same amount of fuel.

        The simple way to do it would be to let each car use 1 gallon of fuel and then calculate the average distance each car traveled.

        (1+10)/2 = 5.5 mpg

        Or, next year,

        (2+11)/2 = 6.5 mpg

        So, since every vehicle increased its mileage by 1 mpg, the fleet average increased by 1 mpg.

        The calculation you are doing is certainly not the mean that most of us think of as “average.”

        I guess what you are doing makes sense if you want to measure consumption on a macro scale. But if you are going to convert to GPM in the middle of your calculation, then you might as well stay in GPM.

        But I don’t think an individual car buyer really cares about how much gas everyone else is using … so MPG is equally relevant as GPM to a car buyer. And consumers like to “get more for their money”, so MPG is a more natural metric in one sense.

      • 0 avatar
        aspade

        The harmonic mean is what the EPA calls average mpg.

        Which is a shame, because if it worked the simple way the greenbeans’ pie in the sky CAFE goals would be much easier to live with (i.e., work around.)

        I don’t believe working in mpg does consumers any favors. It drastically overstates minor differences at the high end of the scale and hides them at the low end.

        How many people know that the wallet hit between 12 and 14 mpg is larger than that between 40 and 75?

  • avatar
    TEXN3

    It’ll be interesting to see how much Subaru jumps next year with the FB20/CVT combo Impreza forthcoming. Especially since their fleet share very similiar MPG numbers across the board. Dump the turbo models and the average would only jump a few MPG. Add a vehicle, which will sell more of since it will finally be competitive on this front, with at least 10 mpg increase.

    I guess I’ll be interested, especially since Subaru’s lineup usually doesn’t have too many variables like larger companies.

  • avatar
    Z71_Silvy

    How could Ford trucks be LESS than GM when Ford has all of those so-called ECO boost engines running around?

    Oh…that’s right…they’re not ECO at all…juts a V6 that gets V8 mileage.

  • avatar
    SV

    How are Toyota’s small car ratings so much higher than everyone else’s? The Corolla may get amazing gas mileage in the real world, but its EPA ratings are nothing special.

    • 0 avatar
      Rada

      I get about 35 mpg, about 2/3 town and 1/3 highway driving combined on a 2003 Corolla. Went down 1 mpg after our gas stations went E10.

    • 0 avatar
      CJinSD

      Just a guess, but maybe whoever is categorizing the cars is counting the Prius as a small car.

      • 0 avatar
        SV

        Ah, the Prius would definitely explain it. I’ve always considered the current generation more of a midsize (it’s pretty roomy) but I guess the EPA/CAFE/TrueCar/whatever doesn’t.

      • 0 avatar
        Steven02

        SV,
        The Prius is definitely the reason and TrueCar is doing the ratings. The Prius is midsize by the EPA, but so is the Cruze. The Accord Sedan is a large car by the EPA. It really doesn’t make sense for these cars to compete in those brackets because they are on the bottom end of the sizing comparison. That is why the Cruze and Prius are considered small and the Accord midsize.

  • avatar
    SVX pearlie

    It is interesting that fuel economy is an inverse of transaction price.

    If Hyundai could have GM’s industry-highest transaction prices, at the expense of their current industry-leading mileage, I’m sure they’d take it.

    • 0 avatar
      Steven02

      Hyundai doesn’t sell trucks. Hyundai also doesn’t sell as many large SUVs/CUVs as GM.

      It is really a pretty simple equation. The bigger the vehicle, the lower it costs, the worse fuel economy it gets. If Hyundai sold more Genesis and Equus models, then their fuel economy would go down but transaction price would be up. I am guessing they are happy where they are with the products they have and the mpg ratings that they have.

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