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Is driving for maximum mpg worth the trouble?

Discussion in 'Gen 3 Prius Fuel Economy' started by WPWoodJr, Jun 30, 2009.

  1. wsbones

    wsbones New Member

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    I'm not sure oil comes from fossils. Are you?
     
  2. a priori

    a priori Canonus Curiosus

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    I don't know exactly the reason for the question, but it prompts a couple from me:

    Let's just say we don't know that oil comes from fossils. Does that make some difference? Do you think there is some indication that oil is something which is under current and constant creation within the Earth?
     
  3. F8L

    F8L Protecting Habitat & AG Lands

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    Are you an abiogenic believer or are you just playing semantics with the word "fossil"?
     
  4. F8L

    F8L Protecting Habitat & AG Lands

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    If you were mainly a freeway driver I could see the comparison making sense for sure. :)
     
  5. WPWoodJr

    WPWoodJr New Member

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    True, the amount of money saved increases directly as number of miles increases. The point I am making is that there are diminishing returns to driving for better fuel economy. Going from 35 mpg to 100 mpg you only save 1.86 gallons/100 miles under the assumptions in the blog post. Whereas going from 15 mpg to 35 mpg, as I did by going from a 1998 Audi A6 to a 2010 FFH, I save 3.81 gallons/100 miles without even changing my driving style.

    That said, my FFH mpg is now 46.2 for the current tank :)
     
  6. WPWoodJr

    WPWoodJr New Member

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    Not so, the in service date determines the tax year you claim the credit in. The purchase date determines eligibility for the credit. See the IRS web site for examples.
     
  7. donee

    donee New Member

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    Hi WP...,

    But with banks giving 2 % interest, hypermiling does better well up to about 60 mpg. Somebody driving a 60 mpg vehicle , can hypermile up to about 70 mpg with some practice. That is is a consumption improvement of 14 %. You ain't goin to get that interest, even from Bernie Madoff!!
     
  8. WPWoodJr

    WPWoodJr New Member

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    True, but the reason the chart is compelling is because it speaks to a range of mpg and miles per year that is normal in everyday life. Almost nobody drives enough miles per year to make 1000 mpg significantly better in absolute dollar terms than 100 mpg, so a chart showing that range would not be as interesting even though it would have the same shape.

    For example, if you drove 40,000 miles per year at 100 mpg you would use 400 gallons of gas. At 1000 mpg you would use 40 gallons for a savings (at $2.70/gal) of $972 per year. I saved over $1000 (400 gal) per year by trading in my 1998 Audi A6 which got 15-16 mpg for a Ford Fusion Hybrid which gets 35-45 mpg, and I only drive 10,000 miles per year.

    So, no tricks in that chart :)
     
  9. WPWoodJr

    WPWoodJr New Member

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    I want a 100 mpg car too, despite my chart ;)
     
  10. WPWoodJr

    WPWoodJr New Member

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    The post is not questioning the desirability of achieving high mpgs, its more about diminishing returns for slower driving and effort expended.

    To get 45 (Today I'm at 46 :) ) mpg in the FFH probably requires more careful driving than getting 55 mpg in a 2010 Prius. So my question about whether its worth it to drive 45 vs 35 mpg is more for FFH drivers than Prius drivers. For 2010 Prius drivers I might have to compare 60 to 45 mpg.
     
  11. WPWoodJr

    WPWoodJr New Member

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    I picked 35 mpg as a lower limit to exaggerate my point - you'd have to really try to only get 35 mpg in the FFH (except in winter I suppose). I suspect most people who drive "normally" in the FFH get 38 or so mpg in mixed city/highway.

    Also, the Fusion S may get 34 mpg on the highway but not anywhere near the FFH's 41 mpg EPA rating in city driving.
     
  12. patsparks

    patsparks An Aussie perspective

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    Move to the UK and you can have bigger gallons.
    Will that help?
     
  13. fuzzy1

    fuzzy1 Senior Member

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    I'm the type who prefers to view the chart like this (35 mpg marked in red, and graph extended to 100 mpg):
    [​IMG]

    [​IMG]
     
  14. timberwolf

    timberwolf New Member

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    As an added bonus the fuel is much more expensive, last week a litre of petrol was 100.9 pence (minimum), so an Imperial Gallon would costs approx.

    4.59 GBP = 7.48 USD = 8.68 CAD = 9.28 AUD.

    If the UK used the US Gallon the cost would be approx.

    3.82GBP = 6.22 USD = 7.23 CAD = 7.72 AUD
     
  15. Flying White Dutchman

    Flying White Dutchman Senior Member

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    Is driving for maximum mpg worth the trouble?

    --
    yes i like it.
     
  16. timberwolf

    timberwolf New Member

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    What is the measure of worth?
    Is it cost?
    Is it being a more observant driver?
    Is it being more relaxed even if you arrive a little while after a more aggressive driver?
    Is it taking satisfaction in winding up that tail gating car behind you by sticking to or just slightly below the speed limit? (once they get past you, you know the odds are that you'll drift up behind them at the next set of lights anyway).
     
  17. fred garvin

    fred garvin New Member

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    i turn the question around

    if i am at 45, i ask myself "someone is offering me "X" to mod my behavior to get to 55 - shall i take the payment?"

    in my case, at 20K miles/year and $2.50 per gallon

    this is a real world situation. i sold my chevy avalanche suv at 15 mpgs (long story, wife nixed me getting a motorcycle at 40 so the avalanche was my reaction) in favor of a used gen 1 that got 45 mpgs for me when i got in it.

    at 20K miles and 2.50 per gallon, that switch saved me $2,222 annualized.

    i was being "offered" another $202 per year to learn how to increase the mpgs from 45 to 55. i accepted.

    At $4 per, i was making $3,556 annualized avalanche over gen I at 45, and an additional $323 per year to improve to 55.

    in that the 02 prius cost me 13K in 05 and is worth 6K now, i spent 7K on the car, plus 2k maintenance (front pads, rotors turned, reg battery, and new oil pan (juffy lube!!!). 9K cost, about 9K saved in gas (at 45).

    so in a twisted way i have driven the last four and half years for "free" when compared to the avalanche ownership

    like most of us (and jeez i said most not all) i did NOT have a need for the 7,000 pound beast that was the avalanche
     
  18. Rokeby

    Rokeby Member

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    Numerically, there is always a reduction in % gained when the "step"
    is constant:

    30 - 35 is a 16.7% improvement
    35 - 40 is a 14.3% improvement
    and so on...
    50 - 55 is a 10% improvement, etc.

    While the gain lets say in dollars not spent -- and perhaps saved --
    steadily decreases at each step, I would argue strongly that the
    opposite is true for the sense of satisfaction, achievement, happiness,
    and even self-worth. It is an inverse relationship. It goes up more and
    more as each step is successively more difficult to achieve. We're
    talking about achievements at the top of Maslow's hierarchy here. This
    is where life, or at least a few minutes a day of life, is good indeed.
    This I think is "worth the trouble."

    It seems that the OP finds striving for the highest possible FE/MPGs is
    somehow a burden. It is as if the mental energy needed to be put to
    the task is sorely missed when taken from some other tasks.

    What might those tasks be?

    I would trust that we are not talking about those tasks necessarily
    connected with the safe and prudent operation of a motor vehicle such
    as:
    * observing traffic and road conditions,
    * estimating rates of closing and opening with other vehicles,
    * looking for incoming/crossing vehicles,
    * judging time and distances to stop lights and signs, speed bumps,
    * etc.

    In fact, when pushing for FE/MPGs well above the EPA estimates for
    any vehicle, you have to do increasingly better at being aware of and
    reacting to these conditions. For the most part, you are a safer driver.
    And this is not "worth the trouble?"

    So, the activities from which the increased effort must be diverted are
    something else that people do while driving. Those might include:
    * talking on a cell phone
    * text messaging
    * eating and drinking
    * shaving
    * putting on make-up
    * brushing hair
    * changing clothes
    * holding/petting a pet
    * disciplining children in the back seat
    * exchanging physical intimacies with a passenger

    These are things that you're not supposed to be doing while driving in
    the first place. If expending mental energies on getting better
    FE/MPGs and being a better driver results in a reduction or cessation
    of any these activities that surely is a good thing, and most definitely
    is "worth the trouble."

    The fact that you're also saving some doe-ray-me and polluting less
    are nice additional benefits and also "worth the trouble." :cheer2:
     
  19. WPWoodJr

    WPWoodJr New Member

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    Nice log-log chart which illustrates diminishing returns of high mpg! It shows that in going from 10 to 35 mpg you save 7+ gallons/100 miles, and going from 35 to 100 mpg you save just under 2 gallons/100 miles. If we could get everybody to 35 mpg it would be a huge win.
     
  20. WPWoodJr

    WPWoodJr New Member

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    True, the percent gained per mpg increased goes down. However even if you look at it on a constant percentage basis the law of diminishing returns operates. Going from 10 to 20 mpg (100% improvement) saves 5 gal/100m. Going from 20 to 40 mpg (100% again) saves 2.5 gal/100m. Going from 40 to 80 mpg saves just 1.25 gal/100m.

    In my case, I do get satisfaction out of driving for high mpg. But sometimes its not practical and sometimes passengers (eg wife) find it really annoying ;)

    Therefore its nice to know that getting at least 35 mpg or so gives a huge benefit; anything higher is gravy :)