Why mpg instead of gallons per mile or L/100km?

I think the compact would be the winner. My math assumes that you drive 12K miles per year:

Gallons of gas used by...

Minivan@20mpg: 600
Minivan@21mpg: 571
Gallons of gas "saved": 29

Compact@30mpg: 400
[email protected]: 369
Gallons of gas "saved": 31

Prius@49mpg: 245
Prius@55mpg: 218
Gallons of gas "saved": 27

However, if you stopped driving the minivan (@20mpg) and compact (@30mpg) and the Prius (@49mpg) each 12K miles for a total of 36K miles, or 1245 gallons of gas AND instead drove the Prius 36K per year, you would use 735 gallons @49mpg or 655 @55mpg for a savings of 510 gallons and 590 gallons, respectively.

Hmmm. Hope I did that math right!

 

When it comes to the average consumer, who cares? When you are comparison shopping, all you need is some sort of basis for comparison such as EPA estimates. We all know they are only estimates and your mileage may vary. Beyond that, once the car purchase is made, either you are going to drive it in way that gets you the best economy or you're not. People are shelling out HUGE amounts of money for autos these days and most are making payments that equal what a house payment should be. Having to think about an extra $$ or two at the pump is not going to matter, nor is the amount of miles they got on a tank.

Of course Obsessive Complulsive PriusChat drivers are exempt from the statement above. Which, by the way, is why I suppose you are making this topic. Right?

 

<div class='quotetop'>QUOTE(theorist @ May 24 2006, 11:47 AM) [snapback]260345[/snapback]</div>

It's all the same. As you said in your post, it's just a reciprocal, so the only difference is convenience, and that is dependant on your base. If you want to compare how far you can go on a given amount of fuel, then mpg is easier. If you want to know how much fuel it takes to go a given distance, then it's easier to have it flipped around, but not that much easier. It's only simple math.

Let's do something really creative, like measuring speed in furlongs per fortnight.

Tom

 

<div class='quotetop'>QUOTE(qbee42 @ May 24 2006, 12:48 PM) [snapback]260386[/snapback]</div>

Travelling at 174,720 furlongs/fortnight, I get about 907,200 rods to the hogshead, and that's the way I like it!

 

MPG is a 1/x equation. The higher MPG, the higher the diminishing returns.

 

I totally agree with unruhly on this. The average consumer couldn't give a rats nice person about it. To wit the 1/100% of total vehicle sales in NA is a hybrid with good gas mileage. And that will probably not change in the foreseeable future. Sorry

 

<div class='quotetop'>QUOTE(Skwyre7 @ May 24 2006, 11:20 AM) [snapback]260407[/snapback]</div>

Abe? Abe Simpson? Is that you? I think for a lot of people ignorance is bliss. Like Frank said, they don't give a rat's arse. That will change if gas prices continue to rise and stay very high.

 

According to my calculations I'm using 14 teaspoons per mile.

 

<div class='quotetop'>QUOTE(Sam-I-Am @ May 27 2006, 11:29 AM) [snapback]261809[/snapback]</div>

Ooooh, I like those units! The idea of teaspoons per mile is fun to visualize!
Using that calculator, I figure I get about 1 cup per mile in my truck.

 

<div class='quotetop'>QUOTE(Sam-I-Am @ May 27 2006, 12:29 PM) [snapback]261809[/snapback]</div>

Nice. I like that one too.

 

<div class='quotetop'>QUOTE(qbee42 @ May 24 2006, 09:48 AM) [snapback]260386[/snapback]</div>

It may be the same conceptually, but I don't think that means it doesn't matter how you do it, for a couple of reasons.

Doing a reciprocal may be a trivial bit of math, but that doesn't mean that people are going to do the math and see it both ways. People will tend to view things in the manner they were presented, and presenting them in MPG will hide the fact that going from 10 to 20 mpg is a HUGE savings in gas compared to going from 100 to 200. Over 10000 miles, the first one saves 500 galons of gas, the second saves 50 gallons. MPG really hides just how gas-guzzling the guzzlers are.

The other reason is when you start dealing with averages, some strange things can happen. For example, with the CAFE standards you have to maintain some average MPG, say 25mpg, or whatever. The problem is, average MPG doesn't exactly determine how much gas is spent over a certain amount of driving. You can have two scenarios, both where the overall average is 25 mpg, but in one scenario all cars either get 10 or 40 mpg (half each), and another scenario where all cars get 25 mpg. If we compare how much gas is spent driving 1,000,000 miles, they're different. (The first situation uses 62,500 gal and the second uses 40,000). Using GPM the you don't have that problem.

Personally I'd prefer to use GPM because it makes a statement about which is more important, the distance you want to go, or how much gas you have to spend. I'm distance-oriented. Really all I care about is how much gas I need to spend to go the distance I want to go. Using Mpg, on the other hand, is like saying "I have this tank of gas, how far can I go? If I don't use it all up going to where I normally would go, I'm gonna drive some more until it's all gone!" So it kind of frames the issue in terms of using up your gas, rather than saving it.




<div class='quotetop'>QUOTE(theorist @ May 24 2006, 08:36 AM) [snapback]260332[/snapback]</div>

So on Cartalk the puzzler they presented one week had even more dramatic numbers. It was something like 10mpg to 11 vs. 100 to 200, and the answer was of course that the 10->11 improvement saved more gas.

<div class='quotetop'>QUOTE(theorist @ May 24 2006, 08:47 AM) [snapback]260345[/snapback]</div>

I'd vote for GPKM, gal per 1000 miles. This way we'd get reasonable numbers (most current GPKMs would be between 10 and 100, and it only goes down to 1 when we hit 1000mpg, which is probably a long way off).