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2 In 3 Misunderstand Gas Mileage; Here's Why
thecarchik sends in this piece, which was published last March but remains timely: "OK, so here's a little test: Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg? If you're like most Americans, you picked the second one. But, in fact, that's exactly backwards. Over any given mileage, replacing a 10-mpg vehicle with one that gets 20 mpg saves five times the gasoline that replacing a 33-mpg vehicle with one that gets 50 does. Last summer, Duke University's Fuqua School of Business released a study that shows how much damage comes from using MPG instead of consumption to measure how green a car is. Management professors Richard Larick and Jack Soll's experiments proved that consumers thought fuel consumption was cut at an even rate as mileage increased."
I don't know if changing the units will help much ..
I get that the 1st one is a 100% increase while the other is only 50% but you still get a better deal and less pollution by buying the 50 mpg car (if the price is the same).
So which saves more gasoline? the 2nd one ...
Breaking: In an astounding fit of partial international cooperation and scientific rationality, the US adopts a mostly metric measure of resource use: the milliliter per mile, or the mlpm
For example:
10MPG = 378 mlpm
20MPG = 189 mlpm
33MPG = 115 mlpm
50MPG = 76 mlpm
90MPG = 42 mlpm
The unit is linear, easy to understand, with numbers everyone can grasp (40-400 ish), and most important, it slowly creeps the US mind toward the metric system, one small step at a time! What a breakthrough! When the cars fly, we can try for using km, not miles.
Also, mlpm helps put the idea that gasoline is a great resource, to be used sparingly, by the milliliter, as opposed to "by the gallon" like 7eleven slurpies.
Sadly, in all seriousness, from TFA "Consumption instead of mileage? Nah. Dumb idea. Never work. [sigh]" Probably have to agree with this. Not because it's a dumb idea, but because Americans with the social and business systems in place have shown repeatedly that they will hold onto current ideas so strongly even in the face of overwhelming and obvious evidence showing them to be wrong. Only the real American idol will effect real change in the US system, the dollar.
I always thought that measuring it Euro-way - in, for example, gallons per 100 miles - would me more practical and clear.
Though it may not be obvious why to someone in a metropolitan area or Europe.
MPG is the more useful number when you need to figure out what the range of a vehicle is (and perhaps if you'll be able to reach the next station). In the western US it's not unheard of to find yourself 100 miles from any gas station.
"Prefiero morir de pie que vivir siempre arrodillado!"
Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg?
people answer incorrectly because the question is academic. what matters is that people know a higher MPG is better, which i think almost everyone does.
If you go from 10 to 20 mpg, youre still less than the 33 mpg lower limit in the second case, so the second option "saves more gas". If the question is "which is a bigger improvement in fuel economy", then the answer is the first one.
In fact, the two cases are not interchangeable. Suppose the problem is dressed up a little: you have two cars that you use on a regular basis (this is not negotiable), but only enough money to replace one of them. One car gets 33MPG, and the other gets 10MPG. If you replace the 33MPG car, you can get a 50MPG vehicle. If you replace the 10MPG, you can get a 20MPG vehicle. Which would save more gas, replacing the 33MPG car or the 10MPG car?
Palm trees and 8
How much fuel is saved by replacing a vehicle that gets 10 MPG with one that gets 50 MPG?
It's the wrong question.
The question should be which one uses more gasoline...
two cars. one uses 20 mpg. the other uses 50 mpg. which one spends the most on gasoline for, say 100 miles.
Privacy is terrorism.
Don't get me wrong, if you're looking at replacing a perfectly good car with a new car, knowing how much better that car is is compare to your old car is a very useful thing.
That said, if you need a new car anyway, it really doesn't matter that the difference between a 10 mpg car and a 20 mpg car is higher than the difference between a 50 mpg car and a 33 mpg car. I 50 mpg car is still the best choice. No you probably shouldn't throw out your 6 month old 33 mpg car to get a 50 mpg car, and no you shouldn't say "I can't afford the 50 mpg car so I'm going to stick with the 10 even though I can afford the 20", but while mpg doesn't scale linearly, 50 is still better than 33.
Not everything needs to be stickered to the damn car...
True, but the poorly written blog was summarizing a study that showed that multi-vehicle families tended to use MPG incorrectly when choosing what car to upgrade. I'm not convinced that re-labling MPG to G/100M would solve the problem, but bringing attention to the misconception is worthwhile.
... I'm sure you friendly neighborhood car salesman would be happy to give you the sheet that explains all this information about the car too.
I'm pretty sure he's the last guy you should trust as his interest is that you buy a car from him, preferably the one that maximizes his commission.
Some privacy policy Slashdot.
It is, in countries that use the metric system. Better still, there is only one definition of "litre" worldwide.
Even if you had gallons per 100 miles or whatever, the question still exists as to "which" gallon. The answer is implied from whether you are a car manufacturer (your gallons are bigger) or a user (your gallons are smaller).
The US should also adopt L/100km, rather than, as TFA suggests, Gallons/100Miles. Seriously, if they're going to switch the measurements anyway, it makes more sense to switch to metric, like most of the rest of the world already has, than to retain the imperial system.
By reading this signature, you hereby agree with the content of the above comment.
I don't see here what the "misconception" is with the actual mpg figure. It works exactly the same as km/l, just on an inverted scale where bigger numbers are better. I initially chose the 10mpg to 20mpg here because it's basically doubling efficiency (but it's still shit), then wondered if there was some kind of trick to the question, ie what they actually meant by the wording.
Obviously having a 33mpg and switching to 50mpg is still the better scenario because you're wasting a lot less money per mile (on fuel at least) than the 10/20mpg scenario either way! You are still "saving" more gasoline in absolute terms than the person in the 10 to 20mpg scenario, even if you are not in fact doubling your efficiency - because you aren't using as much fuel to start with. The relative increase in mileage is a stupid thing to care about - overall mileage is king here.
which is totally what she said
But when I bought my last car, I looked squarely at the L/100km measurement. I did the math. And I realized that for what I'd save in the ticket price between buying a 2007 Chev. Aveo (which I did end up buying) over buying something like a Smart car or a hybrid, I could pay for the total gas I'd use over the entire lifetime of the car. The difference between 6L/100km and 3.8L/100km just isn't *that* significant, and certainly isn't significant enough to justify spending another $15,000 on a car that probably won't see 100,000km in its entire 5 year lifetime before I trade it in for a new one. The price of gas would have to be 7x what it currently is for that to have become an economical proposition.
The choice for an Hybrid or a fuel efficient car should not only take in to account the cost of the fuel, but also the cost to the environment. If you add the cost of a "carbon fee" for the extra fuel you burn, for the energy required to bring that fuel to you, the damage to the environment to extract that fuel, you get quite a good deal...
Here in Australia, they label most electric appliances with a sticker in the shops that shows you just how much energy it consumed compared to other similar alliances. It's not perfect, but it's a start in the right direction, and it has been running for a long time.
One of the really crazy aspects of this system is the units used. You couldn't expect a normal person to understand "Watts" or "kW", so I've seen air conditioners labelled in "kWh per hour". As in "kiloWatt-hours per hour". I wish I took a photo.
One of the things we get right is how we label fuel consumption: litres per 100 km. Half the number means you use half as much fuel to drive the same distance. Twice the number means twice as much fuel to drive the same distance.
It's not exactly rocket surgery.
Here's a hint. If you wish to appear intelligent, rational, and adult, then when someone accuses you of not being one or more of those things, don't fly into a profanity filled rage. Everything lumpy says is true. It is indeed stupid not to embrace the metric system, and our education system has proved itself incapable of getting people to switch. You shouldn't even be angry at lumpy for pointing out the blindingly obvious, I don't find his phrasing insulting at all. He isn't saying we can't embrace the metric system, or that we are universally stupid. He is saying that we choose not to embrace the metric system, and that is stupid.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Why is the US so stubborn about adopting the International System of Units? Even the country where the "Imperial" units come from did. And while we are at it, why not adopt iso 216 and be done with silly sheet sizes?
Artix
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