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2 In 3 Misunderstand Gas Mileage; Here's Why

kdawson posted more than 4 years ago | from the bad-at-math dept.

Earth 1042

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."

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1042 comments

3 people in 2 don't know math. (4, Funny)

Tumbleweed (3706) | more than 4 years ago | (#32503188)

News at 11!

Re:3 people in 2 don't know math. (3, Interesting)

Fluffeh (1273756) | more than 4 years ago | (#32503356)

Yup, the average person is mathematically still an infant (or has forgotten all they learned and reverted back to infancy).

What they need to start doing is standardizing how they mark vehicles fuel consumption. Here in Australia, they label most electric appliances with a sticker [energyrating.gov.au] 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.

Perhaps they could start doing something like this with cars?

Re:3 people in 2 don't know math. (1)

Idiomatick (976696) | more than 4 years ago | (#32503424)

We have that too but the rating system is actually a meaningless scam. They give the sticker to whoever pays them enough. Having a governmental system would make sense but then that'd never fly in America.

Re:3 people in 2 don't know math. (1)

tumnasgt (1350615) | more than 4 years ago | (#32503480)

New Zealand does just that on all cars being sold at dealers that were made after 2000 and have the information available (NZ has lots of used imports from Japan, so the fuel consumption isn't always published).

See here [fuelsaver.govt.nz]

Re:3 people in 2 don't know math. (1)

Mike Buddha (10734) | more than 4 years ago | (#32503484)

In the US, for large appliances, they label the devices showing how much money per year the device costs to run, with a typical usage at a typical price of energy. I think it's a good system, because if there's anything we 'mericans respond to it's cold, hard cash.

The labels also show where the device is in terms of all the other devices in their class on an index, so you can see what the cheapest and the most expensive are in relation to the one you're looking for. This is only for large appliances, though (fridges, dryers, air conditioners, stoves, etc).

Re:3 people in 2 don't know math. (2, Funny)

fishexe (168879) | more than 4 years ago | (#32503588)

But only seven fifths of people have trouble with fractions...

Solution? (2, Insightful)

aliquis (678370) | more than 4 years ago | (#32503194)

I don't know if changing the units will help much ..

Re:Solution? (4, Informative)

Tuidjy (321055) | more than 4 years ago | (#32503256)

In Europe, or at least every country I've lived in, people measure fuel consumption in Liters-Needed-For-100-kilometers. I think that it works better than the way we are doing it here in the US.

Re:Solution? (5, Insightful)

selven (1556643) | more than 4 years ago | (#32503260)

Yes, changing the units will most definitely help. The units we should change to are the ones we already use here above the border: liters per 100 km. Going from 20 L/100k to 15 L/100k saves just as much as going from 10 L/100k to 5 L/100k. In most people's lives, the distance you need to travel is constant, not the amount of money you have to spend on fuel, so fuel per distance is much more logical anyway.

Re:Solution? (5, Funny)

Anonymous Coward | more than 4 years ago | (#32503434)

True, but you're one of those people who want to use the metric system and hate America, so I won't listen to what you say.

Re:Solution? (1, Insightful)

Fluffeh (1273756) | more than 4 years ago | (#32503446)

Yes, changing the units will most definitely help. The units we should change to are the ones we already use here above the border: liters per 100 km. Going from 20 L/100k to 15 L/100k saves just as much as going from 10 L/100k to 5 L/100k. In most people's lives, the distance you need to travel is constant, not the amount of money you have to spend on fuel, so fuel per distance is much more logical anyway.

*sigh*

Yes, the number of liters of fuel saved IS indeed the same, but going from 20L/100 to 15L/100 is a 25% reduction in fuel consumption, going from 10L/100 to 5L/100 is a 50% fuel reduction.

While your overall statement is correct, your arguments behind it seem either a little flawed or vague with direction. It is like selling an item that says it will save you 1 liter of fuel per 100kms. It has no context in how much fuel that will save, as it doesn't say how much fuel you use. Will it save 1L in a normal car? Will it save 1L in a lorry? Will it save 1L in a road train?

Re:Solution? (1)

PhunkySchtuff (208108) | more than 4 years ago | (#32503564)

Percentages aren't that relevant to this - it's absolute fuel consumption that matters.

If you have a device that saves 1L per 100km, then for every 100km you travel, you will save $1.30 (or whatever fuel happens to be)
This is the same saving whether you're a road train or a vespa scooter.

As a proportion of your fuel bill, it will be less for the road train, but the end saving is the same in either case, and the net reduction in fuel usage is the same as well.

Sure, you don't _have_ to use metric units in the USA, going from MPG to gallons per 100 miles (or something similar) will still have the same benefit in being able to easily gauge relative consumptions of different vehicles, rather than it being an inverse 1/x scale which is relatively hard to judge in your head (compared to a linear scale like volume per distance)

Re:Solution? (1)

ffreeloader (1105115) | more than 4 years ago | (#32503652)

You're still wrong. You're misunderstanding the question. The question isn't which vehicle will use less gas, but which vehicle will use less gas compared to its former usage.

The article wasn't even addressing the question you answered.

Re:Solution? (1)

Strange Quark Star (1157447) | more than 4 years ago | (#32503492)

(dm^3)/(100*km) is fine, but I prefer to simplify by measuring gas consumption in square meters.

Re:Solution? (1)

Monkeedude1212 (1560403) | more than 4 years ago | (#32503536)

Essentially, they wouldn't have to change to metric either, it'd be just as good if you did "Gallons per Mile" instead of "Miles per Gallon".

So I mean, going from 10 Gallon/Mile to 8 Gallon/Mile should save you as much gasoline as going from 6 Gallon/Mile to 4 Gallon/Mile.

Re:Solution? (1)

fishexe (168879) | more than 4 years ago | (#32503610)

Yes, changing the units will most definitely help. The units we should change to are the ones we already use here above the border: liters per 100 km. Going from 20 L/100k to 15 L/100k saves just as much as going from 10 L/100k to 5 L/100k. In most people's lives, the distance you need to travel is constant, not the amount of money you have to spend on fuel, so fuel per distance is much more logical anyway.

Yes, because switching from gallons and miles to liters and kilometers will totally make more sense to people who never use the metric system for anything else in life...

Re:Solution? (1)

Moof123 (1292134) | more than 4 years ago | (#32503314)

However, if we mandated posting the estimated cost of gas over 100,000 the first miles along the lines of how appliances list cost per year for electricity, I think it would help a great deal. Putting mileage in $$$, so that it is in the same units as the car price would help. Quick math can then be done by even the moderately drooling masses as to how many years (or decades) their dream Prius will take to break even with the other options.

Re:Solution? (1)

wiredlogic (135348) | more than 4 years ago | (#32503642)

That isn't possible. Long term consumption is dependent on driving habits, maintenance routine (oil and tires), and the type of gas used. In places where E10 and winter specific gas is used there is less energy capacity per volume than normal straight gasoline.

The question is still absurd... (5, Insightful)

alexandre (53) | more than 4 years ago | (#32503198)

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 ...

Re:The question is still absurd... (1)

adeft (1805910) | more than 4 years ago | (#32503308)

for real. subtract the numbers, which is bigger? thats the correct answer. Percentages have no place in comparing actual performance.

Re:The question is still absurd... (1, Insightful)

welcher (850511) | more than 4 years ago | (#32503310)

The point is that the number of miles driven is assumed fixed. Say you drive 100 miles, then in the first case you could potentially save 10 gallons. In the second case, you can save at most 3 gallons.

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503326)

Insightful ? This poster didn't read the question.

Re:The question is still absurd... (1)

interkin3tic (1469267) | more than 4 years ago | (#32503330)

So 2 out of 3 Americans miss a trick question. Stunning.

Re:The question is still absurd... (1)

molecular (311632) | more than 4 years ago | (#32503390)

that's not a trick question.
it's just that calculating the answer proved to be tricky for 2 out of 3 americans.

Re:The question is still absurd... (2, Informative)

coolsnowmen (695297) | more than 4 years ago | (#32503520)

You're right, not a trick question- a stupid one. why?
because the 50 mpg car is better than all of them. that is the one you buy; that is the one that matters.

Re:The question is still absurd... (4, Informative)

SleazyRidr (1563649) | more than 4 years ago | (#32503346)

There was one comment on TFA which pretty much summed it up for me. Imagine a 2 car family. They have a small car that gets 33mpg for zipping around the city, and a big car that gets 10mpg for more serious work. Would they be better off upgrading the 33mpg car for a 50mpg car, or upgrading the 10mpg car for a 20mpg car. if they upgrade the small car they'll save 1 gallon for every hundred miles it drives, but if they upgrade the big car they'll save 5 gallons for every hundred miles they drive.

Of course the answer depends on how much each of them is used, upgrade price etc. but the fuel usage is an important piece of information.

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503464)

Chances are they're better off waiting until one of their car dies and replacing that. It doesn't usually make economic sense to replace a car just for fuel economy.

Re:The question is still absurd... (1)

chibiace (898665) | more than 4 years ago | (#32503592)

up to a point yes.

Re:The question is still absurd... (3, Insightful)

nosilA (8112) | more than 4 years ago | (#32503350)

Not really. A typical suburban American family has 2 cars - one sedan and one minivan/SUV and may be looking at deciding which one to replace.

Also, it's not the ratio between the gas mileages - it's the inverse that you have to look at. A car that gets 30 mpg uses 333 gallons for 10,000 miles. A car that gets 40 mpg (a "33% improvement) goes 250 miles - a savings of 88 gallons. A SUV that gets 12 mpg uses 833 gallons but one that gets 15 mpg (a mere "25%" improvement) uses 667 - a savings of 166 gallons.

If you are replacing one car this year, is it the civic or the Yukon?

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503370)

This is not insightful. It's wrong.

The question is not about absolutes (where of course a 50mpg car will have better performance per galon) but about margins (where between the options given -- 10 to 20 or 33 to 50 -- the first will indeed save more than the second with respect to the original consumption).

Re:The question is still absurd... (4, Insightful)

betterunixthanunix (980855) | more than 4 years ago | (#32503376)

It really depends on the comparison you are making. If you currently have a 10MPG vehicle, and you have a choice between 20MPG and 50MPG, clearly the 50MPG car is the winner. On the other hand, if you have two families, one driving a 33MPG compact, the other driving an old 10MPG station wagon, and you can choose to encourage the first to buy a 50MPG hybrid or encourage the second to buy a 20MPG SUV, which policy should you pursue?

The point TFA is trying to make is that there are a lot of people out there who need a large vehicle, perhaps because they have a large family, or because they need to transport some sort of equipment around for their work, or whatever. Such vehicles are not going to get 50MPG (at least not with the current state of car manufacturing), but 20MPG is not unreasonable.

Re:The question is still absurd... (3, Informative)

A. B3ttik (1344591) | more than 4 years ago | (#32503388)

You fail, hard. The first scenario goes from 0.1 gallons per mile to 0.05 gallons per mile. You're saving 0.05 gallons of gas with that switch. The second scenario goes from 0.03 gallons per mile to 0.02 gallons per mile... or only 0.01 being save. Making the first switch saves 5x as much gas as the second.

If raw numbers are too hard to understand, imagine going from a two-liter of gas per mile to a coke-can of gas per mile, vs. going from a thimble of gas per mile to half a thimble of gas per mile.

Re:The question is still absurd... (4, Insightful)

Anonymous Coward | more than 4 years ago | (#32503400)

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 ...

I think the point they are making is that a 100 mile trip takes:

10 gallons for a 10 mpg car
5 gallons for a 20 mpg car (saves 5 gallons over the 10 mpg car)
3 gallons for a 33 mpg car
2 gallons for a 50 mpg car. (saves 1 gallon over the 33 mpg car)

    So, creating incentives to get rid of the lowest mpg car saves the most fuel (five times as much).....as opposed to creating incentives to squeeze more mpg out of already efficient cars.

    That is their point. However, in context, if you create incentives to build 20 mpg cars...you actually create a DISINCENTIVE for people to adopt ultra high 33 or 50) mpg cars....effectively reducing the overall fuel savings.

    Changing units will not help Americans understand math...especially when those units are based on 100% gasoline, and not this Ethanol filled crap they sell us at the pump, which DESTROYS gas mileage.

    That, to me, is the biggest "misunderstanding" in the USA today: The addition of Ethanol significantly destroys fuel mileage, destroys engines and components (requiring new parts constructed of Petroleum), AND it makes the gasoline MORE EXPENSIVE THAN IT WOULD BE WITHOUT THE ETHANOL ADDED (once you factor in all the tax money that is given to Ethanol producers...coming right out of our pockets). In short, ETHANOL DOES NOTHING TO REDUCE OUR PETROLEUM CONSUMPTION OR COSTS....it is simply a giveaway to the powerful corn lobby.....

    Also? The use of Ethanol in gasoline drives up the local and worldwide prices for meat (fed with corn), corn, sugar, milk, and a host of other agricultural products that we eat every day.

    If we want to help reduce our Petroleum consumption, step one is to BAN THE USE OF ETHANOL in GASOLINE.

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503442)

RTFA. This is not insightful: it is wrong. It's not about percentages. It's about absolute amounts.

The point is that a bigger percentage increase in the mpg rating causes a bigger increase in absolute consumption.

Have to post AC because I had to mod all these people down. Even /.ers don't get mathematics....uuuuuururghghhghghgh..........they also don't RTFA.

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503452)

The point is to say that in a multiple car family, it is better to try to improve the worst vehicle than to go buy a hybrid or something to replace the one that's already getting relatively good gas mileage.

Let's say you own an older large SUV and a small sedan that gets relatively good gas mileage. Is it better to invest in a small hybrid to replace the sedan or a more efficient SUV/crossover (possibly even a hybrid version of one) to replace the older SUV? The answer isn't straight-forward because you have to consider how many miles you drive each vehicle. If both cars are driven the same distance per week/month/year, then you are often better off improving the worst vehicle. It's a problem of diminishing returns. When you have 10 mpg, 20 mpg saves 50% of the gas. When you have 40, 60 saves 33% the gas. To the person who doesn't understand the numbers though, it looks like it's twice the improvement.

Re:The question is still absurd... (1)

serialband (447336) | more than 4 years ago | (#32503468)

There isn't a 50 mpg SUV yet. While 50 mpg uses less gasoline, drivers won't be replacing their SUVs with a Prius. They'll just buy another SUV. The percent of improvement is more important and will cut down on total fuel usage in a bigger way. It's far easier and quicker to target the low hanging fruit first.

Re:The question is still absurd... (1)

ffreeloader (1105115) | more than 4 years ago | (#32503504)

Uhhh.... No. You misunderstand the question. The question isn't which group of cars uses less gas, but which group of cars reduces its usage the most. That will always be the group with the largest percentage of gain in mileage.

Re:The question is still absurd... (1)

noidentity (188756) | more than 4 years ago | (#32503544)

The question is absurd because it has little practical significance. About the only real situation I can imagine is if you have two vehicles which you drive equal distances every month, and are deciding which to upgrade. One gets 10 MPG, the other 33 MPG, and the replacements you're considering get 20 MPG and 50 MPG, respectively, AND the cost of these replacements is about the same. Very, very contrived.

Re:The question is still absurd... (0)

Anonymous Coward | more than 4 years ago | (#32503568)

I knew a woman who bought a Toyota Prius. She ended up driving twice as many miles as she did before.

Re:The question is still absurd... (1)

zzatz (965857) | more than 4 years ago | (#32503600)

The choices are to replace the first car with the first alternate, or to replace the second car with the second alternate. You're pointing out that replacing the first car with the second alternate saves the most, which is completely obvious. It's also not the question that was asked.

Which has more impact, replacing 1 with 1A, or replacing 2 with 2A? Getting the vehicles with the worst mileage off the road has the biggest impact. Replacing vehicles with good mileage with ones with better mileage is also good, but not as important.

Re:The question is still absurd... (1)

DaveGod (703167) | more than 4 years ago | (#32503644)

The point is we're preaching to the choir. People already concerned about fuel economy are making a big effort for little gains, while at the other end of the scale there is potential for a big payoff from relatively little effort.

The argument is that using a measurement that actually tells people what they think mpg is telling them, you remove a lot of error from the system.

It's a good point. People are told that mpg measures fuel efficiency and they make a natural assumption that mpg is a good measure that works like a good measure should. People know how a measure should work and if they bothered to think about it would correctly complain that mpg is a stupid measure.

Mathturbation (0, Troll)

winkydink (650484) | more than 4 years ago | (#32503200)

What will their next study be? That comparing an apple to an orange is different from comparing a gazelle to a kangaroo?

How about this? Buy the vehicle that gets you the best mileage and still suits your needs.

Oh wait. I didn't piss away somebody's grant money. This can't possibly be right.

Re:Mathturbation (1)

betterunixthanunix (980855) | more than 4 years ago | (#32503508)

I think the point was more about what should be prioritized when it comes to replacing vehicles; you cannot get everyone to replace all of their cars at the same time. So, if you are working on a policy for the US government, what sort of policy should you push? You could give a tax credit to everyone whose vehicle gets more than 40MPG, but what about all of those people who need a large, less fuel efficient vehicle? They won't have any incentive to replace their guzzler, even though it would be a lot better for them to do so.

Re:Mathturbation (1)

Idiomatick (976696) | more than 4 years ago | (#32503542)

If this pushes the states to change units it would convince many thousands of people to look into being more fuel efficient and could result in many millions of dollars saved.

But then America is still trolling the rest of the planet by using imperial so I doubt they'll be switching anytime soon.

as i've always said (0)

Anonymous Coward | more than 4 years ago | (#32503206)

People are stupid !

Breaking! mlpm (5, Insightful)

drDugan (219551) | more than 4 years ago | (#32503212)

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.

Re:Breaking! mlpm (1)

Planesdragon (210349) | more than 4 years ago | (#32503418)

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...

Believe it or not, we have a way to fix that. Change the EPA's guidline to "your cars must get at least X miles-per-gallon" or "your cars must get no more than X gallons-per-mile" Watch how quickly the new number gets onto your local dealers' showroom floors.

Re:Breaking! mlpm (2, Funny)

Mike Buddha (10734) | more than 4 years ago | (#32503522)

WTF's a milliliter?

Re:Breaking! mlpm (1)

taniwha (70410) | more than 4 years ago | (#32503554)

why not use what the rest of the world uses: liters/100km

Re:Breaking! mlpm (1)

Kreigaffe (765218) | more than 4 years ago | (#32503630)

no, the issue is that gallons per 100 miles is a useless number. Well, no, I retract that -- it's a useless number for everything except comparing fuel efficiency between two cars, which, uh, you can do with MPG pretty well. honestly. there's really no use for consumption/distance. nobody has a 10mpg car and a 33mpg car and needs to know if they'll save more going from 10->20mpg or 33->50mpg. That's just a ridiculously contrived scenario from someone who I presume is primarily motivated by their self-induced woes over how unlike Europe it is here in the states. Gigantic eye-roll here.

Seriously. Outside of a math problem for school when would ANYONE ever need to figure any of that out? It's useless information for consumers. So long as there's SOME sort of scale showing its fuel efficiency, you can tell which cars will go further for less. Current car gets mileage X; new car A gets Y, new car B gets Z. That's only 3 vehicles. If X is 10 and Y is 20 and Z is 50, Z will be the greatest increase. Because X always is the same!
And if, somehow, someone IS trying to replace one of two vehicles and needs to know which to replace to save the most money, going by the straight-up percentage increase in efficiency over some distance is NOT going to give you the right answer anyway. USE needs to be taken into account; that is, if you've got a 10mpg car, and a 33mpg car, and the replacement for each respectively would be 20mpg and 50mpg, knowing the percentage increase for replacing either is useless unless both vehicles are driven equal distances. If one is just for hauling heavy loads and the other is the daily use car.. 100% vs 50% increase doesn't matter, you'll get more savings (most likely) by going with the 50% increase as that vehicle will be used much more often (not to mention that 20mpg is going to go down if in fact it is going to be used for hauling or pulling heavy loads -- because most likely that 10mpg your current large vehicle gets is NOT what was on the window when you bought it but rather the actual realized mileage you have been getting with it).

Rant off. This is just another Euro-superiouritist. I just made that shit up. Fact is this guy is creating a contrived scenario that has no bearing on anything in the real world, and while it makes me weep a bit for the critical thinking skills of my countrymen it's just not an issue that ever has any bearing on anything outside of the math skills of the Man on the Spot. I think we all already are aware that if you pose a math problem to random people, most are going to get it wrong. That's not even a uniquely American phenomenon. This guy just needs punched in the teeth I think is what I'm trying to get at here.

Which is why (1)

ShadowRangerRIT (1301549) | more than 4 years ago | (#32503214)

There are always proposals to replace MPG with gallons per hundred miles or something of that sort, since the latter would show the even decline. That said, it's mostly immaterial; the measurement doesn't match naive expectations, but it's still accurate. Increasing MPG means using less gas, and people aren't likely to think about it in terms more detailed than that.

GP100M (4, Insightful)

ceeam (39911) | more than 4 years ago | (#32503222)

I always thought that measuring it Euro-way - in, for example, gallons per 100 miles - would me more practical and clear.

Re:GP100M (2, Insightful)

Anonymous Coward | more than 4 years ago | (#32503272)

As a European, I ask myself: What the fuck is a mile? Is that some UK and/or USA thing?

I think most Europeans would be talking about liters per 10 or 100 km.

Re:GP100M (0, Troll)

ceeam (39911) | more than 4 years ago | (#32503324)

Yes. But since USians cannot grok liters (except, funnily, in engine displacements) and kms I wrote "gallons per 100 miles". It basically comes down to the fact that multiplication is easier than division. And if you know your car needs 7 liters per 100 km and you're gonna take a 400 km trip, 4 * 7 = 28 is easier that dividing 400 by whatever.

Re:GP100M (1)

Sir_Lewk (967686) | more than 4 years ago | (#32503430)

Are you kidding? Americans most certainly know what liters are, and probably see them in every day life more often than gallons. With the strange exception of milk, beverages are most often sold in .75L, 1L, 2L, or sometimes 3L containers.

Re:GP100M (2, Insightful)

tenton (181778) | more than 4 years ago | (#32503590)

Depends on the beverage. Single use beverage containers are more likely to be done in fluid ounces (12oz cans, 20 oz bottles). They do sell soda and water in 1L-3L bottles.

Bottom line, we don't have any consistency and apparently only grok liters for some kinds of drink containers. There's no reference for gas, which is always in gallons here. We're a strange culture.

Re:GP100M (0)

Anonymous Coward | more than 4 years ago | (#32503572)

Yes. But since USians cannot grok liters

Hey fuckface, there are more English speaking Americans than there are britainese and europanoids. Just... just go fucking die before someone kills you over your cleverness.

Re:GP100M (1)

coolsnowmen (695297) | more than 4 years ago | (#32503580)

Km maybe- but liters?!
1 liter = 1 quart (basically). Now everyone gets it.

Re:GP100M (0)

Anonymous Coward | more than 4 years ago | (#32503332)

A lot of the educated people here in the US keep asking the same thing. How the fuck is it possible with global instantaneous communication there are 2 countries left using absurd units when the rest of the world, and the whole scientific community all agree on an international, standardized system of weights and measures. I'm in the US and it is frankly embarrassing.

To the rest of the world, I'm sorry. the rest of the people around me here in the US are zombie religious asshole freaks.
 

Re:GP100M (1)

adbge (1693228) | more than 4 years ago | (#32503366)

A mile is an imperial unit used nearly ubiquitously in the USA. 1 mile is the equivalent of ~1.6 kilometers. For example, speed (in the USA) is typically measured in miles per hour.

I'm a little taken aback that you're not at least roughly familiar with imperial units. I suppose I always assumed that Europeans had a general idea of what a mile is, just as most Americans have a general idea of what a kilometer is, even if they are not entirely comfortable with metric.

Re:GP100M (1)

Mr Z (6791) | more than 4 years ago | (#32503384)

I imagine you'd probably have to go with 1000 miles to get numbers in a usable range:

  1. 10 MPG = 100 gallons per 1000 miles
  2. 20 MPG = 50 gallons per 1000 miles
  3. 33 MPG = 30 gallons per 1000 miles
  4. 50 MPG = 20 gallons per 1000 miles

FWIW, most gas tanks seem to be sized around a 300 - 350 mile range for the expected city fuel economy of the car. So, 1000 miles gives you an idea of the "cost of 3 fill-ups."

2 In 3 Misunderstand Gay Marriage (0)

Anonymous Coward | more than 4 years ago | (#32503228)

I had to do a double take, because that's what I read the first time.

What the fuck... (-1, Troll)

AthleteMusicianNerd (1633805) | more than 4 years ago | (#32503230)

This is idiocracy at it's finest. Go fuck yourself to all the idiots involved in this abomination.

MPG and GPM are both useful (5, Insightful)

JesseL (107722) | more than 4 years ago | (#32503234)

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.

Re:MPG and GPM are both useful (1)

SleazyRidr (1563649) | more than 4 years ago | (#32503394)

It's also useful when evaluating different fuels. I know that in my car, I can put the cheap fuel in and get 25-26 mpg, but if I shell out for the higher octane it goes up to 31-32 mpg. I can easily work out that this is ~23% increase, thus, if the high octane fuel is less than 23% more than the cheap stuff it's worth my while to get the good stuff.

Re:MPG and GPM are both useful (1)

Pharmboy (216950) | more than 4 years ago | (#32503640)

/me smells bullshit. Now how do you get such great mileage using higher octane? High octane gas does NOT have more energy than low octane. 87 and 93 octane fuels have the exact same energy content. (technically, some higher octane fuels have LESS btu potential if they use ethanol to raise the octane.) High octane simply resists detonation better. This means that higher compression engines use it to prevent pre-detonation, and the higher the compression, the most the fuel wants to spontaneously ignite. Higher octane fuel burns slower, not more powerfully. This is a feature.

Pure ethanol has a MUCH higher octane rating, yet will deliver 40% LOWER miles per gallon when used as a fuel, as it contains less energy than generic 87 octane gas.

Re:MPG and GPM are both useful (1)

dwywit (1109409) | more than 4 years ago | (#32503408)

Yep. When travelling long distances - not just the 20-30kms to another town, I mean something like Adelaide to Perth is 2700 kms - you want to know how far your tank of fuel will get you. There are gas stations along the way, sure, but there are also warning signs - "Last gas for 300kms" and the like. It matters less on such a trip that your car will consume x liters per 100km, it matters more when deciding to top up your tank at this stop, or whether your 3/4 tankful will get you to the next stop. Both methods are useful to motorists, for different circumstances.

Re:MPG and GPM are both useful (0)

Anonymous Coward | more than 4 years ago | (#32503436)

True enough. I routinely do a drive on the weekends that would be nearly impossible in some SUVs (it's 225 miles from one gas station to the next - and hot)

Re:MPG and GPM are both useful (1)

orient (535927) | more than 4 years ago | (#32503448)

What's wrong with dividing the tank capacity by the number of liters burned per 100km? My car's 65l tank will last 65/10 (10l/100km in the city) hundreds of km. That is a 650km driving distance or 325 km range.

Re:MPG and GPM are both useful (1)

Relic of the Future (118669) | more than 4 years ago | (#32503570)

Nah, MPG is still pretty useless. If you want to know the maximum range of your vehicle, just have them print the maximum range of your vehicle. I guess MPG might be useful if the rare case that you're the type to stock up on extra gas cans in your truck bed for a long drive, but percentage wise, how many people do that, versus the 66% of people who are screwing up efficiency questions because of MPG being printed instead of GP(100)M?

For the record, I did have to drive 100 miles between gas stations on my Memorial day vacation, and got about 4.6 GP100M (22 MPG) on the trip (it was a relatively rough road, or I might have done better).

Re:MPG and GPM are both useful (1)

NeutronCowboy (896098) | more than 4 years ago | (#32503604)

Why? Because one division is harder than one multiplication? Not to mention, a division involving a two-digit number and (frequently) a one digit number?

Average Schmo's suck at math (1)

Moof123 (1292134) | more than 4 years ago | (#32503248)

News at 11.

An alarming number of folks suck at everyday math, and the worst part is that most don't even realize it. Instead we see them taken in by false sales, and easy to see through misinformation all the time.

I'm not sure if I should call them fools, or try to sell them something?

Re:Average Schmo's suck at math (1)

Mr Z (6791) | more than 4 years ago | (#32503412)

Another fun one to trip people up: A car travels around a 1 mile track. It goes around the its first lap at 30 MPH. How fast does it need to go on its second lap to average 60 MPH?

Re:Average Schmo's suck at math (0)

Anonymous Coward | more than 4 years ago | (#32503494)

Another fun one to trip people up: A car travels around a 1 mile track. It goes around the its first lap at 30 MPH. How fast does it need to go on its second lap to average 60 MPH?

Speed of light, but only relative to an external observer.

Average Schmo's suck at apostrophes (0)

Anonymous Coward | more than 4 years ago | (#32503488)

New's at 11.

question is academic (3, Insightful)

farble1670 (803356) | more than 4 years ago | (#32503266)

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.

2 in 3 cannot do arithmetic (1)

betterunixthanunix (980855) | more than 4 years ago | (#32503276)

My zoned high school (which I thankfully did not attend) boasted a 30-40% "at or above grade level" scoring rate on the statewide basic algebra exam, at least as recently as 2005. This was considered an improvement over the rate from the 90s, which hovered around 25%. I am not at all surprised that so few people can see through a basic ratios problem like the one given in TFA, even though my high school is (hopefully) not representative of the norm.

Re:2 in 3 cannot do arithmetic (1)

orient (535927) | more than 4 years ago | (#32503490)

And what is "grade level"? In North America I found that some university math classes (MATH 2xx and MATH 3xx) are teaching stuff (calculus and algebra) I learned in highschool - Eastern European highschool, that is.

Err..actually its the second one (4, Insightful)

101010_or_0x2A (1001372) | more than 4 years ago | (#32503306)

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.

Actually, no (3, Insightful)

betterunixthanunix (980855) | more than 4 years ago | (#32503438)

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?

Re:Actually, no (0)

Anonymous Coward | more than 4 years ago | (#32503540)

So I could save 10mpg, or I could save 17mpg, gee, what a hard choice!

Re:Err..actually its the second one (1)

molecular (311632) | more than 4 years ago | (#32503556)

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".

Can someone explain how that logic works? I've been trying hard to understand what he means.

It's about perception... (0)

Anonymous Coward | more than 4 years ago | (#32503374)

> But like it or not, lots and lots and lots of Americans need large vehicles for their jobs,

Yes, A lot of Americans overestimate their needs for big vehicle: 2 kids = I need at least a minivan, vacation = only full size SUV can do it, etc...
Same with engine size: 4 cylinders is good for kids and motorcycles. V6 is poor / value seeking only...
Fix the way people perceive the cars - good mileage will follow. We don't need to change consumption measures...

This is science? (0)

Anonymous Coward | more than 4 years ago | (#32503392)

Yeah, because I might be trying to decide if I want to replace my 10MPG F250 with a 20MPG Tacoma or replace my 33MPG Corolla with a 50MPG Prius. More likely, I'll want to buy this car or that car. A car with fuel economy of 20 MPG uses half as much fuel and a car that gets 10MPG. That's good enough for way more than 2 out of 3 people.

If you really want to get scientific, we need an article proclaiming, "People just don't understand brake specific fuel consumption."

Regards,
Jason

Re:This is science? (1)

tthomas48 (180798) | more than 4 years ago | (#32503534)

But most people do consider cars in the same class with similar mpg ranges. So more likely you would be considering a 21mpg vs. 19mpg or 30mpg vs. 28mpg. Since there's a big difference between 21 and 19 and not so much between 30 and 28 (even though the difference APPEARS to be 2), I think having customers understand this IS huge.

American's suck at math... can't invert... (0, Troll)

jeremyhu (164852) | more than 4 years ago | (#32503420)

This article has really one main point. American's are bad at math. They can't even invert a number that is in "miles / gallon" to figure out "gallons / mile" ... which I think is true... most Americans would fail 6th grade math.

Re:American's suck at math... can't invert... (1)

starfishsystems (834319) | more than 4 years ago | (#32503546)

They're also kinda bad at pluralization.

Americans are dumb (1)

Singularity42 (1658297) | more than 4 years ago | (#32503454)

Except the Americans who post here.

Problem isn't the units (1)

by (1706743) (1706744) | more than 4 years ago | (#32503458)

Or Americans, since any (Real) American should be able to tell you that a 12-gauge shotgun is bigger than a 20-gauge shotgun. Point being, we use units which are inverse of intuitive, and don't seem to have a problem with them.

I say this as an American who thinks the gauge system is weird, the mileage system only slightly less weird, and guns rather silly...

It saddens me (1)

hallucinogen (1263152) | more than 4 years ago | (#32503516)

That people are this stupid in such great numbers. FFS I could have done the math (and I assume all my classmates as well) back in 2nd or 3rd grade. How do these idiots manage to survive?

Saves? (0)

Anonymous Coward | more than 4 years ago | (#32503518)

>>Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg?

Neither saves gasoline... both SPEND gasoline. The question should be "Which spends less gasoline?" since neither of the previously mentioned options saves any. Saving would imply a comparison of a reducion against a previously established value.

Here’s the math (1)

starfishsystems (834319) | more than 4 years ago | (#32503524)

The article says "here's the math" and then proceeds to offer an example involving not math but arithmetic.

Whether the fuel consumption ratio is expressed in distance per volume or its inverse is not as important as the simple recognition that it's a ratio. But when people blithely speak in terms such as "five times less" there is bound to be a fundamental confusion between ratios and differences.

Simple solution (1)

u19925 (613350) | more than 4 years ago | (#32503526)

Change mpg to gpm.

MBA math (1)

oldhack (1037484) | more than 4 years ago | (#32503558)

How does the difference between a factor of two vs. a factor of 1.5 translate into "5 times"? Some kind of crazy "MBA math"? ;-)

Hmm... (1)

BauerUK (1387393) | more than 4 years ago | (#32503586)

...maybe a computer science analogy is what's needed to fully understand the concept?

Litres/100 KM (1)

Denis Lemire (27713) | more than 4 years ago | (#32503594)

This is why I prefer the Litres per 100 KM. It solves the problem this article describes.

Plus 'Gallon' is ambiguous.

ie) In Canada car ads often use imperial galons, but you may also see an American ad that uses US gallons. You have no way of knowing which the ad intended.

There is only one definition of Litre.

10-53 (1)

snowboardin159 (1744212) | more than 4 years ago | (#32503612)

Yes, but if u replaced ur 10mpg gashog with a 53 mpg car, youd save even more...
Just a thought.

The rest of the world uses L/100km (1)

thisisauniqueid (825395) | more than 4 years ago | (#32503616)

end of message

best unit: $/year (1)

molecular (311632) | more than 4 years ago | (#32503624)

$/year is best unit, everyone understands that.
unfortunately that's not constant across users.

So there's the math problem... (1)

Snarkalicious (1589343) | more than 4 years ago | (#32503638)

...but is there really an issue with being drawn to the higher number (50, as opposed to 20) as long as the terms remain the same and the outcome is reduced consumption?

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