'Miles per gallon' can misrepresent a car's fuel efficiency

[itchykami]

so wait, this is just a video on semantics.

[Jinmane]

This is so damn obvious. If I had a car that did 100mpg, then I would not consider upgrading to a car that does 150mpg as 100mpg is so efficient already that it would be not worth upgrading much further, whereas upgrading from 10mpg to 15mpg is clearly a bigger save on fuel.

[johnbell58]

What a silly video, it made no good point except to tell us that people cannot do math, and they are customers, not consumers. Needs a better point and a better producer.

[trogdorfiend]

good point. i thought that upon watching this video, i would have a better grasp on the fuel economy gauge. this is not the case, however, as i have learned nothing from this video which features DUKE scholars (where's all that money going, anyways?)

NewScientist must be catered to the lower masses

[indigoyuggy]

In portugal we measure consumption on Liters per 100 Kms, an efficient car will drink up 4,5 down to 3 Liters per 100Kms

[nanophreak]

What they're saying is people look at the mph as how much they're saving, but you really have to calculate, or the company should calculate, how many gallons of gas you need to travel a certian distance, because that's where you're spening.

[drizztman101]

True, but not everyone drives a 10 mpg car

[CAbbott71]

If this is news then the education system in the USA is pathetic.

If I have a 10MPG truck and I compare it to a 20MPG truck, guess what, the new truck can go twice the distance on a full tank of gas, or use half the gas travelling the same distance.

This is primary school maths!

NB: When travelling outback, it can be 500 miles or more between fuel stops. MPG x Fuel Tank size = distance you can travel before refuelling, a value you need to be wary of. In this case, MPG is the easier rating.

[SirTragain]

They stated two situations.

First if you got 10 MPG up hill for 100 miles and 100 MPG going down hill for 100 miles you would have averaged (100/10=10) + (100/100=1) 11 MPG over the 200 mile trip burning 18.1818 gallons of gas at either $3.999 or $4.009 per gallon so it would have cost $72.71 or $72.89 US Dollars to replace that gas.

Second how much does the replacement car cost including any insurance difference verses any possible savings?

[SirTragain]

10k miles a year at 20 MPG is 500 gal vs. 50 MPG is 200 gallons a 300 gallon savings at $4.009/gal. is $1,202.70 differance over 5yrs. would be $6,013.50 so subtract that from the price tag of a hybridand then just compair the cars prices.

[PetrFM]

We use litres per 100 kilometers in Europe witch is perfectly linear -just another reason why to leave outdated imperial unit system.

[thesenamesaretaken]

Surely the point made here is nothing to do with Imperial vs. Metric (Yay Imperial!)

The point raised is that it's better to rate fuel economy as 'volume of fuel per unit distance' rather than as 'distance per unit volume of fuel'.

I used to think it didn't really matter but I suppose there is more clear to use such a measurement.

[BlkRider]

The point made by PetrFM is that in Europe we use this "ground breaking" discovery for about hundred years...

[thesenamesaretaken]

"just another reason why to leave outdated imperial unit system"

Doesn't seem that way to me. Seems more like someone has a problem with our way of defining lengths and volumes.

Also I don't know what was up with my last sentence up there. Maybe I was in a hurry?

[freewee21]

@BlkRider what do you mean "we".you as "we"or the people who really found it out. now you see how people take others credit just because they live in the same nation.in other words just because theres alot of smart people around you doesn't mean go on youtube later and say "im smart".one more just beacuse you're British for instance doesn't mean you can go on youtube and say "hey i'm british we made bmw,im so great we made bmw".points is stop taking other credit.ur just using there formula

[BlkRider]

@freewee21 You should read more carefully. I said we USE the metric system. And by we I mean everybody in continental Europe as far as I know. And BMW is German not British ;).

[RealMash]

Sorry to be upfront etc. but it is presented as litres/100km in Germany( I know ), France(I read in a French car magazine) and probably the rest of Europe. I was dumbfounded the first time I heard the American way to do it.

It is done the way they describe in Europe at least for fifty years!

And you need New Scientists to figure that out? What Europe does (metric, of course) for the last decades?

Dumbfounded again,

Michael

[Zoiros85]

In Norway we use:

liters/mil = liters/10km

[vchasinatorv]

i don't want to fight... lets just make love

[vchasinatorv]

how do you figure?! the ratio is a direct indicator... ie: 1 mpg vs 2 mpg/ 2 mpg vs 3 mpg

[vchasinatorv]

Ok, hear me out. In straight forward blunt math, yes, the difference is obvious, you save more. That is why I said earlier that you have to look at the RATIO. How do you not understand it?! I am baffled by your lack of intellect.

[vchasinatorv]

Of course not. and if you think it would than you need to take a hammer and hit yourself in the head with it.

[vchasinatorv]

Now, mr ingorant thelleht.... I realize that you are quite unintelligent, so i will break it down for you... when going over a set distance for both sets of vehicles, the difference will be obvious that the lower mpg cars will have a larger difference in gas used, but you have to look at the ratio.. your parents must hate you

[vchasinatorv]

and before you jump all over my spelling error, it is obvious that i meant ignorant.

[vchasinatorv]

yes.. 10 mpg would take 100 gallons... 15 would take 66.7 gallons, 25 would take 40 gallons, 50 would take 20 gallons..... now genious, I understand that 33.3 is a larger difference than 20, but that is only because you need more gas over all... if you went far enough for the 25 mpg car to expell 100 gallons than the 50 mpg car would use 50 gallons... you are a moron

[vchasinatorv]

Wow thelleht.... You are retarded...... seriously..... Let me put this into moron easy to understand terms for you... 15 mpg is 1.5 times better than 10 mpg... while 50 mpg is 2 times better than 25 mpg... a fucking 5 year old child could tell you that 2 is a larger number than 1.5.... and irregardless of me just winning that argument, its not about how its better to replace a 10 mpg with a 15 mpg than a 25 with a 50 (because its not) its about how even smaller changes can still add up over time

[RyuDarragh]

Poundage (payload) *should* be part of the picture. My 2000 Toyota Carolla gets 34mpg (rated) and yet, while driving my 250lb frame over highway distances, I get 44mpg. MPG is affected by payload so comparing the MPG of a truck, designed and *intended* to get best milage when *loaded*, to a car is about like comparing a carvac to a shopvac.

[RyuDarragh]

The real problem is the flawed anology used in the video. How *much* better usage of gas is a slightly better passanger car compared to a much better truck ? Not very simply because a *truck* is never going to be as efficient as a passenger carrying vehicle as a car designed to *be* a passanger carrying vehicle. What the video was talking about was *relative* improvments and, I am sorry, the car wins even if it got only 2 more miles per gallon than the truck.

[RyuDarragh]

Don't forget, the truck can be twice the metals and plastics of the car and has a greater impact on the road surface, etc.. even if the *cost* to the consumer for the better truck were about on a par with the car, it's better for *everyone* if consumers stopped using 5lb sledgehammers to drive finishing nails and went and got cars for playing taxi for the kids and shopping instead of SUVs.

[RyuDarragh]

When that vehicle that can get 50mpg can only carry 1000lbs of payload and the one that gets 25mpg can carry 5000lbs of payload. What you need is "Miles Per Gallon Per Pound of Payload" to get any meaningful number from that. A moped can get 100mpg.. let's see you take the neighborhood of kids to school on it.

[DaviesFamily213]

Isn't it already obvious

DUH?!

which morone can't tell that a vehicle that does 50MPG is more economical than a vehicle which does 25MPG.

[Marth48]

Ummm... How is telling you how many gallons of gas you use in 1,000 miles, any different from telling how many miles you get in 1 gallon? And instead of improving SUVs and Hummers, why not STOP MAKING THEM.

[thegorilla69]

old arguement....Honda's clarity. water is more powerful than gas.

[Spanky2k]

Errr.... MPG = GPM^-1. Is anyone really as stupid as these researchers claim??

[RyuDarragh]

Parnellcakes, escalade220's English is vastly superior to your Croation, I'd bet. Who has a better education.. the man who can get along passably in English and speaks Croation or the man who only speaks English ?

[RyuDarragh]

Better is to stick with a single standard. Total gallons per 100 miles. Thus, although you may have a greater efficiency jump from 10 to 20 MPG on an SUV compared to a compact going from 25 to 50 MPG, it still sucks a hell of a lot more gas than either of the compacts to go the same difference. This still does not address payload versus efficiency. A truck that can carry 5,000LBS payload at 10MPG is more efficient than one that can carry 1,000LBS at 25MPG over the same distance.

[Nephallux]

that is what should be noted by them, which was left out. it's the same as "going uphill" as they put it.. using more gas to go the same distance...

[ebscer]

GPM is just 1/MPG both are giving the exact same information. The only difference is the formatting...

[BODenKai]

thats why its called Average MPG not MPG Averages duhhhhhhhhh

[joeyismyname221]

truly truly amazing

[ReisendeEuropa]

I'm curious why late model cars aren't more efficient. My 1984 Toyota Celica with a 150hp, 2.4L engine got 22/26 or 24mpg average driving in east Tennessee. One of the only late cars I could find with a similar engine is the 2008 PT Cruiser. It has a stickered mpg of 18/24 but people actually driving it have reported 15/19 or 16mpg/avg. My 1996 Jeep Cherokee was better than this. With a 4 litre engine it got 19/25 or 22mpg/avg. The weight of these vehicles differs by only a few hundred pounds.

[escalade220]

these are scientists?? we in eurpe use measure litres per 100 kilometres long time ago... you laisy people

[Parnellcakes]

You can't even spell Europe?

[hodor]

Errrrr,

dump the 10 mpg truck for the 50 mpg car, save 8 gallons!!!

Is this where I am suppose to point and shout out "MORONS!"?

[TheReasonWhyGuy]

CHANGE IT!

[darwinmommy]

BADLY WORDED QUESTION:

"Which is better to replace?" -- the ambiguity in the wording of the QUESTION makes for the confusion, NOT the choice of measurement units. One immediately feels confused: "better in what sense"? Do you mean, "better for the environment?" Most people aren't thinking about that when you ask it. Most people are thinking about how many more miles they'll get for each gallon paid for. And for that, they ARE giving the correct answer. SOMETIMES THE PROFESSORS GET THE "F"

[squidmanlol]

these videos are always fascinating

[redbeast2]

This is why everyone outside of the USA uses volume per distance fuel efficiency figures, not distance per volume.

[samgee2007]

america is backward country!if tell them litre thay probably wont understand!they are idiots

[ncponder]

And if it weren't for those idiots, you, you super intellegent being would not be able to make this public statement....

[psarmstr]

This is why most countries use L/100km and we should too. We'd gain a whole lot of advantage by changing to this way of expressing efficiency. Some basics to get you started (using current EPA estimates): - Prius: 5.1L/100km - Acura TSX: 9.4L/100km - Audi TT: 9.8L/100km - Subaru Legacy, BMW Z4: 10.7L/100km - Chevrolet Colorado: 11.7L/100km - Toyota Tacoma: 13L/100km - F150: 15.7L/100km - Ford Expedition: 16.8L/100km

[marky1333]

Thats a good point, but the reality is when brits switched to buying fuel in litres everyone lost there reference point, no one understood how much they were paying anymore. So from an awareness of fuel efficiency point of view, it was really damaging. Brits still use MPG as a reference point even after 15 years of buying fuel in litres or they talk about how far there car will go on 20 quid.

[marky1333]

It also allowed the government to dramatically increase the tax on fuel because £1.20 a litre sounds a whole lot cheaper than £5.47 a gallon.

[psarmstr]

That has _nothing_ to do with it. They made a policy decision to increase tax to a) bring in more money and b) discourage the use of private vehicles because there's a fairly significant public transit system.

There was as much outrage when gas crossed the Dollar/Pound/Euro 1.0/L mark as there was here when it crossed $4/gallon. Completely unrelated to tax.

[marky1333]

It did allow them to increase tax(by stealth) when they first switched to litres and people did'nt realise how much they where paying . I know this because i remember it well.

How can a product thats value is 70% tax be completely unrelated to tax

[psarmstr]

Gas prices go up. They were going up before the change and after the change. If your politicians dishonestly aligned a tax hike at the same time, then they were probably doing a lot worse things without you noticing.

One of the reasons for doing this is that you seem to have converted the price per liter to UK gallons. The sentence you just wrote looks bizarre from a US stand point as the size with the same name (gallon) is a different measure (4.55L for a UK gallon vs 3.79L for a US gallon).

[marky1333]

miles per gallon are deceptive for U.S consumers because there are only 6 pints in a U.S gallon where as an imperial gallon (i.e the rest of the world) has 8 pints. American cars are more fuel efficient than is made out.

and

Americans are paying a lot more for gas than they realise!!

[psarmstr]

The rest of the world uses metric. Even the Brits buy gas in liters.

[redbeast2]

huh?

[DiabloDeLuna]

Double check your info, marky1333. A pint is 1/8 of a gallon, imperial or not.

[DiabloDeLuna]

By the way, this kind of confusion is exactly why the US needs to get off its ass and switch to metric.

[marky1333]

Im pretty sure consumers will totally 'get' the finer points of fuel efficiency when it goes to $20 a gallon and i say WHEN not IF!

[joey007007]

u wud hav to b an idiot, for this to actually come as a shock, or for it to convey anything new

[ripperdream]

screw metric!usa#1 we will burn ALL the gas on this planet,and you piss ants can kiss our big fat asses!

[marky1333]

Is that ALL the gas comin out of your big fat asses

[calvinjones]

smart.

[iynque]

I heard about this on NPR. Very cool. I still don't get the difference between MPG and GPM...

[dbohls]

Did you hate math growing up?

[DiabloDeLuna]

LOL. MPG = 1 / GPM. Advice for iynque: don't do your own taxes.

[UsernameDJ]

this is why you use letters per 100 km.

[IgWannA2]

that's pretty cool.

[blakevancouver]

So happy to see the north americans waking up to the metric system. Doesn't anyone know that the rest of the world measures consumption in liters per 100 kilometers???????And that this makes it so simple to price your individual consumption. Plus they go on about gallons, like, as if that's clear, eh? Heard of Imperial measures, boys? Want to get people to think about this in the right way? USE METRIC!

[dbohls]

It'll be another 50 years because we make the switch to metric. We're too busy worrying about what our citizens are doing in their bedrooms and about concocted lies like epidemic youth violence.

[XxTrailofDeadxX]

This video is completely retarded. You're saving only 2 gallons per 100 miles, but you're saving that every 100 miles. Of course its always better to go with the most fuel efficient vehicle - all things considered equal. This video is a complete waste of brain power.

[JaMoond]

Of course if all things considered equal. However, it's asking how much improvement you get from changing your car. You completely forgot that hybrids costs a lot more than regular vehicles, and you have to consider if I'm going to change to hybrid, will I get significant improvement over my previous vehicle?

[CactosS]

yeah i didnt finish high school iwas aware the more efficiency less gas is spend, and didnt need go to college to now this,anyone can know the drive a wheelbarrel with four cylinde is cheaper than a 5.7 litter hemi engine

but american like big and powerful vehicles

[dbohls]

Yes Cactos, and I didn't need you to tell me that you didn't finish high school to know that. You might be smart, but it doesn't come across when you write like that.

[oggleman]

Bravo!

[Agentkalaw]

Another factor that they didn't touch upon is the "miles per gallon per individual".

An airplane uses so much gas to travel coast to coast but if you break down the amount of gas used per person that it transports and comparing that to any car (even hybrid) going coast to coast, you actually get less fuel used. Another example is one suburban carrying 8 people and gear gets better fuel efficiency than two priuses with 4 people in each car and same amount of gear.

[silver0123456]

80% of the time those suburbans carry one person...

[Agentkalaw]

True, I'm just saying...

[thanatos454]

This seems so obvious to me that I think this video is just pointless. *shrugs* :\

[Soufpaw]

only 1/3 of humans achieve formative thought (i.e. making non linear associations, ability to thing abstractly). So there are two other people who found this video useful while you were commenting. Now I have to find the other two people who did'nt understand my point.

[ELUzairo]

i get you.. now lets find the two ppl who dont understand how i get you!

[javierenchina]

this video didn't actually tell us anything new, they're just academic people who need to say something novell to justify the fact that all the do in life is talk. more mpg means more fuel efficient. kthx

[raffadizzle]

that was crazy and informative! i'm going to make sure to share it with my friends :)

[MrBloody32]

I agree, soulhunger, this video should be featured. Especially since YouTube tends to have an audience of young college students who are often strapped for cash.

[tetranoob]

I had to watch this twice to understand.

[soulhunger1]

This video should be featured.

[cetuscript]

liters/100km (or at least volume per distance) is the right way of looking at fuel consumption.

But it is aggravating to marketing people and confusing to regular folk. We want better to be expressed as a bigger number. L/100km means that better gets smaller. 7L/100km is better than 10L/100km but 7 is less than 10 ---> confused general public.

That's why, even in Canada, you will still see MPG shown when advertising vehicles. "Bigger is better"

[ificouldtalkiwould]

seems like they really didn't prove anything tome, i guess i just don't understand.

[PoliomanGamer]

Why is the US the only country to use the english metric system? even England is not using it anymore.

[scruffyartstudent]

I think you mean imperial. Good question though: probably a combination of factors. Geographical distance from Europe being one, level of autonomy being another.

[kurthurtig]

stubborness id suppose

[SobaniForce]

Well over in australia we use Litres/100km, which is much easier to rate different cars, and helps you calculate your range easier.

[kurthurtig]

Well... I dont see their point. If youd exchange a 10mpg car by a 25 mpg car you won even more. if you buy instead a 40 mpg car (like the prius) you saved even more gas... so i think the mpg is a good indicator.

[JasonMelancon]

The point is that linearity in the relation between the savings and the efficiency index (be it mpg, or liters per 100 km, or whatever) is less confusing.

The difference between two cars in gallons per mile is an *actual savings* that you can take to the bank, for every mile that you drive. On the other hand, the difference between two cars in mpg is nothing meaningful at all. If you trade in your hummer at 5 mpg for a hybrid at 40, do you save 35 miles? What does that even mean?

[kurthurtig]

no, you gain 35 miles per gallon.

i dont think the difference btw old and new car should be looked at, but rather the absolute value of the car.

just because you were driving a hummer and now switched to ford mondeo, does not make you a environmentaly friendly person.

doing better than before is not enough. do your best!

[stevensteven327]

that was actually pretty interesting

[cetuscript]

How about liters per 100 km? ;)

[kurthurtig]

a gallon in britain is 3,8 ltr in the states it is 4.5 ltr. a mile is 1,6 km. so taking the value of mpg as x you can solve: 1/(x*1,6/3,8 or 4,5*100)

that gives you roughly 6 (US) or 7 (UK) for 40mpg.

[noodlemasta]

@Cetuscript: Exactly as I was going to suggest!

[kurthurtig]

thank you.

by thew ay.... im fucking wasted

[RoySchl]

Germany has liters/100km

[tetranoob]

Viva Germany! i've heard good things about your roads

[JasonMelancon]

That's cool, but 100 km? Why wouldn't you use 1000 km? That way you can call it a "megameter", Mm. LpMm, or LpM. Much smaller mouthful.

[rhoula]

great video.

Thank you for sharing