2 In 3 Misunderstand Gas Mileage; Here's Why 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."
3 people in 2 don't know math. (Score:5, Funny)
News at 11!
Re:3 people in 2 don't know math. (Score:4, Interesting)
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: (Score:3, Insightful)
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.
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.
Re: (Score:3, Informative)
That particular asylum is run by the inmates (That is, Energy Star ratings are paid for by the manufacturers and there is little oversight).
Re:3 people in 2 don't know math. (Score:5, Informative)
They tell you not just the MPG, but
it even has calculators so you can plug in your own average miles traveled and driving style and determine how that effects the above.
also on there has a "garage" feature where you can have your cars and plug in how much you paid for gas and how many miles you got per gallon. (you don't even have to do the math yourself) and it will plot your mileage and allow you to compare what you're getting against the car's listed ratings as well as other drivers with the same car as you. I've got complete gas mileage charts for ever car I've owned over the last few years thanks to that site.
The site was created by the American government, it's been around for years, and it's openly available to any American smart enough to conjure the phrase "Fuel Economy" and plug it into Google.
Not everything needs to be stickered to the damn car... 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. Don't assume that the only information available is only what's fed to you in TV ads...
I have used this site to track my last two cars (Score:5, Informative)
and will be using it to track my latest.
The first car I tracked was a 2007 Civic Coupe EX, manual transmission. The second was a 2008 Mazda Miata SE. Without bouncing to the site to check the Miata was rated at 21c and 28h. In my two years of recorded mileage I never fell below 27 in a mix of city and highway travel; I have a 26 mile commute mixed between 35 and 55 with no interstate. I peaked at 33 during summer months and fell into the 27 range during winter where besides the cold requiring the engine to run rich I needed the compressor to run the defroster.
My newest addition, a 2010 VW Golf TDI with manual transmission shows that others have never been as low as the EPA predicted mileage which is 30c and 41/42h. I have yet to finish my first tank and the car's computer shows 38 miles per gallon.
Why all the fuss? Well the facility is there and it gives me a nice reference to see how my car reacts to seasons and how it reacts to age to include over all miles traveled. It provides a nice little log so I can also see fluctuations in fuel prices without having to rely just on my memory; like what was the price of gas in June 2008.
While many cars are not represented it does appear those with cars known to get good mileage do post their numbers more often. I have been surprised while browsing some vehicles to see just how low the mileage ratings are for many popular sedans, in many cases not better than many SUV/CUV types that people love to vilify.
Re: (Score:3)
Re: (Score:3, Insightful)
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.
Re: (Score:3, Funny)
Jesus christ, if you have a brain in your skull you know that you're not going to get people to google the car's fuel efficiency. A consumption-based sticker, right on the car, that people don't have have to work to see, will actually work. Don't worry, you'll still be able to be a smug cocksucker even with the sticker there.
Re: (Score:3, Interesting)
Their numbers are under controlled circumstances. They vary by driver, conditions, and modifications.
My car, a 2000 Pontiac Firebird TransAm WS/6 with a 6 speed manual, is rated for 16/25.
In my own long term testing, I get 25mpg at 55mph, which increases to 26mpg at 65mph, 27mpg at 75mph, and 28mpg at 90mph. I've never felt comfortable doing long term tests over 90mph. :) All of the highway speeds are the normal cruising speed during the test. It does not inc
Fly? more like crash.. crash and burn (Score:3, Informative)
it certainly does not fly
http://www.popularmechanics.com/home/improvement/energy-efficient/4350335 [popularmechanics.com]
In the rest of the world (Score:5, Informative)
10 miles per US gallon = 23.52 L/100km (mind-bogglingly bad)
20 miles per US gallon = 11.76 L/100km (very bad)
33 miles per US gallon = 7.13 L/100km (OK for SUV, not so good for a car)
50 miles per US gallon = 4.7 L/100km (good for medium or large car, not so good for compact car)
FWIW, my Mercedes diesel stationwagon uses about 5.5 L/100km for mixed city/rural driving, which is 42.8 mpg(US) or 51.4 mpg(UK).
Re: (Score:3, Informative)
10+ liters per 100 km is about on par for a 10-15 years old european sedan in busy city traffic. For the same car, 6-7 liters per 100km is typical at 90-100 km/h.
Newer cars do better (but city traffic still takes a toll, as it is very dependent on car mass).
Re: (Score:3, Informative)
Most of the US is laid out in a fairly rigid grid system. We have mile markers (and still use miles) because that's how far apart intersections are. Going to metric would be stupid, making many things complicated. Most people would have to then convert to standard units.
No, using L/km is stupid, since they're not units anyone is familiar with, and gas is pumped by the gallon. Unless we're going to change the entire infrastructure - and you thought the E85 or "over $4/gal" was costly to fuel distribution - t
Re: (Score:3, Insightful)
Why is the US so stubborn about adopting the International System of Units [wikipedia.org]? Even the country where the "Imperial" units come from did. And while we are at it, why not adopt iso 216 [wikipedia.org] and be done with silly sheet sizes?
Re: (Score:3, Interesting)
"Why is the US so stubborn about adopting the International System of Units? Even the country where the "Imperial" units come from did."
That's a very good question. Does this Metrication Matters guy have any answers? If we want to metrify the US, a good first step would be to figure out why we haven't already, and not just bitch and moan about Americans being stubborn. The only other countries that haven't switched to metric are Burma and Liberia, but maybe we could compare America with countries that were
Re: (Score:3, Insightful)
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 met
Re: (Score:3, Informative)
> and had no need to remember the conversion when they learned it in science class.
That's because they teach a crappy remembrance system...
Compare and contrast to the SIMPLE way that you can do in your head:
miles -> km: x*2*2*2*2/10
i.e. 60 miles = 60*2*2*2*2/10 = 120*2*2*2/10 = 240*2*2/10 = 480*2/10 = 960/10 = 96 km
km -> miles: x/50 + x/10
i.e. 100 km = 100/2 + 100/10 = 50+10 = 60 miles
--
Why Math just isn't taught properly anymore.. A Mathematician's Lament [maa.org]
EnergyStar is a joke (Score:3, Interesting)
The depth of a joke that EnergyStar is was put in stark relief when the GAO (through a fake company set up for this very purpose) managed to get an EnergyStar label for a gasoline-powered alarm clock [engadget.com].
typical US government stuff really (Score:4, Interesting)
I had to cringe when you said "is underfunded and overstretched". Really this sort of organization shouldn't require any funding, and should simply use trademark rights to assert licensing terms with partners (manufactures, building contractors, etc). EnergyStar *almost* operates that way right now, given that it is a voluntary program.
UL(Underwriters Laboratories) is a private entity that required certain specific safety testing to be passed by a product before the UL logo can be placed on that product. They have a fairly narrow scope though, mainly for fire safety. But it is one of only a few testing labs recognized by various local building codes in the US as well as federal organizations such as OSHA. Testing fees are modest, and the organization is able to scale with demand.
Another example with is Snell. To use their logo on your helmet requires specific tests, the tests are fairly expensive so not all helmets are Snell certified, but part of their budget funds helmet safety research.
Why EnergyStar can't operated the same way, I do not understand. It seems like if we had an international standard (one of the positive aspects of EnergyStar) that provided oversight and certification of various testing facilities to authorize them to grant limited rights to licensed partners to claim certification would be scalable and efficient.
With an obscure government entity there are almost always problems with oversight and responsibility. When EnergyStar gets in trouble there is no CEO or politician to blame, it's all just faceless bureaucrats. In situations like these it is the media's responsibility to expose failures in a bureaucracy, but the side effect is consumer trust in the EnergyStar brand is damaged. A business operates differently when trust in a brand is important.
Re:3 people in 2 don't know math. (Score:4, Informative)
See... in Canada, most large appliances have exactly that measurement plastered on a sticker on the door. kWh/year estimated. And for the most part, these are the same brand names (and probably the same appliances) you can find in Europe and the US... brands like LG, Whirlpool, and Maytag.
So the testing is already done. And admittedly, it's very difficult to accurately measure the overall usage for an electric stove (one of the main reasons I use a gas stove, though they're generally more efficient anyway, as they take less time to heat up/cool off, so less energy wasted), but for something like a fridge or an air conditioner, it's a better measure. I think they even have a "standard" duty cycle that they include in the measurement specifically because something like an electric stove or microwave won't be on 24/7.
And on topic, we already use L/100km for measuring cars' efficiency, too. You'll find it right next to the old MPG measurement for people who are used to that. 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.
Re:3 people in 2 don't know math. (Score:4, Insightful)
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...
Re: (Score:3, Funny)
Re:3 people in 2 don't know math. (Score:5, Funny)
Duh, after I have had seven fifths I have trouble with math as well.
Re:3 people in 2 don't know math. (Score:5, Funny)
> 3 people in 2 don't know math
Wow that's scary. That's nearly half!
What we need (Score:4, Funny)
Clearly, what we need here is a car analogy!
Anyone?
Cheers,
Re:3 people in 2 don't know math. (Score:5, Funny)
> 3 people in 2 don't know math
Wow that's scary. That's nearly half!
Seriously? Are you really that stupid? 3 divided by 2 is 1.5, which isn't even close to 50. What the hell do they teach kids in school these days?
Re: (Score:3, Interesting)
3 / 2
= 3 * 0.00067 cents / 2 * 0.00067 cents
= 0.002 cents / 0.00133 cents
= 0.002 dollars / 0.00133 cents
= 150
Gee, that wasn't hard, was it?
Re:3 people in 2 don't know math. (Score:4, Funny)
Go away. Verizon employees aren't allowed to post on Slashdot.
Re: (Score:3, Funny)
Yeah, I know it sounds ironic but math errors happen when you get outraged at the lack of basic math skills in America and try to do division.
Re:3 people in 2 don't know math. (Score:4, Interesting)
I never really managed to wrap my mind around the concept of MPG either. Yes, I'm European.
I wonder why it's defined that way in the US. It sure sounds more positive. I mean, you "get" a certain amount of miles out of a gallon of gas instead of "needing" a certain amount of gas to go 100km. Still I think it's easier to compare lp100km rather than mpg. It's trivial to calculate how much a kilometer costs me. Not so with mpg.
Re:3 people in 2 don't know math. (Score:4, Informative)
> Still I think it's easier to compare lp100km rather than mpg. It's trivial to calculate how much a kilometer costs me. Not so with mpg.
You're kidding, right? It's a simple reciprocal.
20 MPG = 1/20 GPM = 5 gallons/100 miles.
It doesn't matter whether it's gallons/liters or miles/km, the relationship is equivalent. That's why this article is red herring.
Re:3 people in 2 don't know math. (Score:4, Informative)
I mean, you "get" a certain amount of miles out of a gallon of gas instead of "needing" a certain amount of gas to go 100km.
America's a pretty large country and we tend to take a lot of long-distance road trips. When I used to visit the in-laws, we'd pile into the family minivan and drive 1,100 miles each way to get there. As others have said, MPG is good for calculating range. If I filled up with gas in Chicago, should I get more gas in Cleveland just to be "safe", or can I wait until I'm in Pennsylvania?
Still I think it's easier to compare lp100km rather than mpg. It's trivial to calculate how much a kilometer costs me.
For my family, the cost of fuel is unimportant. For daily driving, it adds up slowly enough that other expenses like maintenance and insurance are more important considerations. For long trips, the cost can be significant, but not enough to deter the trip even if we had to pay twice as much. Now, fuel economy will still factor into my next purchase, but once I own the vehicle, it's just not something that I care to think about. I already have the thing and I'll pay to put gas into it whenever I need to. Once I've done that, I'm more interested in how far I can go until I have to do it again.
Re:3 people in 2 don't know math. (Score:5, Funny)
Re:3 people in 2 don't know math. (Score:4, Funny)
Solution? (Score:2, Insightful)
I don't know if changing the units will help much ..
Re:Solution? (Score:5, Informative)
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? (Score:5, Insightful)
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? (Score:5, Funny)
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? (Score:5, Interesting)
So let's use English units (even though England doesn't even use them anymore!)
There are 128 fluid ounces (oz) in a gallon. So oz/mile (let's call it OPM) is equivalent to gallons/128 miles.
This also happens to be about half the European value. (5 L/100km == 2.72 OPM == 47 MPG)
Re:Solution? (Score:4, Insightful)
..ahhh England where I buy fuel in litres, put it in a car rated in mpg, drive in miles down the road, under a bridge measured in meters, go to the shops and buy a litre of milk, go to the pub and buy a pint of beer ....
Metric or Imperial .... we use both ....!
Re:Solution? (Score:4, Funny)
Re: (Score:3, Funny)
(dm^3)/(100*km) is fine, but I prefer to simplify by measuring gas consumption in square meters.
That might work for you, but I prefer simply measuring gas consumption by bankruptcies per vehicle.
Re:Solution? (Score:5, Insightful)
My Accord gets about 10L/100km, or 0.01m^3/100000m or 1e-7 m^2. This is equivalent to one tenth of a square millimetre.
Which means a strip of gasoline down the centre of the lane, with a cross-sectional area of one tenth of a square millimetre, would be enough to power my car as it drives.
Re:Solution? (Score:4, Insightful)
We're talking about North America, a typical vehicle gets 300 miles on a tank of gas. And 0 miles on a tank of diesel.
Re: (Score:3, Insightful)
For some reason, most US cars are sized to go about 350 miles per tank. Between my wife and I, we've gone through 10 cars (different makes, models, across 30 model years), and they've been that way. Low mpg? Put a big tank in it. High mpg? Put a little tank in it. You can (as an option) buy a larger tank, but I generally only see it in fleet vehicles. You can also buy a vehicle, and drive it differently than the manufacturer advertises. For example, my car is aimed at the commuting professional, as
Re: (Score:3, Informative)
You need to look at your math again. You are using numbers that are not even relevant to the example in the article.
100 miles at 10 mpg is 10 gallons of gas used. 100 miles at 20 mpg is 5 gallons of gas used. That's a savings of 5 gallons.
100 miles at 33 mpg is 3 gallons of gas used. 100 miles at 50 mpg is 2 gallons of gas used. That's a savings of 1 gallon of gas.
Looks to me like you plucked your numbers out of thin air.
The question is still absurd... (Score:5, Insightful)
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: (Score:2, Insightful)
Re: (Score:3, Insightful)
Who gives a care about % savings and if anyone misunderstands what this waste of science research reports if you ultimately understand basic facts about gasoline consumption.
This is like saying Americans are dumb because they should realize that an SUV/Truck is more efficient than a Toyota Corolla.
Re: (Score:3, Informative)
Re:The question is still absurd... (Score:4, Insightful)
Re: (Score:3, Informative)
However I found a couple of other newsreports, including this one [www.bt.no]; it is in Norwegian but I'll do some rough translations.
Quote:
"The reduction is diesel
Re:The question is still absurd... (Score:5, Informative)
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: (Score:3, Insightful)
Re:The question is still absurd... (Score:4, Insightful)
Indeed, the figures don't back him up either. The median age for a car in the United States is 9.2 years [bts.gov].
Re:The question is still absurd... (Score:4, Insightful)
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... (Score:5, Insightful)
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: (Score:3, Insightful)
Really, the biggest savings in America to be had are convincing people to give up their giant trucks and SUVs of all kinds. If you aren't uprooting trees with your truck on a weekly basis you don't need a vehicle where the HOOD is 3m off the ground.
Exagerated example [mlblogs.com] (The owner is a pitcher, he could probably drag a small stadium around with the thing.)
Re:The question is still absurd... (Score:4, Insightful)
Re:The question is still absurd... (Score:5, Insightful)
You don't exactly see your local plumber driving his supplies in an Escalade, though. GP's point is about SUVs etc owned by people who don't use that extra "utility", not actual utility vehicles used for actual utility.
Re: (Score:3, Insightful)
Actually, there are millions of people who really do need a larger vehicle.
Okay, let's say that "millions" is 10 million people. That's approximately 3% of the population. Are SUV's only 3% of the vehicles on the road?
Re:The question is still absurd... (Score:5, Interesting)
Re: (Score:3, Funny)
Perhaps you have no idea what they do when you're not watching them on the particular road you saw them on. Perhaps you don't see them when they're pulling a trailer, or hauling a soccer team around, or carrying three kayaks, etc.
When I see Debbie Soccermom driving a Yukon with a "(man) + (woman) + (kid)" sticker in the back window, I can state with 99% confidence that she doesn't pull trailers or tote kayaks around. Our minivan seats 2 adults and 5 kids comfortably.
I was driving the kids to school last year (we don't have buses and the local school isn't within walking distance) and started pointing out how many SUVs you saw with a woman driving and one kid in the rearmost seat. They picked up the meme and ran with it, kind of like
Re: (Score:3, Insightful)
I call BS. SUVs simply replaced station wagons for most people. A light SUV and all of those crossover variations aren't any worse than driving a minivan or a large passenger car
Re:The question is still absurd... (Score:4, Informative)
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... (Score:4, Insightful)
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... (Score:5, Informative)
Addition of 10% ethanol, which is common, does not have a significant impact on gas mileage and it certainly does not "destroy" it. A quick look at Wikipedia on energy density shows that a 90-10 gasoline-ethanol mix produces about 93% of the energy of pure gasoline. Now if you're talking about "flex-fuel" E85, then yeah, you're going to see a noticeable mileage drop. But that is not a common fuel.
Also ethanol acts as an oxygenate, to make the gas burn more completely and reduce carbon monoxide emissions. Pricewise - prior to oxygenating with ethanol, we were using MTBE anyhow, which has health risks and is a ground water contaminant.
So your post is mostly over-hyped nonsense. Now in a general sense, should corn be used to produce ethanol? No, and that's a result of the lobby that you mentioned. But they've affected much more than ethanol usage (see: high-fructose corn syrup and how they essentially killed sugarcane production in Hawaii).
Ethanol production from sugarcane, and to a lesser extent, beets, is much more energy efficient than corn.
Re:The question is still absurd... (Score:4, Interesting)
Now in a general sense, should corn be used to produce ethanol? No, and that's a result of the lobby that you mentioned.
There IS a benefit to using corn (for now). If we encourage ethanol use, then an infrastructure gets built up which can handle ethanol. When the cellulosic ethanol starts to become more widely available, that can replace the corn-based, and the infrastructure will be in place. It is a bet, to be sure, but seems to be much more realistic than the hydrogen proposals out there. Bio-diesel is also a strong contender, but there's already a infrastructure in place for that, and you still need a fuel for the cold-weather states.
Re:The question is still absurd... (Score:5, Insightful)
90-10 gasoline-ethanol mix produces about 93% of the energy of pure gasoline
In other words, the last 10% only gives you 3% more power?
Re:The question is still absurd... (Score:4, Interesting)
Re: (Score:3, Informative)
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: (Score:3, Insightful)
My 15 MPG car is very comfortable, has nice performance, and looks nice. I'm not buying a rattletrap 50MPH toaster, unless it saves me a lot of money. Actual dollar amounts saved might influence my purchasing decision - factors that are only important to those with other values obviously wouldn't.
Re: (Score:3, Insightful)
You miss the point.
You own 2 cars. a truck that gets 10MPG, a sedan that gets 33.
If you want to save fuel; do you upgrade the truck from 10 to 20, or the sedan from 33 to 50?
People who take the time to do the math, upgrading the truck would be the best answer.
Re: (Score:3, Insightful)
Re: (Score:3, Insightful)
Re: (Score:3, Interesting)
The correct answer is to subtract the inverse of the numbers:
1/10 - 1/20 = 0.10 - 0.05 = Saves 0.05 gallons per mile
1/33 - 1/50 = 0.03 - 0.02 = Saves 0.01 gallons per mile
Breaking! mlpm (Score:5, Insightful)
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 (Score:4, Interesting)
Of course, when cars fly, km won't be relevant because the international standard for aviation is nautical miles and velocity in knots.
Which is why (Score:2)
GP100M (Score:5, Insightful)
I always thought that measuring it Euro-way - in, for example, gallons per 100 miles - would me more practical and clear.
Re: (Score:2, Insightful)
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: (Score:3, Insightful)
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: (Score:3, Insightful)
MPG and GPM are both useful (Score:5, Insightful)
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 (Score:5, Informative)
High octane equals higher resistance to uncontrolled preignition (aka knock, or detonation). Higher resistance to preignition allows more advanced ignition timing. More advanced ignition equals higher cylinder pressures and longer burn duration. Higher cylinder pressure and longer burn duration allows more complete combustion and higher efficiency.
Modern vehicles with knock sensors can get greater efficiency from higher octane fuels due to their ability to keep ignition timing as advanced as possible without running into preignition.
Re:MPG and GPM are both useful (Score:5, Informative)
Two words: spark timing.
Many words: Higher octane gasolines are less likely to detonate (knock) at a given air charge temperature than a lower octane fuel. For high compression-ratio engines (those that say "93 Octane recommended" for instance), using a lower octane fuel will retard the spark timing (the spark will be later in the cycle) and reduce fuel economy, because energy available per combustion event is greater for earlier sparks (up to a point). However, if you have a car for which 87 octane is recommended, increasing octane won't really benefit you because the spark timing is already relatively late. Put another way: if you have a high compression engine, lower octane will retard your spark timing and reduce your fuel economy. If you have a low-compression engine, increasing octane won't improve your fuel economy because the spark timing will not increase.
Re:MPG and GPM are both useful (Score:5, Funny)
It's not like that? It's exactly like that. Your car has made you into an idiot.
Average Schmo's suck at math (Score:2)
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?
question is academic (Score:4, Insightful)
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.
Re:question is academic (Score:4, Insightful)
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.
I don't think it is academic, and I don't think most Americans find it academic either, because we have finite money. The question is not "is higher better?" but, rather, "how much higher is worth the extra price?" If you're choosing between replacing the family pickup truck or replacing the family sedan, and each of these replacements has a different cost, and each will also save a different amount of gasoline, how do you resolve that choice without knowing how much one option will save relative to the other? If you replace both, which do you pay a higher premium for? If you're willing to pay more for that 17mpg increase for the car than for the 10mpg increase for the truck, you're probably losing money. That's important in the real world.
2 in 3 cannot do arithmetic (Score:2)
Err..actually its the second one (Score:4, Insightful)
Actually, no (Score:4, Insightful)
Re:Err..actually its the second one (Score:5, Informative)
Unfortunately, the slashdot summary of the blog paraphrasing of the Duke study failed to spell out the real question which is: Given a two car family that have (and presumably needs) both an SUV and a commuter and both are driven 100 miles per week. Does it save more fuel to replace the 10 mpg SUV with a 20 mpg SUV, or the 33 mpg commuter with a 50 mpg commuter. Most people pick the wrong combination. Here's an example online test: MPG Illusion [mpgquiz.com]
mpg vs g for 100m (Score:3, Informative)
The European way:
Gazoline need for 100 miles:
@10 mpg: 10 gallons
@20 mpg: 5 gallons... saved: 5 gallons, 50%
@33 mpg: 3 gallons .... saved: 1 gallon, 33%
@50 mpg: 2 gallons
kinda more intuitive.
How about this math... (Score:3, Insightful)
Re:How about this math... (Score:4, Insightful)
Yes, of course. But how many 3 ton Suburbans do you see on the freeway during "rush" hour idling in stopped traffic with a single guy in it wearing a tie. He is not going to a construction job, hauling a load of bricks or a pallet of 50 25# sacks of tile grout, he is likely a financial analyst for some insurance company just trying to make it to the office. If he uses the capability of the vehicle ever, it is to move the boat from storage to the marina in the spring and haul it back to storage in the fall, something he could hire done for 1/100th of the cost of the Suburban. The number of these vehicles that are actually used to capacity is very small compared to the number sold. When they are, they are usually white and not "Amber Mist" and they have vinyl seats not leather and the come with an AM/FM radio not an eight channel sound system with dual sub-woofers. And they don't have $8000 worth of wheels and tires on them.
Back in the day, when I still had a strong back and worked putting up grain silos in eastern Montana, the company had a big, brown, 4 door, F350. When this thing went anywhere, it was loaded with a dozen large steel jack supports, a generator, a pile of electric impact tools, about 40 gallons of ice water, 4 or 5 workers and towing a trailer that had a big hydraulic pumping system with a dozen 4 foot long cylinders and about 400 feet of hose. This thing deserved to get 10 miles to the gallon, it provided value when it went anywhere. They also had a little Ford Courier that was used when only one or two people needed to go someplace or something small needed to be moved. While this thing didn't get anywhere near 50 mpg, it got way over 10. If they could have gotten a 50 mpg vehicle that would have held up to country roads in the mid 70's, they would have gotten one in a heart beat, because even though gas was under $1 per gallon, it would have paid off quickly because they racked up LOTS of miles. Eastern Montana is a big place and nothing is near anything else when you get out where they grow wheat.
Yes, context does matter. If you see someone who actually needs such a vehicle driving a Hummer, you have dropped into an alternate universe because it doesn't happen in real life.
Forget mpg. (Score:5, Funny)
Who cares? (Score:4, Insightful)
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.