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2 In 3 Misunderstand Gas Mileage; Here's Why
thecarchik sends in this piece, which was published last March but remains timely: "OK, so here's a little test: Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg? If you're like most Americans, you picked the second one. But, in fact, that's exactly backwards. Over any given mileage, replacing a 10-mpg vehicle with one that gets 20 mpg saves five times the gasoline that replacing a 33-mpg vehicle with one that gets 50 does. Last summer, Duke University's Fuqua School of Business released a study that shows how much damage comes from using MPG instead of consumption to measure how green a car is. Management professors Richard Larick and Jack Soll's experiments proved that consumers thought fuel consumption was cut at an even rate as mileage increased."
News at 11!
I get that the 1st one is a 100% increase while the other is only 50% but you still get a better deal and less pollution by buying the 50 mpg car (if the price is the same).
So which saves more gasoline? the 2nd one ...
Breaking: In an astounding fit of partial international cooperation and scientific rationality, the US adopts a mostly metric measure of resource use: the milliliter per mile, or the mlpm
For example:
10MPG = 378 mlpm
20MPG = 189 mlpm
33MPG = 115 mlpm
50MPG = 76 mlpm
90MPG = 42 mlpm
The unit is linear, easy to understand, with numbers everyone can grasp (40-400 ish), and most important, it slowly creeps the US mind toward the metric system, one small step at a time! What a breakthrough! When the cars fly, we can try for using km, not miles.
Also, mlpm helps put the idea that gasoline is a great resource, to be used sparingly, by the milliliter, as opposed to "by the gallon" like 7eleven slurpies.
Sadly, in all seriousness, from TFA "Consumption instead of mileage? Nah. Dumb idea. Never work. [sigh]" Probably have to agree with this. Not because it's a dumb idea, but because Americans with the social and business systems in place have shown repeatedly that they will hold onto current ideas so strongly even in the face of overwhelming and obvious evidence showing them to be wrong. Only the real American idol will effect real change in the US system, the dollar.
I always thought that measuring it Euro-way - in, for example, gallons per 100 miles - would me more practical and clear.
Though it may not be obvious why to someone in a metropolitan area or Europe.
MPG is the more useful number when you need to figure out what the range of a vehicle is (and perhaps if you'll be able to reach the next station). In the western US it's not unheard of to find yourself 100 miles from any gas station.
"Prefiero morir de pie que vivir siempre arrodillado!"
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.
No good deed goes unpunished...
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.
Which saves more gasoline, going from 10 to 20 mpg, or going from 33 to 50 mpg?
people answer incorrectly because the question is academic. what matters is that people know a higher MPG is better, which i think almost everyone does.
If you go from 10 to 20 mpg, youre still less than the 33 mpg lower limit in the second case, so the second option "saves more gas". If the question is "which is a bigger improvement in fuel economy", then the answer is the first one.
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.
In fact, the two cases are not interchangeable. Suppose the problem is dressed up a little: you have two cars that you use on a regular basis (this is not negotiable), but only enough money to replace one of them. One car gets 33MPG, and the other gets 10MPG. If you replace the 33MPG car, you can get a 50MPG vehicle. If you replace the 10MPG, you can get a 20MPG vehicle. Which would save more gas, replacing the 33MPG car or the 10MPG car?
Palm trees and 8
No. Here is why. I consider it a stupid tax. Like the lottery. We need more stupid taxes. Down with the stupid.
Why is it so hard to only have politicians for a few years, then have them go away?
Clearly, what we need here is a car analogy!
Anyone?
Cheers,
"What in the name of Fats Waller is that?"
"A four-foot prune."
Of course, when cars fly, km won't be relevant because the international standard for aviation is nautical miles and velocity in knots.
--Jim (me)
My car gets 40 rods to the hogshead and that's the way I likes it.
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.
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)
(T>t && O(n)--) == sqrt(666)
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.
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.
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.
* Winners compare their achievements to their goals, losers compare theirs to that of others.
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.
Outside the US & UK, fuel consumption for cars, trucks, etc, is normally expressed as Liters per 100 kilometers. This completely avoids the non-issue that TFA is grumbling about, even for innumerate consumers, since the numbers represent fuel used in a trip of 100km.
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).
Those who can make you believe absurdities can make you commit atrocities. - Voltaire
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.
“Common sense is not so common.” — Voltaire
..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 ....!
Puteulanus fenestra mortis