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I will never understand why Americans keep using miles per gallon instead of liters per 100 km. Miles per gallon is only good if you want to advertise your car

I will never understand why Americans keep using miles per gallon instead of liters per 100 km. Miles per gallon is only good if you want to advertise your car ("look, with this car you can travel 50 miles with one gallon whereas with that one you can only travel 40 miles"). But you never do that in real life, you never fill your car with say, two gallons and say "now I'll travel 80 miles". Instead you always know the distance between two points and you want to know how much will that travel cost you. So you think like this: "distance from point A to point B is 250km, my car uses 6 liters per 100 km so I'll use 15 liters, 1 liter price is 2€ so it'll cost me 30€". Easy as pie and you can't do that with miles per gallon.

sdrothrock 11y ago
> So you think like this: "distance from point A to point B is 250 miles, my car gets 25 miles to the gallon, so I'll use 10 gallons, 1 gallon price is $3.00 so it'll cost me $30.00". Easy as pie. That's why. It's exactly the same thing you're talking about.
- obsurveyor 11y ago
  Yeah, it's the same mental arithmetic. These arguments just don't make sense for making some kind of change.
- sukilot 11y ago
  Nice cherrypick for that pie. And if your car gets 18 or 27 mpg, on a 230 mile trip? Multiplication is generally easier than division.
  - maxerickson 11y ago
    270-30 -> 9 gallons. Real answer, 8.52 gallons. 230 / 20 -> 11.5 gallons. Real answer, 12.2 gallons (and I would know to fudge up). So it is still easy to estimate to within $5.
- perakojotgenije 11y ago
  Because it's easier for an average person to multiply than to divide.
benihana 11y ago
>I'll never understand why different [organizational unit] does things differently than me. My way is superior because I've formed a mental model of it.
- sukilot 11y ago
  In actual real life human decision making, one of the models generates more accurate answer. Humans are estimators.
  - deleted 11y ago
    [deleted]
superuser2 11y ago
If people start thinking of individual car trips as spending money (rather than the generalized cost of having a car), I wouldn't be surprised if people drastically reduced their travel and, correspondingly, consumption (by not leaving their houses). People seem to highly resistant to impulse purchases for dollar amounts smaller than they are willing to spend on road travel without thinking. This would be a Very Bad Thing for the American economy, so I'm not surprised that we are encouraged to reason about gas milage in language that makes this more difficult.
- ghaff 11y ago
  Who is doing this encouraging "to reason about gas milage in language that makes this more difficult"? MPG as a fuel efficiency metric goes back many decades. I don't actually disagree that that if there were a big ticking dollar gauge that tallied up the cost of each trip in a car, some people might drive less. But it's not the reason we use the MPG metric.
  - dec0dedab0de 11y ago
    a big ticking dollar gauge that tallied up the cost of each trip in a car That sounds like a fun project.
  - dragonwriter 11y ago
    > I don't actually disagree that that if there were a big ticking dollar gauge that tallied up the cost of each trip in a car, some people might drive less. Some cars already have those (well, not necessarily big and ticking, but, some have a fuel-cost-of-trip measure that is displayed, either on one of the information screens or when you end a trip, or both.)
ugexe 11y ago
It's just as simple doing the same conversion for mpg. If I'm going 250 miles and get 25mph I instantly know that's 10 gallons multiplied by whatever the cost of fuel is
maxerickson 11y ago
The thing about mpg that is problematic is that it obfuscates the savings in going from a 10-20 mpg vehicle to a 20-30 mpg vehicle (and exaggerates the benefits of a 50 mpg vehicle). 15 mpg -> 25 mpg is a much bigger step than 25 mpg -> 35 mpg (a savings of 2.6 gallons per 100 miles vs a savings of 1.15 gallons per 100 miles). The jump from 35 mpg to 50 mpg only saves 0.85 gallons per 100 miles. For everything else it just introduces some trivial difference in the arithmetic.
- mc32 11y ago
  This is a great point, but except for policy makers, where this information matters, to say, incentivize mfgs, or consumers with rebates, this context is not practical in day to day dealings of most drivers. Perhaps publish the information in both formats.
- astolarz 11y ago
  To me, this is the best argument for l/100km (or gal/100mi). I don't know of anyone who really thinks about how far they can go before they have to refuel. They just check the gas gauge and fill up when it's low. There's very few places, even in the US, without a nearby gas station so it's not really much of an issue. The arguments about multiplication vs. division also seem silly, especially since your math teacher lied about not always having a calculator. That said, as an American I grew up with MPG so that's what's intuitive to me and I'm happy with it. Something like l/100km seems like it would be mostly useful when shopping for a car than actually getting around.
- dragonwriter 11y ago
  > The thing about mpg that is problematic is that it obfuscates the savings in going from a 10-20 mpg vehicle to a 20-30 mpg vehicle (and exaggerates the benefits of a 50 mpg vehicle). I think the EPA's estimated-fuel-cost-per-year (based on standardized assumption), which I believe is part of the standard rating disclosure for new vehicles just like MPG is, addresses for most consumers that better than MPG or gal/100mi, and for the subset of consumers for whom it isn't better -- i.e., the ones that have good numbers on their own usage patterns that they are going to calculate out from to get a personalized estimate -- MPG and gal/100mi are exactly equal in utility.
abruzzi 11y ago
MPG is useful when you are thinking in terms of vehicle range. This isn't most people's default, but it does have its usefulness. As for why US doesn't use l/100km. the simplest answer is all our vehicle odometers are calibrated in miles, and we buy gasoline in gallons, so l/100km is a number with no grounding. To get most people in the US looking at it it would have to be gal/100miles or similar.
- ascorbic 11y ago
  Confusingly, the UK also uses mpg despite the fact we buy fuel in litres.
  - Ntrails 11y ago
    Our odometers are in miles though - so it's not completely mindbogglingly stupid. In the end realistically almost no one uses these numbers for range, what they do is compare car A to car B and know that higher is better. The figures from the manufacturer are meaningless and anything with an on board computer telling you your mpg can just as easily tell you range on remaining fuel.
- alwaysdoit 11y ago
  I mean, if your question is Can I go 300 miles? 1/25 GPM * 300 Miles = 12 gallons Which is either larger or smaller than your gas tank, so I think fuel volume over distance traveled is still easy enough to use for the range calculation, and better for almost everything else.
  - com2kid 11y ago
    I can't necessarily do that math in my head. "I have 40 miles roundtrip of errands to run today, and 3 gallons of gas left, do I have to fill up before I leave and maybe be late to my first appointment or am I good for the day?" Well at 20mpg the answer is really easy. 3*20-->60, I'm good.
    - obsurveyor 11y ago
bitwize 11y ago
The USA is BIG. Foreigners who come here often have little idea what an unfathomably huge place the USA is. And unlike say, Russia or Canada which are even bigger geographically, virtually all of that territory is navigable by car throughout much of the year. In the USA, therefore, it was historically pretty likely that grandma and grandpa lived far away, say, back at the farm while mom and dad moved into the big city or the suburbs to get jobs and raise a family. So in America there was a much bigger market for grand tourers -- cars designed to go long distances and be fun to drive. Early consumer automobiles were promoted as such -- "See the USA in your Chevrolet" and the like. Now you know why American cars are reputedly so big and ugly: in Europe GTs are rich boy toys whereas in America they had to appeal to middle-class sensibilities which meant things like big engines and rocket fins on the rear and such. So in this environment, it made much more sense to market a fuel-economical car not with statements like "you can use less fuel and save money over your trips to the market and to work" -- oil was cheap at least until the 1970s -- but with statements like "you can go this much further on a single tank of gas". Hence the metric of miles per gallon, rather than litres per 100km or gallons per 100 miles -- which is still in use today.
- maxerickson 11y ago
  Gas is still cheap: http://inflationdata.com/inflation/images/charts/oil/gasoline_inflation_chart.htm http://inflationdata.com/inflation/images/charts/oil/gasolin... (Inflation happens to be a well used purchasing power adjustment, I think comparisons of the cost of gasoline will survive others.)
- galago 11y ago
  I've never been to Europe, and I'm actually curious if the Eurozone has changed driving behavior much. Would it be unusual for someone in Berlin to drive to Rome or Athens on vacation? For similar distances in the USA my experience is that it would be common, partly because Americans like to have their car when they arrive. Even when gas prices were quite a bit higher Americans still drove. Who gets in a car and only burns one gallon of gas? An F150 only gets about 20mpg, and I know people who go farther than that for groceries.
Kluny 11y ago
I'm Canadian and buy litres of gas, but I still check the mileage in mpg. It's just because I have an instinctive idea of how many mpg I should get, whereas I have no instinct for l/100km. I know 35mpg is decent and 50mpg is exceptional, and 10mpg is unacceptable. What does 10L per 100km mean? I have no idea.
- _lce0 11y ago
  I can understand that it's not intuitive for you, but for me it's all the way round, so it's just everybody's bias according to different cultures btw, moving between unit is simple math: 35 MPG: ------- 35 miles ... 1 gallon 100 miles ... x gallon = 100 * 1 / 35 [gallon] -> ~2.86 gallons/100 miles .. and, look mom, no math! 10 L per 100 KM: ---------------- 10 l ... 100 Km 1 l ... x Km -> 10 Kms per liter .. which now that you think.. made sense for "10L per 100Km", isn't? that's the power of MKS
petercooper 11y ago
I'm British and prefer mpg. Why? Because for starters kilometres are alien to me, but also because it's just familiar and relatable. But with that said, the numbers manufacturers give are never even vaguely useful IMHO (my car is technically 40mpg but I get low 20s) so it's more for comparison of efficiency between journeys than anything else.
dragonwriter 11y ago
> I will never understand why Americans keep using miles per gallon instead of liters per 100 km. Because: (1) neither liters nor km or meaningful measures to Americans in general; were Americans going to use a measure of fuel:distance, it might be gallons per 100 miles, but not liters per 100 km, and (2) Even then, I think there's a pretty strong preference for more-is-better measures rather than less-is-better. > Miles per gallon is only good if you want to advertise your car That's pretty much the only thing MPG ratings are used for, manufacturers selling cars. So, its not really surprising that that is what is used. > But you never do that in real life, you never fill your car with say, two gallons and say "now I'll travel 80 miles". No one I know ever do the reverse, either; you don't decide "I'm going to go eighty miles, and this car consumes 2 gallons per 100 miles, so I need to make sure the taken has at least 2×80/100 = 1.6 gallons". > Instead you always know the distance between two points and you want to know how much will that travel cost you. For people who care about that, there is a reason that auto magazines doing reviews often publish things like total per-mile fuel + maintenance costs for reviewed vehicles. If you just care about fuel costs, it takes about as much work (same number of multiplications and divisions, just changes which figures are being multiplied and which divided) to calculate that from MPG and gas price as it does from gal/mi (or gal/100mi) and gas price, so there's no real advantage to using one over the other for that purpose. (And, IME in practice, fuel costs are usually a concern with trips where the consumption consideration isn't "how many gallons will I get based on the cars stated ratings" but "how many tanks will it take based on my driving experience", in which case the people using it often are using something like the miles per unit of fuel ratings, but the rating is determined by experience with the vehicle, and the unit is whole fuel tanks.)
rebootthesystem 11y ago
Sorry, this is a non-argument because you are trying to solve a non-existing problem. The calculation used to determine range or cost when you have miles-per-gallon or km-per-liter is trivial and just as familiar as the liters-per-distance calculation when viewed in context. My point is that if you actually LIVE in an environment where miles-per-gallon is the norm you develop familiarity with the numbers. You develop a sense of proportion. The calculations are not difficult because they are normal to you. To anyone transitioning back and forth between the two systems, well, there will have to be an adaptation period during which things will be uncomfortable until they are not. Besides, people very rarely have to make these calculations today. My car tells me how many miles I have left in the tank based on the average historical fuel consumption since I've owned it. No math required. When I fill up, it updates that number. Still, you very quickly learn that you get X number of miles with a full tank of gas. You just know that. You also learn you need to refill your tank N number of times in the course of a month on average due to your normal driving patterns. None of this requires much thought. And, if you are going on a long trip you generally know how far you can go on a single tank of gas and hopefully you've verified that there are gas stations along the route to top-off as you go (which in the US is generally the case). As far as calculating the cost of a trip, again, if you live in miles-per-gallon land it is easy. Nobody goes into a crying frenzy screaming "Why, oh why don't we use liters per 100 km. This is so hard!". No, instead people have an estimate of their average miles-per-gallon or an accurate historical average from their car's information display system. They get the distance to their destination and divide. And, no, there's no need to divide 483.5 miles by 21.3 miles-per-gallon. That's insane. Nobody does that. Your goal is to get a sense of proportion of how much fuel you'll need. So, you divide 500 by 20 and you'll get a decent number. It won't be twice that many gallons nor half. There are plenty of gas stations along the route. No worries. And, if you need an accurate number for reimbursement purposes, well, keep the receipts. So, again, I think you are trying to solve a non-existing problem. Now, on the question of metric vs. imperial. Well, I detest the imperial system of units. I hate it. I use metric for engineering purposes. The world is metric. It is ridiculous that we haven't made the switch. That said, I fully understand why. Unless you've traveled through the US it is hard to get a sense of proportion. This place is huge. The infrastructure is of unimaginable proportions. Going metric could very well take 100 years due to the sheer amount of work and cost involved. So, yeah, I get it. There are other seemingly minor examples of this. We sell internationally so I am very aware of cultural and systemic differences. For example, most of the world would write one thousand dollars like this: $1.000,00. In the US it is written like this: $1,000.00. In the US 1/2/2015 means January 2nd, 2015. In the rest of the world it means February 1st, 2015. In the US we use AM and PM. In a good deal of the world it is a 24 hour clock (which makes far more sense). There are a lot more examples of this. If we can't fix something as simple as what the comma and period mean when speaking about money or the order of the day and month on a date we are doomed to fail in shifting the US to the metric system.
drzaiusapelord 11y ago
Only on HN would a stupid "herp derp you guys are using the wrong metrics" post be voted this highly. I get it, snotty Eurpeans get snotty upvotes from each other with their snotty, "We dont like your imperial units" whining on the internet. Umm, congrats? The rest of your argument is bunk as its trivial to find out what your gas capacity is and know your max range is. Most people don't worry about how much it will cost to drive to grandma's cost. Also, gas is cheap and Americans are wealthy. We don't buy one or two gallons and walk away hoping to get through the weekend. We typically fill our tanks and off we go. Long drives are the norm here as you may have friends/relatives in the suburbs or out of state. On top of it, our geography is HUGE and unlike "big" countries like Russia or China or Canada its almost all drivable/livable/usable. Knowing your range is more important to most people than knowing how much it costs to get to grandma's house. Its in your countries where gas is super-expensive that you have to worry about those things. Not here, at least for most people. MPG is a perfectly rational way to talk about car efficiency, even in everyday use. Considering the typical IT automation in cars nowadays, this argument is academic as you can trivially bring up up all sorts of info on the console. Sorry, but the usual "the Euro way is the only and the best way" whining is wrong again. Turns out there are lots of good ways to do things and "good" is relative to the needs and expectations of the user.
- lkbm 11y ago
  When buying a car, the difference between 10mpg and 20mpg looks the same as the difference between 20mpg and 30mpg. This is the usual complaint.
  - drzaiusapelord 11y ago
    Can you even get a 10-20mpg car without resorting to niche items like heavy trucks and such, where the buy would be fairly sophisticated in fuel usage considering its pretty much a work truck? This probably isn't too big of a concern from a practical standpoint. Avg fuel economy in the USA in 2014 is 24.1. Changes from there are small increments, ignoring hybrids and ultra-efficient vehicles.
pontifier 11y ago
For a while, I avoided using gallons at all. I'd drive a hundred miles, then fill up. Then dollars to fill up = cents per mile. Now I just put 5 bucks in when I can afford it.

sdrothrock 11y ago

> So you think like this: "distance from point A to point B is 250 miles, my car gets 25 miles to the gallon, so I'll use 10 gallons, 1 gallon price is $3.00 so it'll cost me $30.00". Easy as pie. That's why. It's exactly the same thing you're talking about.

obsurveyor 11y ago
Yeah, it's the same mental arithmetic. These arguments just don't make sense for making some kind of change.
sukilot 11y ago
Nice cherrypick for that pie. And if your car gets 18 or 27 mpg, on a 230 mile trip? Multiplication is generally easier than division.
- maxerickson 11y ago
  270-30 -> 9 gallons. Real answer, 8.52 gallons. 230 / 20 -> 11.5 gallons. Real answer, 12.2 gallons (and I would know to fudge up). So it is still easy to estimate to within $5.
perakojotgenije 11y ago
Because it's easier for an average person to multiply than to divide.

benihana 11y ago

>I'll never understand why different [organizational unit] does things differently than me. My way is superior because I've formed a mental model of it.

sukilot 11y ago
In actual real life human decision making, one of the models generates more accurate answer. Humans are estimators.
- deleted 11y ago
  [deleted]

superuser2 11y ago

If people start thinking of individual car trips as spending money (rather than the generalized cost of having a car), I wouldn't be surprised if people drastically reduced their travel and, correspondingly, consumption (by not leaving their houses). People seem to highly resistant to impulse purchases for dollar amounts smaller than they are willing to spend on road travel without thinking. This would be a Very Bad Thing for the American economy, so I'm not surprised that we are encouraged to reason about gas milage in language that makes this more difficult.

ghaff 11y ago
Who is doing this encouraging "to reason about gas milage in language that makes this more difficult"? MPG as a fuel efficiency metric goes back many decades. I don't actually disagree that that if there were a big ticking dollar gauge that tallied up the cost of each trip in a car, some people might drive less. But it's not the reason we use the MPG metric.
- dec0dedab0de 11y ago
  a big ticking dollar gauge that tallied up the cost of each trip in a car That sounds like a fun project.
- dragonwriter 11y ago
  > I don't actually disagree that that if there were a big ticking dollar gauge that tallied up the cost of each trip in a car, some people might drive less. Some cars already have those (well, not necessarily big and ticking, but, some have a fuel-cost-of-trip measure that is displayed, either on one of the information screens or when you end a trip, or both.)

ugexe 11y ago

It's just as simple doing the same conversion for mpg. If I'm going 250 miles and get 25mph I instantly know that's 10 gallons multiplied by whatever the cost of fuel is

maxerickson 11y ago

The thing about mpg that is problematic is that it obfuscates the savings in going from a 10-20 mpg vehicle to a 20-30 mpg vehicle (and exaggerates the benefits of a 50 mpg vehicle). 15 mpg -> 25 mpg is a much bigger step than 25 mpg -> 35 mpg (a savings of 2.6 gallons per 100 miles vs a savings of 1.15 gallons per 100 miles). The jump from 35 mpg to 50 mpg only saves 0.85 gallons per 100 miles. For everything else it just introduces some trivial difference in the arithmetic.

mc32 11y ago
This is a great point, but except for policy makers, where this information matters, to say, incentivize mfgs, or consumers with rebates, this context is not practical in day to day dealings of most drivers. Perhaps publish the information in both formats.
astolarz 11y ago
To me, this is the best argument for l/100km (or gal/100mi). I don't know of anyone who really thinks about how far they can go before they have to refuel. They just check the gas gauge and fill up when it's low. There's very few places, even in the US, without a nearby gas station so it's not really much of an issue. The arguments about multiplication vs. division also seem silly, especially since your math teacher lied about not always having a calculator. That said, as an American I grew up with MPG so that's what's intuitive to me and I'm happy with it. Something like l/100km seems like it would be mostly useful when shopping for a car than actually getting around.
dragonwriter 11y ago
> The thing about mpg that is problematic is that it obfuscates the savings in going from a 10-20 mpg vehicle to a 20-30 mpg vehicle (and exaggerates the benefits of a 50 mpg vehicle). I think the EPA's estimated-fuel-cost-per-year (based on standardized assumption), which I believe is part of the standard rating disclosure for new vehicles just like MPG is, addresses for most consumers that better than MPG or gal/100mi, and for the subset of consumers for whom it isn't better -- i.e., the ones that have good numbers on their own usage patterns that they are going to calculate out from to get a personalized estimate -- MPG and gal/100mi are exactly equal in utility.

abruzzi 11y ago

MPG is useful when you are thinking in terms of vehicle range. This isn't most people's default, but it does have its usefulness. As for why US doesn't use l/100km. the simplest answer is all our vehicle odometers are calibrated in miles, and we buy gasoline in gallons, so l/100km is a number with no grounding. To get most people in the US looking at it it would have to be gal/100miles or similar.

ascorbic 11y ago
Confusingly, the UK also uses mpg despite the fact we buy fuel in litres.
- Ntrails 11y ago
  Our odometers are in miles though - so it's not completely mindbogglingly stupid. In the end realistically almost no one uses these numbers for range, what they do is compare car A to car B and know that higher is better. The figures from the manufacturer are meaningless and anything with an on board computer telling you your mpg can just as easily tell you range on remaining fuel.
alwaysdoit 11y ago
I mean, if your question is Can I go 300 miles? 1/25 GPM * 300 Miles = 12 gallons Which is either larger or smaller than your gas tank, so I think fuel volume over distance traveled is still easy enough to use for the range calculation, and better for almost everything else.
- com2kid 11y ago
  I can't necessarily do that math in my head. "I have 40 miles roundtrip of errands to run today, and 3 gallons of gas left, do I have to fill up before I leave and maybe be late to my first appointment or am I good for the day?" Well at 20mpg the answer is really easy. 3*20-->60, I'm good.
  - obsurveyor 11y ago

bitwize 11y ago

The USA is BIG. Foreigners who come here often have little idea what an unfathomably huge place the USA is. And unlike say, Russia or Canada which are even bigger geographically, virtually all of that territory is navigable by car throughout much of the year. In the USA, therefore, it was historically pretty likely that grandma and grandpa lived far away, say, back at the farm while mom and dad moved into the big city or the suburbs to get jobs and raise a family. So in America there was a much bigger market for grand tourers -- cars designed to go long distances and be fun to drive. Early consumer automobiles were promoted as such -- "See the USA in your Chevrolet" and the like. Now you know why American cars are reputedly so big and ugly: in Europe GTs are rich boy toys whereas in America they had to appeal to middle-class sensibilities which meant things like big engines and rocket fins on the rear and such. So in this environment, it made much more sense to market a fuel-economical car not with statements like "you can use less fuel and save money over your trips to the market and to work" -- oil was cheap at least until the 1970s -- but with statements like "you can go this much further on a single tank of gas". Hence the metric of miles per gallon, rather than litres per 100km or gallons per 100 miles -- which is still in use today.

maxerickson 11y ago
Gas is still cheap: http://inflationdata.com/inflation/images/charts/oil/gasoline_inflation_chart.htm http://inflationdata.com/inflation/images/charts/oil/gasolin... (Inflation happens to be a well used purchasing power adjustment, I think comparisons of the cost of gasoline will survive others.)
galago 11y ago
I've never been to Europe, and I'm actually curious if the Eurozone has changed driving behavior much. Would it be unusual for someone in Berlin to drive to Rome or Athens on vacation? For similar distances in the USA my experience is that it would be common, partly because Americans like to have their car when they arrive. Even when gas prices were quite a bit higher Americans still drove. Who gets in a car and only burns one gallon of gas? An F150 only gets about 20mpg, and I know people who go farther than that for groceries.

Kluny 11y ago

I'm Canadian and buy litres of gas, but I still check the mileage in mpg. It's just because I have an instinctive idea of how many mpg I should get, whereas I have no instinct for l/100km. I know 35mpg is decent and 50mpg is exceptional, and 10mpg is unacceptable. What does 10L per 100km mean? I have no idea.

_lce0 11y ago
I can understand that it's not intuitive for you, but for me it's all the way round, so it's just everybody's bias according to different cultures btw, moving between unit is simple math: 35 MPG: ------- 35 miles ... 1 gallon 100 miles ... x gallon = 100 * 1 / 35 [gallon] -> ~2.86 gallons/100 miles .. and, look mom, no math! 10 L per 100 KM: ---------------- 10 l ... 100 Km 1 l ... x Km -> 10 Kms per liter .. which now that you think.. made sense for "10L per 100Km", isn't? that's the power of MKS

petercooper 11y ago

I'm British and prefer mpg. Why? Because for starters kilometres are alien to me, but also because it's just familiar and relatable. But with that said, the numbers manufacturers give are never even vaguely useful IMHO (my car is technically 40mpg but I get low 20s) so it's more for comparison of efficiency between journeys than anything else.

dragonwriter 11y ago

> I will never understand why Americans keep using miles per gallon instead of liters per 100 km. Because: (1) neither liters nor km or meaningful measures to Americans in general; were Americans going to use a measure of fuel:distance, it might be gallons per 100 miles, but not liters per 100 km, and (2) Even then, I think there's a pretty strong preference for more-is-better measures rather than less-is-better. > Miles per gallon is only good if you want to advertise your car That's pretty much the only thing MPG ratings are used for, manufacturers selling cars. So, its not really surprising that that is what is used. > But you never do that in real life, you never fill your car with say, two gallons and say "now I'll travel 80 miles". No one I know ever do the reverse, either; you don't decide "I'm going to go eighty miles, and this car consumes 2 gallons per 100 miles, so I need to make sure the taken has at least 2×80/100 = 1.6 gallons". > Instead you always know the distance between two points and you want to know how much will that travel cost you. For people who care about that, there is a reason that auto magazines doing reviews often publish things like total per-mile fuel + maintenance costs for reviewed vehicles. If you just care about fuel costs, it takes about as much work (same number of multiplications and divisions, just changes which figures are being multiplied and which divided) to calculate that from MPG and gas price as it does from gal/mi (or gal/100mi) and gas price, so there's no real advantage to using one over the other for that purpose. (And, IME in practice, fuel costs are usually a concern with trips where the consumption consideration isn't "how many gallons will I get based on the cars stated ratings" but "how many tanks will it take based on my driving experience", in which case the people using it often are using something like the miles per unit of fuel ratings, but the rating is determined by experience with the vehicle, and the unit is whole fuel tanks.)

rebootthesystem 11y ago

Sorry, this is a non-argument because you are trying to solve a non-existing problem. The calculation used to determine range or cost when you have miles-per-gallon or km-per-liter is trivial and just as familiar as the liters-per-distance calculation when viewed in context. My point is that if you actually LIVE in an environment where miles-per-gallon is the norm you develop familiarity with the numbers. You develop a sense of proportion. The calculations are not difficult because they are normal to you. To anyone transitioning back and forth between the two systems, well, there will have to be an adaptation period during which things will be uncomfortable until they are not. Besides, people very rarely have to make these calculations today. My car tells me how many miles I have left in the tank based on the average historical fuel consumption since I've owned it. No math required. When I fill up, it updates that number. Still, you very quickly learn that you get X number of miles with a full tank of gas. You just know that. You also learn you need to refill your tank N number of times in the course of a month on average due to your normal driving patterns. None of this requires much thought. And, if you are going on a long trip you generally know how far you can go on a single tank of gas and hopefully you've verified that there are gas stations along the route to top-off as you go (which in the US is generally the case). As far as calculating the cost of a trip, again, if you live in miles-per-gallon land it is easy. Nobody goes into a crying frenzy screaming "Why, oh why don't we use liters per 100 km. This is so hard!". No, instead people have an estimate of their average miles-per-gallon or an accurate historical average from their car's information display system. They get the distance to their destination and divide. And, no, there's no need to divide 483.5 miles by 21.3 miles-per-gallon. That's insane. Nobody does that. Your goal is to get a sense of proportion of how much fuel you'll need. So, you divide 500 by 20 and you'll get a decent number. It won't be twice that many gallons nor half. There are plenty of gas stations along the route. No worries. And, if you need an accurate number for reimbursement purposes, well, keep the receipts. So, again, I think you are trying to solve a non-existing problem. Now, on the question of metric vs. imperial. Well, I detest the imperial system of units. I hate it. I use metric for engineering purposes. The world is metric. It is ridiculous that we haven't made the switch. That said, I fully understand why. Unless you've traveled through the US it is hard to get a sense of proportion. This place is huge. The infrastructure is of unimaginable proportions. Going metric could very well take 100 years due to the sheer amount of work and cost involved. So, yeah, I get it. There are other seemingly minor examples of this. We sell internationally so I am very aware of cultural and systemic differences. For example, most of the world would write one thousand dollars like this: $1.000,00. In the US it is written like this: $1,000.00. In the US 1/2/2015 means January 2nd, 2015. In the rest of the world it means February 1st, 2015. In the US we use AM and PM. In a good deal of the world it is a 24 hour clock (which makes far more sense). There are a lot more examples of this. If we can't fix something as simple as what the comma and period mean when speaking about money or the order of the day and month on a date we are doomed to fail in shifting the US to the metric system.

drzaiusapelord 11y ago

Only on HN would a stupid "herp derp you guys are using the wrong metrics" post be voted this highly. I get it, snotty Eurpeans get snotty upvotes from each other with their snotty, "We dont like your imperial units" whining on the internet. Umm, congrats? The rest of your argument is bunk as its trivial to find out what your gas capacity is and know your max range is. Most people don't worry about how much it will cost to drive to grandma's cost. Also, gas is cheap and Americans are wealthy. We don't buy one or two gallons and walk away hoping to get through the weekend. We typically fill our tanks and off we go. Long drives are the norm here as you may have friends/relatives in the suburbs or out of state. On top of it, our geography is HUGE and unlike "big" countries like Russia or China or Canada its almost all drivable/livable/usable. Knowing your range is more important to most people than knowing how much it costs to get to grandma's house. Its in your countries where gas is super-expensive that you have to worry about those things. Not here, at least for most people. MPG is a perfectly rational way to talk about car efficiency, even in everyday use. Considering the typical IT automation in cars nowadays, this argument is academic as you can trivially bring up up all sorts of info on the console. Sorry, but the usual "the Euro way is the only and the best way" whining is wrong again. Turns out there are lots of good ways to do things and "good" is relative to the needs and expectations of the user.

lkbm 11y ago
When buying a car, the difference between 10mpg and 20mpg looks the same as the difference between 20mpg and 30mpg. This is the usual complaint.
- drzaiusapelord 11y ago
  Can you even get a 10-20mpg car without resorting to niche items like heavy trucks and such, where the buy would be fairly sophisticated in fuel usage considering its pretty much a work truck? This probably isn't too big of a concern from a practical standpoint. Avg fuel economy in the USA in 2014 is 24.1. Changes from there are small increments, ignoring hybrids and ultra-efficient vehicles.

pontifier 11y ago

For a while, I avoided using gallons at all. I'd drive a hundred miles, then fill up. Then dollars to fill up = cents per mile. Now I just put 5 bucks in when I can afford it.