Gallons per 100 miles

[D189379]

I don't really see the point in changing. You're just changing the math. Most people can figure out how far they can go if their car gets 30mpg and their tank holds 20 gallons far easier than they can figuring it out using 3.333 gallons per 100 miles.

30x20 = 600

or

(20/3.333)x 100 = 600

So very simple math vs slightly less simple math.

I don't have any trouble figuring these calculations out, but I don't know how to compare the numbers in my head. Right off the bat I know 10mpg is pretty bad, 20mpg is about normal, 30mpg is pretty good, and 40mpg is great. It makes sense to me.

Throw in the fact that I'm in Canada and most fuel economy is in Liters per 100km, half of our tv commercials are US stations and I constantly hear mpg, and to be even more confusing Canadian manufacturers also post mpg figures using an imperial gallon vs a US gallon, which is larger, which confuses things even more.

So I can be watching NBC, watch a commercial for a new Chevy Truck that gets 21mpg, flip to a Canadian channel, and there's a Chevy Truck that advertises 29mpg.

Confusion and deception.

I always covert my mileage to US mpg. It works. I understand it.

 

[Cujet]

Ya know, my Cessna 177rg gets about 17 miles per gallon in high speed cruise. It's critical to understand this intuitively. And about 25mpg in its most efficient configuration. I carry 50 gallons.

Really, I don't care to calculate how much fuel it uses per 100 miles. I never fly any multiple of 100 miles.

 

[Quattro Pete]

Originally Posted By: D189379
I don't have any trouble figuring these calculations out, but I don't know how to compare the numbers in my head. Right off the bat I know 10mpg is pretty bad, 20mpg is about normal, 30mpg is pretty good, and 40mpg is great. It makes sense to me.

The problem with MPG is that it is not linear and therefore it tends to cloud people's vision when trying to use fuel economy as a significant factor in new car shopping. In your example above, going from 10 mpg to 20 mpg is a much greater fuel economy benefit than going from 30 mpg to 40 mpg.

Say you've got two vehicles in your household, one gets 10 mpg and the other one gets 30 mpg. It's time to get one of them replaced, and the household wonders which one to replace. They may think that replacing the 30 mpg with a 40 mpg one will be just as beneficial as replacing the 10 mpg with a 20 mpg, and that's clearly not the case.

Granted, one also needs to look at total miles driven in addition to fuel economy, as the other posted noted.

 

[Quattro Pete]

Originally Posted By: Cujet
Really, I don't care to calculate how much fuel it uses per 100 miles. I never fly any multiple of 100 miles.

Certainly, what works for cars doesn't necessarily work for planes, boats, or other modes of transportation.

 

[Vikas]

As Click and Clack would say :---- Boooooogggggguuuuuuuusssss

The guys who think "replacing the 30 mpg with a 40 mpg one will be just as beneficial as replacing the 10 mpg with a 20 mpg" are the guys who are from the "math is too hard" club. For them going from 5 gp100m to 4 gp100m would be equally difficult to compare with going from 6 gp100m to 5 gp100m.

Besides why would they be doing that comparison? Are they thinking about which car to trade it in? Once again those are the guys who most likely don't have the ability to do any of that math in their head.

 

[Quattro Pete]

Vikas, you certainly have a point. If one is severely math challenged, none of this will work, regardless how you look at it.

I'm not advocating here that the whole US all of a sudden switch to gallons per 100 miles. I know it's not going to happen as it would be too much a paradigm shift for most to swallow.

Personally, I just find it useful as an extra value to help me visualize how much fuel would be used up/saved to travel 100 miles. When you look at 30 mpg vs 40 mpg, you might think, wow, that's impressive. But in reality, this means you'll only be using 0.83 gallons less for every 100 miles traveled. On the other hand, going from 10 mpg to 20 mpg means you'll be using 5 gallons less for every 100 miles traveled.

I think the main point these articles were trying to make is that a lot of people are preoccupied with getting/seeing that 1 extra mpg on the EPA sticker, but when mpg is already in the 30s, 40s, 50s, or 60s, that 1 extra mpg doesn't provide anywhere nearly as much benefit as when the mpg was in the 10s or 20s.

But yes, if you can do and understand the underlying math, it doesn't really matter what units of measure are used. And if you can't, then it's all useless anyway. I often see people being asked this question return a blank stare... "If you're traveling at the speed of 60 mph, how many miles would you have traveled in 1 hour?" People don't really understand what mph means, and I bet many don't understand what mpg means, just that the higher the number, the better.

 

[IndyIan]

I guess you could show Gal/100 miles on a bar graph and it would be easily understandable how much fuel each vehicle uses compared to each other.
MPG on a bar graph is a bit misleading if you are trying to compare fuel economy with a 5th grade understanding of math.

 

[RobertISaar]

not this again......

i'm going to generalize a bit, but the average person is only going to end up more confused if this were to change. they only know that they're supposed to put fuel in before the needle hits empty(if they're lucky, they have a low fuel lamp/chime/message to help them decide how low is too low) and that there is probably a way to get their car to show them their em pee gees so that they don't have to figure out a calculatin thingy.

trying to convince that person that a lower number will mean more distance traveled per gallon of fuel consumed will likely be futile.

i am personally a fan of "distance per volume", regardless of imperial/metric measurements, but i've had to convert back and forth enough times to form an opinion that it is much easier to use day to day. the mental math required to estimate the distance i can travel on the fuel i have remaining is far easier as-is, throwing in more steps along the way will lead to more rounding error.

 

[Clevy]

Originally Posted By: Vikas

As Click and Clack would say :---- Boooooogggggguuuuuuuusssss

The guys who think "replacing the 30 mpg with a 40 mpg one will be just as beneficial as replacing the 10 mpg with a 20 mpg" are the guys who are from the "math is too hard" club. For them going from 5 gp100m to 4 gp100m would be equally difficult to compare with going from 6 gp100m to 5 gp100m.

Besides why would they be doing that comparison? Are they thinking about which car to trade it in? Once again those are the guys who most likely don't have the ability to do any of that math in their head.




The math is too hard club

That is the funniest thing I've seen in a while. I almost spit coffee all over the cars dash.
Awesome

 

[Vikas]

Quote:
Personally, I just find it useful as an extra value to help me visualize how much fuel would be used up/saved to travel 100 miles. When you look at 30 mpg vs 40 mpg, you might think, wow, that's impressive. But in reality, this means you'll only be using 0.83 gallons less for every 100 miles traveled. On the other hand, going from 10 mpg to 20 mpg means you'll be using 5 gallons less for every 100 miles traveled.
Unfortunately, for the folks who can't do the percentages in their head this is pretty much like Greek and Latin to them. And those who can, the replacement units are unnecessary. I have no objection to adding another unit and in some cases, it will make it easier to do mental calculations for mathematically unchallenged subset. If you discount immigrants from the mix, that subset is going to be way smaller Besides, that subset is NOT driving the 10mpg vehicle in question as their DD. They are already driving 30mpg vehicle.

Bottomline:- People who can use it, they don't need it. People who need it, lack the ability to use it.

 

[Clevy]

I hate the litres per 100km carp they've got here. In fact I've got my charger set to English for 2 reasons. Psi for oil pressure and mpg on the readout.
Since I grew up with metric I'm semi clueless when it comes to Fahrenheit temps however I have gotten used to it and can function with it as far as knowing temps in F in the dashboard readout and converting to celcius.
I'm more comfortable with mpg however I'd be just as happy with kms per litre too. Based on the metric system at least everything is a multiple of 10 and simple decimal point movements.

 

[javacontour]

http://www.epa.gov/carlabel/gaslabelreadmore.htm

At least in the US they already show annual fuel costs based on estimates of average distance and cost. Anyone currently interested in the sort of analysis mentioned above can look at the projected annual fuel cost and compare.

So the g100 info is redundant as the annual fuel cost estimates were already on the label.

 

[Cujet]

Originally Posted By: Quattro Pete

The problem with MPG is that it is not linear and therefore it tends to cloud people's vision when trying to use fuel economy as a significant factor in new car shopping. In your example above, going from 10 mpg to 20 mpg is a much greater fuel economy benefit than going from 30 mpg to 40 mpg.



And, that is the crux of this argument. How to get people to clearly understand this point.

Again, I contend the average American is too stupid to understand 2.675 gallons per 100 miles. As the above formula contains a decimal or fraction. We now have a nation of idiots...

The average BITOG member is a generally sharp individual. Many here clearly and instinctively understand differential equations, not to mention simple math.

 

[Norm Olt]

Take a look at the car magazines expressing "CO2 EMMISSIONS" in x.xx lbs/m and "ENERGY CONS, CITY/HWY" in x.xx/x.xx kW-hrs/100 mi!

The "average" consumer already graduated from the "Math is TOO HARD Club" to the "What the HADES are they talking about Club?" about the third time they went through 6th Grade!

CHEERS!

p.s. Check out the "experts" at Motor Trend: in their Truck of the Year comparison test (Feb 2014) they used an entire page (pg. 60) detailing their extensive new sophisticated testing procedures... i.e. 0-60mph times UNLOADED & "LOADED"

They then promptly failed to list the PAYLOAD for the pickups that didn't win (YOU know, hint, hint: how much you can actually CARRY in the bed!), and then failed to list the load towed and results (?!?) for their TRUCK of the YEAR award winner, the RAM 1500 Diesel, showing ONLY "0-60, mph" as 8.9 sec. They did mention a factor of "75 percent of the as-tested towing capacity", which would allow one to extrapolate a load of 7,300 lbs. X 0.75 = 5,475 lbs., but what was the 0-60mph TIME when it was LOADED? What about BRAKING DISTANCES while towing that 75% "as-tested" towing capacity? UH, DUH!

p.p.s. The GMC SIERRA 1500 SLE (in V6 form, no less!) did a 7.4 sec 0-60mph & 17.3 sec with a 5,690 lb. trailer. I think a 1.5 second differential 0-60mph is impressive, especially for a truck that co$t almost $13K less at base price! They were not so impressed...

p.p.p.s. Nor was I impressed: these guys need an editor or a proofreader, or SOMETHING!

 

[accent2012]

What we really need on our cars is data pertaining to the following scenarios.

How much fuel is injected by the fuel injectors when you are accelerating along a flat road from 0-60mph; " " " " " " when you are acceleration along a minor-sloped hill from 0-60mph; " " " " " when you are cruising at 60mph for x distance; " " " " " " when you are accelerating from 0-30mph in less than 300 feet then stopping, and then repeating this cycle for a period of a mile(i.e. city driving).

 

[Vikas]

Get UltraGauge type of device and you have all the data. Unfortunately, it is still very hard to interpret it or monitor it. Even after driving a vehicle with all the information, I am still not able to tell you if I get best mileage at 65 or at 70.

 

[NHHEMI]

I think it is funny that some here believe if people think the gallons p/100 miles idea is foolish and will never catch on that somehow that is because those folks are too ignorant to understand how to figure it. Has nothing to do with MPG making more sense.

 

[Sonataman]

Originally Posted By: Vikas
Get UltraGauge type of device and you have all the data. Unfortunately, it is still very hard to interpret it or monitor it. Even after driving a vehicle with all the information, I am still not able to tell you if I get best mileage at 65 or at 70.


Been using one for 3 years and it's great.

In your own air, you should get better mileage at 65 than 70, but if 70 keeps you closer to the ave flow then you will benefit greatly from draft and corridor effect vs driving in your own air at 65.

I don't advocate drafting as being closer than your reaction time plus a second is risky in my book. The 2 second rule is there for a reason.