AFAIK, MPG is not used anywhere in the world but in one country where people don't even grasp the beginning of it.
MPG is actually quite useless to do range estimates. If you got n gallons you could possibly maybe travel more or less m miles depending on a variety of factors unrelated to the vehicle fuel efficiency such as speed, terrain, open or closed windows, driving with A/C on, and much more.
There are a few mythbusters episodes dedicated to the myths of fuel efficiency/consumption.
GPM doesn't seem that useful for budget estimates either as this depends on the fuel price, well maybe it is in the US where oil price is maintained artificially low but in other parts of the world you have a hard time guessing the price of oil 6 months from now or at the next gas station.
I've seen price fluctuation of 0.8$ per gallon from a week to the next and 1.5$ per gallon from a gas station to the next in the same city.
GPM is only useful to compare vehicles between them, which is something people in position of power in the USA do not want.
If you got n gallons you could possibly maybe travel more or less m miles
I track my mileage in a hardcopy log: miles driven, fuel consumed, and mileage.
While I see some variation (about 35% difference between worst urban and best highway driving), I've got a very solid idea of how much range I can get on a tank under various driving conditions. Sufficient to make "stop or continue" decisions when passing fuel stops on long road trips (though sometimes cutting that closer than I'd prefer).
MPG is actually quite useless to do range estimates. If you got n gallons you could possibly maybe travel more or less m miles depending on a variety of factors unrelated to the vehicle fuel efficiency such as speed, terrain, open or closed windows, driving with A/C on, and much more. There are a few mythbusters episodes dedicated to the myths of fuel efficiency/consumption.
GPM doesn't seem that useful for budget estimates either as this depends on the fuel price, well maybe it is in the US where oil price is maintained artificially low but in other parts of the world you have a hard time guessing the price of oil 6 months from now or at the next gas station. I've seen price fluctuation of 0.8$ per gallon from a week to the next and 1.5$ per gallon from a gas station to the next in the same city. GPM is only useful to compare vehicles between them, which is something people in position of power in the USA do not want.