In Europe fuel consumption of automobiles is measured in litres/100 km.
Litres are a measure of VOLUME; Kilometers are a measure of length.
Therefore, litres/100 km is a measure of AREA.
In the US fuel consumption of vehicles is measured in miles/gallon.
Gallons are a measure of VOLUME; Miles are a measure of length.
Therefore, miles/gallon is a measure of 1/AREA.
What is the significance of this AREA?