Imagine, if you will, taking a sheet of paper and cutting it in half. Now take one of those halves and cut it in half again. Now keep repeating the process. As you keep cutting, the difference in the size of the subsequent pieces gets progressively smaller. This simple example is a demonstration of why continuing to increase the fuel mileage of a vehicle has less and less impact once you get beyond about 35-40 mpg.
Gallons Per Mile
Back in June, we took a look at the distinction between miles per gallon (MPG) and gallons per mile (GPM). At first blush, it may seem this is a six of one, half-dozen of another situation. It's not. MPG is the most common number cited when people want to understand how efficient a car is, especially in the US. Richard Larrick, Associate Professor of Management and Organizations at Duke University, says that the MPG number is wholly inadequate to understand the way that car models get cleaner th