Improvements in Fuel Economy for Low-MPG Vehicles Yield the Greatest Savings

The relationship between gallons used over a given distance and miles per gallon (mpg) is not linear. Trading a low-mpg car or truck for one with just slightly better mpg will save more fuel than trading a high-mpg car or truck for one that is even higher. An improvement in fuel economy by 5 mpg does not translate to a constant fuel savings amount. For example, trading a truck that gets 10 mpg for a new one that gets 15 mpg will save 33 gallons of fuel for every 1,000 miles driven. In contrast, trading a 30-mpg car for a new car that gets 35 mpg will save 5 gallons of fuel for every 1,000 miles driven.