Gallons Per Mile

Let's assume two people drive 10,000 miles a year. If one of them has a 10 MPG gas guzzler and the other has a 20 MPG large sedan. The gas guzzler uses 1,000 gallons of gas per year and the large sedan uses 500 gallons. If both upgrade their cars and get cars that double their mileage. Who is saving more gas?

Didn't know you were coming to math class did you? That's OK. This is the kind of book that provides the answers.

The former driver of the gas guzzler is now getting 20MPG and will use 500 gallons of gasoline per year. His gasoline consumption has fallen 500 gallons per year (1,000 gal - 500 gal).

The former large sedan driver is now getting 40 MPG and will use 250 gallons per year. His gasoline consumption has fallen 250 gallons per year (500 gal - 250 gal).

The former gas guzzler driver is saving twice as much gasoline as the former large sedan driver. What this measures is the gallons used over a given distance. At $4/gallon the former gas guzzler driver is saving $2000.00/ year. When my brother recently traded his cars we went through this calculation to determine how much money he and his wife were going to save.

The point is that incremental increases from very low mileage to moderate mileage is much better than larger increases when someone is already getting reasonable mileage.

Now obviously, it would be best if both drivers upgraded to a 40MPG car. But if you are a person that has a real need (not being cool) for a large vehicle, it can be hugely beneficial to upgrade to a vehicle that gets slightly better mileage.