The Concept of Fuel Economy: Does it Lead to Good Decisions?

July 1, 2008 · Filed Under Retail & Spot Prices, Transportation 

If you own two vehicles, a car and a SUV about the same age, then you will inevitably be faced with the decision of which car to replace first. If saving fuel is one of your motives, then you might be interested in this quick miles-per-gallon-math from Technology Review.

Say you’ve got two cars in your garage. One of them gets 34 miles per gallon; the other gets only 12. You drive both cars 10,000 miles in the course of a year.

Would you save more gas by a) trading in the 34-miles-per-gallon car for one that gets 50 miles per gallon, or by b) trading in the 12-miles-per-gallon car for one that gets 14 miles per gallon?

New experiments suggest that people tend to pick a). After all, a 16-miles-per-gallon improvement seems better than an improvement of just 2 miles per gallon.

The right answer is b).

If you start driving the 50-miles-per-gallon car instead of the 34-miles-per-gallon car, you’ll save 94.1 gallons of gas per year.

If you start driving the 14-miles-per-gallon car instead of the 12-miles-per-gallon car, you’ll save 119 gallons per year.

The math is simple arithmetic. Divide the total number of miles driven (10,000) by the miles per gallon to get the total gallons used to drive that distance. For 12 miles per gallon, the answer is 833. For 14 miles per gallon, it’s 714.

So what do you think — is “mpg” a good indicator of fuel economy?

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Comments

2 Responses to “The Concept of Fuel Economy: Does it Lead to Good Decisions?”

  1. Josh Maxwell on July 1st, 2008 1:59 pm

    I just stopped by your blog and thought I would say hello. I like your site design. Looking forward to reading more down the road.

  2. Fuel consumption vs. miles per gallon : Energy Analysis on January 19th, 2009 4:29 pm

    [...] Energy Analysis: The Concept of Fuel Economy: Does it Lead to Good Decisions? [...]

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