Mom's Minivan: Don't postpone increased fuel-efficiency

As Google announces efforts to develop a 100-mpg car, we should all remember to do what we can to be fuel efficient in the meantime. Increasing fuel efficiency of low-mileage cars can save even more gas.

When I was in graduate school I learned the important life lesson "don't postpone joy." Not that graduate school could ever be considered fun, but at one point I was so miserable that I realized that I couldn't count on riding out the two to three years until graduation to start living my life with enjoyment and happiness.

That memory came to mind when I read about Google's research effort to develop a plug-in hybrid electric car that gets 70 to 100 miles per gallon. What if you are in the market right now for a minivan or SUV--should you sweat the difference between 18 and 22 mpg? The answer is a resounding YES. The biggest gains in fuel savings can actually be made by tweaking the efficiency of the worst gas-guzzlers. Innovation experts Barry Nalebuff and Ian Ayers explain why.

I heard Barry Nalebuff speak on this topic last January when he taught from his book Why Not? How to Use Everyday Ingenuity to Solve Problems Big and Small. His work encourages us to turn problems upside-down to generate new solutions. By flipping our concept of "miles per gallon" to "gallons used per 1000 miles" we can more easily compare the fuel efficiency of two car models. Nalebuff and his co-author Ian Ayres explain this example in their article Easy Savings:

"Imagine that Sybil owns a Toyota Prius and a Cadillac Escalade and that she drives each 10,000 miles a year. Suppose she could somehow increase the energy efficiency of her Prius from 50 to 60 mpg or increase the fuel efficiency of her Escalade from 15 to 16.5 mpg. Which should she choose? The Prius, right? The miles-per-gallon increase is 20% for the Prius versus 10% for the Escalade; the raw increase (10 mpg versus 1.5 mpg) is also greater for the Prius.

Wrong. Increasing the Prius' fuel efficiency from 50 mpg to 60 mpg saves only 33 gallons of gas a year. Increasing the Escalade's efficiency from 15 to 16.5 mpg saves almost twice as much: 61 gallons a year.

Looking at gallons per 1,000 miles makes the comparison easy. The Escalade's fuel usage went from 66.6 to 60.6 gallons per kilomile, while the Prius' consumption fell from 20 to 16.6 gallons per kilomile. Saving 6 gallons beats saving 3.3.

We need to focus on fuel efficiency at the bottom of the range, not the top. The miles-per-gallon statistic focuses our attention on the wrong end of the distribution. Instead of looking for 100 mpg wonders, we need to spend more time coaxing slightly better fuel efficiencies out of gas-guzzlers, especially high-mileage ones, such as taxis."

So while we contemplate the marvels of cutting-edge hybrid technology, don't let that stop us from making the improvements we can in the here and now. If you can't afford the extra cost of a Prius, or need to drive a minivan full of kids, remember that choosing the most fuel-efficient vehicle you possibly can is always a worthy goal.