An interesting thought about fuel economy...

I was talking with a co-working today about fuel economy and he illustrated to me how our way of looking at fuel efficiency is fundamentally flawed. We get excited when something like a Prius hybrid car gets 45 mpg. I have a Civic which is comparably sized to the Prius and it gets in the neighborhood of 35 mpg. So, the Prius, which carries a hefty fiscal penalty up front, will get me a little better mileage over the long run. However, my Civic really doesn't burn all that much gas based on how much I drive, so any increase in efficiency wouldn't really save me all that much money.

The true measure of efficiency should be consumption. Think of this:

2 pairs of cars.
The first pair of cars consists of a car that gets 12 mpg, and one that gets 500 mpg.

The second pair of cars consists of a car that gets 16 mpg, and one that gets 50 mpg.

When asked, most people would say that the first pair is more efficient. After all, the one car get 10 times the mpg of the other. However, when you do the math, the results aren't intuitive.

When each car is asked to drive 500 miles, they burn the following amount of fuel:

First Pair:
500 miles @ 12 mpg = 41.6 gallons
500 miles @ 500 mpg = 1 gallon
Total Consumption = 42.6 gallons of fuel

Second pair:
500 miles at 16 mpg = 31.25 gallons
500 miles at 50 mpg = 10 gallons
Total Consumption = 41.25 gallons

As illustrated by this example, maybe GM's strategy of improving the efficiency of their big burners like the new hybrid Tahoe is superior to Toyota wringing a tiny bit more efficiency out of its already miserly subcompacts.