Fuel Efficiency: A More Practical Perspective

It is undeniable, from a historical perspective, that there was a shift in emphasis in motor vehicle development and marketing from the seventies and eighties, when fuel efficiency was a major consideration, to the nineties and naughties, when fuel efficiency has mostly not been a major consideration. Now there are people who want to shift things back in the other direction, but... not everyone is buying it.

One thing I've noticed is that it seems like everyone talking about vehicle fuel efficiency these days is talking about the environment. While there's nothing per se wrong with that, it's not an effective motivator for most people. For one thing, it's very hard to quantify. If John buys a vehicle that uses 25% less fuel, how much impact can he expect that to have on the environment, anyway?

So I'd like to look at it from a more immediately practical and quantifiable perspective: the pocketbook. This is something almost everyone should be able to relate to. If John buys a vehicle that uses 25% less fuel, how much money will he save on gas, over the life of the vehicle? How much per year?

It depends on usage patterns, of course, but let's construct a hypothetical example. Let's say there are two models of vehicle, the Strontium and the Rubidium. Of course in practice there are way more than two models of vehicle available, but comparing only two makes the example simpler. So the Strontium gets almost 22 miles to the gallon (average, for the type of driving John does, blah, blah, blah) and the Rubidium gets a little over 29 mpg (with the same qualifications), i.e., it uses 25% less fuel to go the same distance. There are, of course, other differences between the vehicles, e.g., the Strontium is probably a little larger. But for now let's just figure how much difference it's going to make in gas costs.

If John is typical, he probably drives to work and back about five days a week, plus some assorted other driving. You can plug in figures that fit your situation more closely, but for the example we'll say he drives thirty minutes to work, averaging (with stop lights and everything) about 27 mph, which is typical for driving with only light traffic, only partly in town. During the 30 minute commute each way, then, he covers 13.5 miles, for a total of 135 miles a week just driving to and from work. Toss in another couple of hours of assorted other driving here and there (to church, to the mall, to the video store, to grandma's house, wherever) and you're looking at closer to 200 miles a week of driving. Again, you can plug in your own numbers and get something more relevant to your own situation.

200 miles a week means the Strontium will use about 9 gallons of gas, and the Rubidium will use about 6.8 gallons, in a week. At $4 per gallon (obviously, the price may fluctuate...) that means the Strontium costs John about $36/week to drive, and the Rubidium costs about $27.20/week, a difference of about $8.80 per week, or $460/year. If John intends to drive this vehicle for ten years, the more fuel-efficient vehicle is the better deal, from a purely financial perspective, unless it costs at least $4600 more (all else being equal).

You can plug in the numbers for actual vehicles at your leisure. Note, however, that for hybrid vehicles you have to factor in the cost of electricity you expend charging them, in addition to the gasoline (or diesel or alcohol or whatever).