Buying a car is just about my least favorite activity.  The salesmen are pushy, you always have to watch for hidden fees, and honestly, there are almost too many cars for me to choose from. I narrow down my selection by car style, number of doors, manufacturer, and price point, then I’m left to consider the exact model, what color, whether it has a sun roof, and what kind of gas mileage it gets.

By the end of the day, I’m usually exhausted by the sheer act of holding all of that comparative data in my brain.  And then the negotiation begins…

Well, the EPA is hoping to make the environmental impact of car shopping a little easier to discern by posting letter grades and other data right on the window.  They’re considering two designs, and they’re open to comments (click the image for an interactive explanation of the various metrics):

You can see in this first example, they give the car a letter grade and tell you how much you might save over the average car right near the top, suggesting that they’ve paid attention to the best practices of graphic design. Below that, they’ve got a series of metrics including the city and highway MPG, and the fuel consumption given in gallons/100 miles.  I’m not sure what this adds to the discussion, as it is simply 100 miles divided by the 26 combined mpg, but they seem to think it’s a big deal.  In the explanation, they state:

4. This vehicle uses 3.8 gallons of gasoline to travel 100 miles for combined city and highway driving. This is an energy efficiency rate called fuel consumption. Fuel consumption values, unlike MPG, relate directly to the amount of fuel used.

Um.  Okay.  If you insist.  I mean, am I missing something really valuable here that could not be determined by looking at the MPG?  Is there a situation in which MPG would mistakenly lead you to believe a car is more efficient than it really is?

Underneath that, there are a few tiny sliders showing the car’s relative MPG, carbon emissions, and other air pollutants.  No real surprises here, since a car’s carbon emissions are more or less directly proportional to the amount of gas it burns.  There’s certainly more variation in the air pollutants based on control technologies and how the car is running, but one gallon of gas has the same number of combustible carbon molecules as another gallon.

Finally, the label shows the MPG range for other cars in its class in some mice-type at the bottom.  Here is where the second label shines by comparison:

Take a look at bubble 3 (“How This Vehicle Compares”).  They add a little bracket below the slider showing where SUVs fall on the scale.  Simple, but much more effective than the text version.  Now I know that the car is below average compared with all cars and light trucks, but it’s actually one of the better SUVs, and if that’s what I’m buying, I may want the best one.  Or, the least worst, as it were.

Do you like it?  Would you use it in making your next purchase?