A suggestion: right now, Fuelly is using the MPG and L/100km as the basic units of measurements for fuel economy. But the truth is, fuel economy isn't primarily about the type of vehicle being driven, it's about driving smart.
A driver with a 20 MPG car who commutes 20 miles per day round trip burns only one gallon of gas. A driver with a 40 MPG car who goes 80 miles round trip in her commute burns 2 gallons. People who drive long distances inevitably look better than people with short commutes that overall burn less gas, but have a lower MPG ratio.
I suggest that Fuelly emphasize this point by including the total number of gallons burned, along with the avg. gallons burned per day on the Fuelly Badge. After all, the best way to save fuel is to burn less of it, not to hit an arbitrary MPG figure.
in regard to lowering fuel consumption, the type of vehicle can be just as important as driving technique. why commute alone in a large vehicle? but, if that vehicle serves other purposes as well, it may be a good choice. insuring 2 vehicles may or may be a good financial decision.
there are too many variables to make a real comparison between drivers. some drivers may be able to bike or use mass transit to limit their consumption. the fuel savings there would be most difficult to track. others may want to live away from the city to raise a family.
your thought does hold merit however. the bottom line is many of us can improve our efficiency by owning a smaller vehicle and driving less. that's not a political position. i drive a commercial vehicle, so i truly realize that large vehicles and trucks are necessary.
While I have no problem with seeing my total number of gallons used and average number of gallons per day posted for all to see, I do take issue with your statement that I "...look better than people with short commutes that overall burn less gas..." As bowtieguy points out, I work in the city, but wouldn't consider living there. I accept my 45 mile each way commute in exchange for quality of life for myself, my wife, and my kids. The cost is significant when you consider that commuting takes at least 2 and a half hours out of my life every day not to mention the wear and tear on my commuting car in the form of gasoline, tires, brakes, routine maintenance, and repairs, but for me LA is no place to live so I make that commute to work. I try to be responsible about my choice to live as far away from work as I do, and I've chosen for my last 2 vehicles to buy cars that get pretty good mileage in spite of the fact that my current car won't fit my whole family in it at one time. This is both ecologically responsible and self serving (when gas was nearly $5.00 a gallon last June / July it hurt bad enough with a 30 MPG car, it would have been a lot worse in the 20 MPG car and SUV that I really wanted to buy).
Essentially, my issue is with your attitude that a short relatively high consumption commute is better than a long relatively low commute. I disagree with your argument, but not your goal if you get what I mean.
For the record, I have lived in the same neighborhood for 3 years longer than I have been at my current job, although I was working another job at LAX when I bought my previous home. Unfortunately for me, I'm in a career specialty that requires that I work at a major airport so I can't just find another job closer to work. Further, LAX is surrounded on 3 sides by parts of town that are not very safe and by water on the 4 th side so I can not really find another method of commuting to lessen my miles driven. I'd love to be able to ride my bike to work some times, but I can't get through the bad parts of town without a car.