The EPA are busy redesigning the familiar window labels that American buyers are used to seeing in car windows. They're trying to come to terms with how best to represent newer hybrids and all-electric vehicles. The simplest proposal has a slight label redesign, but essentially remains much like the labels available today. The larger redesign involves adding a prominent colour-coded grade to the vehicle, ranging from A to D, to give you a one-shot indicator as to how good or bad the vehicle is in terms of fuel economy. The US auto manufacturers aren't too keen on this last idea - probably because a lot of the vehicles would end up in the "D" category, but there's a way to go yet. If you want to get involved, the EPA have a website where you can see the new sticker designs and comment on them if you like:
New EPA fuel economy labels