The EPA is working on new fuel economy window stickers for cars (you can vote on alternatives). I like this one:
hoisted from the comments at jalopnik
There are some things to like about the possible new version. For example, it indicates fuel economy on an absolute scale, so that there’s no implicit allocation of pollution rights to bigger vehicles (unlike Energy Star and the CAFE standard):
Since the new stickers will indicate fueling costs, emissions taxes on fuels will be a nice complementary policy, as they’ll be more evident on the dealer lot.