This should be relatively straightforward, since there can’t be much argument about the hybrids with the best EPA ratings. It’s all in the numbers and based on the Environmental Protection Agency’s carefully defined testing procedures. Those, for the curious, include standardized evaluations for traditional city and highway driving, along with specific tests designed to replicate real-world scenarios involving higher driving speeds, increased air-conditioning use and colder ambient temperatures. But they’re still laboratory-based, and the EPA still reminds drivers that their actual mileage will vary. And it also still adds up to another win for a long-time fuel-efficiency champ.