Now wait, are you saying that the driving data from the various cars is from different years... and thus different weather conditions? I thought in your earlier comment you merely meant the study showed different model years for some of the cars. But yeah, if the data isn't even from the same years, and considering the record-setting cold temperatures seen in much of the U.S. recently, then I agree this study is useless. I don't think we should necessarily demand that every single study conform to the highest standards of scientific skepticism (which would involve a double-blind study), nor should we necessarily insist on statistically valid sample sizes -- which would require hundreds of units of each model of car, not just one. But if they aren't even comparing time periods with the same weather conditions, then indeed any comparison isn't worth inconveniencing so many electrons.