They're the cleanest vehicles on the road according to the American Council for an Energy Efficient Economy.
Not everyone can drive a compact car, though, so the group supplied us with a list of the greenest cars in 14 different categories from subcompacts to full-size pick-ups.
The ACEEE bases its "Greenest" and "Meanest" vehicle selections mainly on fuel economy, but other factors figure in, including the amount of noxious emissions it puts out and pollution created in the manufacturing process, which is estimated based on a vehicles' weight.
The category designations are ACEEE's and are based, in some cases, on EPA vehicle size classifications. In other cases, the ACEEE created its own classifications.
Scores ran as high as 57 and as low as 16.
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