For the 8th year, the Honda Civic GX earned the top ranking in the annual environmental rankings produced by the American Council for an Energy-Efficient Economy (ACEEE) at greenercars.org.
Despite changes to the Green Book® rating methods that boosted other technologies, the natural gas powered vehicle still came out on top.
But the lineup of the remaining dozen top cars proved an interesting blend of plug-ins, gasoline hybrids, and ever-improving "conventional" gasoline vehicles.
The all-electric Nissan Leaf places second, followed by the gasoline-powered Smart Fortwo. Hybrids take the next three spots, followed closely by Ford's new Fiesta SFE (Super Fuel Economy) and the Chevrolet Cruze Eco.
Also notable on this year's list is the Hyundai Elantra, with a 4 mile-per-gallon jump in fuel economy over the 2010 model. Rounding out the "Greenest" list is the much-touted Chevrolet Volt "extended-range EV," which slips into the 12th spot. All told, five new models pushed out entries on last year's list.
The strong showing of conventional vehicles in the top twelve is a testament to how serious manufacturers have gotten about recasting these vehicles as fuel-sippers with transmission refinements, weight savings, and sophisticated internal combustion engines. "We're seeing an increasing number of highly efficient gasoline options from both foreign and domestic automakers along with the first electric vehicles. Ford introduced the Fiesta this year and Chevrolet debuted the Cruze, both of which do exceedingly well in our ratings," said ACEEE vehicle analyst Shruti Vaidyanathan.
Regarding plug-in vehicles, ACEEE Transportation Director Therese Langer noted: "Vehicles running on electricity emit nothing from the tailpipe, but their 'upstream' emissions can be substantial, depending on where they're charged. As U.S. power generation becomes cleaner, these vehicles' scores will rise."
The Green Book® methodology update also incorporates emissions associated with battery manufacture and disposal in a manner that reflects material content, drawing from Argonne National Lab's GREET model. Hybrids lose a couple of points on their Green Scores as a result and this year capture only three of the top 12 spots. Once again diesels fall just short of the Greenest list.
The "Meanest" list this year is populated largely by heavy trucks and SUVs, a marked change from the numerous European sports cars that dominated last year's list. Nevertheless, the Bugatti Veyron tops the list this year with a Green Score of 19.