The American Council for an Energy Efficient Economy and it's consumer organization, GreenerCars.com, have released their 2006 Green Book, giving consumers truly useful information about the environmental impact of cars they may be thinking about buying. Unlike other rankings, which value innovation and an American design, the Green Book focuses solely on emissions and fossil fuel use, giving each car a green score that buyers can easily rank. It's not surprising that the top five is completely dominated by Honda and Toyota, and that four of the five are either hybrid gas-electric cars or powered by natural gas. The closest an American car came was eleventh place (the Chevy Cobalt), but you can get a little extra cargo room with the Toyota Matrix and still be in the top ten.

The Green Book also lists the top ten meanest cars--cars with the lowest combined fuel economy and emissions ratings. Cars designed for racing (Lamborgini's Murcielago) and heavy-duty trucks (Ford's F250) dominate the list. I was surprised that the Hummer H2 was only number 7, but not surprised that three of the top five, including the #1 meanest car in America, were Dodges.

With a paid subscription to the Green Book, consumers looking beyond small sedans and heavy duty trucks can see the list by vehicle class. If you have four kids, you might not be shopping on the Honda Insight/Toyota Prius aisle, but the Green Book will help you pick a minivan or full-size SUV. [Source: GreenerCars.com]