What are Green Scores?

Vehicles are grouped together by class (that is, the type or body style, such as midsize car, minivan, standard pickup, and so on). To make it easy to find the top-rated vehicles in each class, ACEEE's Green Book® uses a five-tier class ranking—Superior, Above Average, Average, Below Average, and Inferior—depending on where a model falls within its class. No vehicle gets a Superior rating if its Green Score is worse than the overall average of all vehicles offered this model year, even if it ranks among the best in its class. Buyers should look for models that are ranked Superior or Above Average to easily find those that have the greenest scores.

The green score comes with each vehicle's emission standard, fuel economy, fuel costs, health effects, CO2 emissions, and overall environmental impact, along with its Green Score and Class Ranking. The pollution coming from a vehicle depends on the standard it meets, how well its emissions controls work, how it is driven and maintained, its fuel consumption, and its fuel quality. Vans, pickup trucks, and sport utilities are classified by the government as light trucks, and as such have less stringent fuel economy standards than passenger cars. As a result, the average light truck pollutes more than the average car.

Check out the Green Scores:

The Greenest Cars of 2009 lists the top models having the highest Green Scores overall.

The Worst Cars for the Environment in 2009 lists the 20 cars and trucks with the worst Green Scores.

For earlier model years, fuel economy was an important determinant of greenness. So look for high-efficiency models on the Federal Fuel Economy Guide Web site.