Product Definition/Scope - Top Ten USA lists the most environmentally-friendly cars and light trucks. Any car, pickup truck, van or SUV having a Gross Vehicle Weight Rating (GVWR) of less than 8,500 pounds is eligible. Motorcycle and vehicles that weigh more than 8,500 pounds GVWR are not considered.

Performance Criteria/Parameters Used – Vehicle rankings are based on Green Scores obtained from the American Council for an Energy-Efficiency Economy’s Green Book Online®. A vehicle’s Green Score is calculated from lifecycle emissions of greenhouse gases and traditional air pollutants as the vehicle moves from “cradle to grave”: materials production and product manufacturing; emissions and other effects when the vehicle is in use; through end-of-life effects of disposal and recycling. Each Green Score falls between 0 and 100. For a complete description of the methodology, see http://greenercars.org/greenbook_method.htm

Test Methods – Green Scores were generated from the results of the US Environmental Protection Agency’s fuel economy and emissions tests. Vehicle manufacturers provide to EPA “adjusted” (i.e. real-world) city and highway fuel economy estimates for all vehicles using a five-cycle test procedure outlined in EPA’s 2006 fuel economy labeling provisions (pp.77881-77892, EPA Fuel Economy Labeling of Motor Vehicles, 2006).  Likewise, each vehicle’s Tier 2 emissions certification, obtained via EPA’s emissions testing protocol, is an input to the Green Score.

Market Segmentation - We took the entire light-duty vehicle market and broke it down into two categories:
a.  Cars and 2-wheel-drive SUVs less than 6,000 lbs GVWR
b.  Pickup trucks, SUVs not included in the previous category, and vans

This breakdown reflects the classification NHTSA will use for fuel economy regulation purposes beginning with MY 2011 (pp.717, Average Fuel Economy Standards, Passenger Cars and Light Trucks, Model Year 2011).

Data Source – We used Green Scores obtained from the American Council for an Energy-Efficient Economy’s Green Book Online®.  Green Scores in turn were calculated from data (fuel economy, vehicle weight, tailpipe emissions certification) obtained from EPA.

Market Availability – In order to qualify for Top Ten USA, each vehicle model must be currently available across the country and must have a substantial anticipated sales volume. Additionally, consumers must have easy access to the necessary fuel and maintenance infrastructure for qualifying vehicles. As a result, we do not include compressed natural gas (CNG), as refueling stations are few and far between.

Families of Similar Products – To avoid multiple listings of the same product sold under different company badges, we combined these “twin” vehicles into a single entry. As an example; we created a single entry for the 2010 Ford Fusion Hybrid and the 2010 Mercury Milan Hybrid, which are built on the same platform by the same manufacturer but with different brand badges. Similarly, we allocated only one entry per nameplate on the Top Ten vehicle list. For instance, the Hyundai Tucson automatic and manual 4 wheel-drive trims both score similar Green Scores but we only included the automatic version in our Top Ten USA rankings.

Additional Information

ACEEE’s Green Book Online®: www.greenercars.org

Rating the Environmental Impact of Motor Vehicles - ACEEE’s Green Book® Methodology, 2004 Edition: http://www.aceee.org/store/proddetail.cfm?CFID=4765380&CFTOKEN=29089382&ItemID=382&CategoryID=7

Average Fuel Economy Standards, Passenger Cars and Light Trucks, Model Year 2011: http://www.nhtsa.gov/staticfiles/DOT/NHTSA/Rulemaking/Rules/Associated%20Files/CAFE_Updated_Final_Rule_MY2011.pdf

EPA Fuel Economy Labeling of Motor Vehicles: Revisions to Improve Calculation of Fuel Economy Estimates; Final Rule: http://www.epa.gov/fedrgstr/EPA-AIR/2006/December/Day-27/a9749.pdf