The criteria for a SmartWay certified vehicle is based on the vehicle emission scores that can be found on the U.S. EPA's Green Vehicle Guide (www.epa.gov/greenvehicles). The vehicle emission scores include the Greenhouse Gas Score and the Air Pollution Score.

The Air Pollution Score is based on the vehicle's officially certified exhaust emission standard as indicated on its Certificate of Conformity. In simpler terms, the less a vehicle contributes to smog, haze, poor health conditions and general air pollution, the higher the score will be.

The Greenhouse Gas Score for SmartWay certified cars is based on the combined adjusted fuel economy label value determined according to the Code of Federal Regulations, based on vehicle fuel type. Thus a higher score means that the vehicle has a higher fuel economy and emits less greenhouse-gas-causing emissions.

The SmartWay certification mark is achieved if a vehicle receives a minimum of 6 out of 10 on both the Greenhouse Gas Score and the Air Pollution Score, AND receives a combined score of 13 or higher.