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How SmartWay Vehicles Work


SmartWay Vehicles and EPA Certification
The EPA combines two ratings, the air pollution and greenhouse gas scores, to determine whether or not a vehicle is SmartWay-certified.­
The EPA combines two ratings, the air pollution and greenhouse gas scores, to determine whether or not a vehicle is SmartWay-certified.­
David McNew/Getty Images

Periodically, the EPA releases a Green Vehicle Guide that scores cars and trucks on how environmentally friendly they are. It's simply a useful resource for people looking for fuel-efficient vehicles, and you can look up nearly any recent car on the EPA Web site.

Every vehicle the EPA looks at, whether it's a car, an SUV or a truck, gets two different scores, an air pollution score and a greenhouse gas score. Respectively, these scores rate emission levels and fuel economy values.

The air pollution score rates the emissions coming out of a vehicle's tailpipe. This keeps track of the levels of harmful pollutants that vehicles release into the air. If you've ever had your vehicle's emissions tested, this is just about the same thing -- a monitor is placed inside your vehicle's tailpipe, and while the tester runs the engine, the tailpipe emissions are captured and measured. Before any car goes on the market, a sample vehicle has to go through these tests, and the EPA keeps a record of the numbers.

The greenhouse gas score, on the other hand, reflects specifically the amount of carbon dioxide (CO2) and the two other greenhouse gases that come from the test vehicles -- nitrous oxide (N2O) and methane (CH4). The greenhouse gas score is based on a vehicle's fuel economy, or how efficiently an engine burns fuel. The less fuel a vehicle burns over a long period of time, the less CO2, N2O and CH4 gets into the atmosphere. So the better a vehicle's fuel efficiency, the higher its score will be.

Both of these scores range from 0 to 10, where 0 is downright terrible and 10 is the best. So, how does a vehicle get the SmartWay certification? The EPA adds the air pollution and greenhouse gas scores together. To get the SmartWay stamp of approval, both scores must be at least 6. So if your vehicle has an air pollution score of 7, but a greenhouse gas score of only 5, you're out of luck. But there's another a catch -- the scores have to add up to at least 13. So again, if both of a vehicle's scores are 6 and add up to 12, the vehicle doesn't make the cut. A 6 on one score and a 7 on another is the very least a vehicle can receive before getting SmartWay certification next to its listing in the EPA's Green Vehicle Guide -- an online database for anyone interested in their eco-friendly driving options.

But is there an even higher distinction than SmartWay certification?


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