How SmartWay Vehicles Work

The EPA has developed a handy guide that identifies SmartWay vehicles, a set of cars, SUVs and pickup trucks that have above-average fuel economy.
The EPA has developed a handy guide that identifies SmartWay vehicles, a set of cars, SUVs and pickup trucks that have above-average fuel economy.
Jonathan Fickies/Getty Images


Just imagine for a moment that you didn't have a car, but you still had to get to the places that are important in your daily life. You could take public transportation, like the bus or the subway, but it's not always convenient to take the bus or train. Carpooling is an option, but sometimes can be difficult to organize, especially if you don't know anyone. You might have to travel miles just to get to work or school. Without a car, you might be stuck.


Of course, some people simply don't own a car, and others have the fortune of being able to use public transportation, live close to work or even work from home. But because most people live complex, fast-paced modern lifestyles, it's difficult for them to get around without a vehicle. Whether it's career-related activities like work and school or everyday things like shopping and other errands, cars, SUVs and pickup trucks help us get from point A to point B with relative ease.

­On one hand, cars are convenient for us -- they carry our belongings, groceries and, most importantly, people. But most realize that automobiles create harmful pollution that contributes significantly to global warming. The byproduct of burning fuel in an internal combustion engine is the emissions that come out of your vehicle's tailpipe -- greenhouse gases that get trapped in the Earth's atmosphere cause global temperatures to rise.

There are a number of initiatives you can take to reduce automobile emissions. For one, you can try the above-mentioned methods, like public transportation or carpooling, to reduce your carbon footprint. And even changing the way you drive and learning green driving habits, like obeying speed limits and avoiding rapid acceleration and braking, will lower your emissions and increase your vehicle's fuel efficiency.

And thanks to the Environmental Protection Agency (EPA), if you're thinking about buying a new car with the intent of doing a little eco-friendly driving, you can start even earlier by buying smart. The organization has developed a certification system, called SmartWay, to help future green-minded car owners easily identify vehicles that pollute less and have better fuel economy. The better environmental performer a car is, the more chance it has of getting recognized by the EPA. So how does SmartWay certification 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?


SmartWay Vehicles vs. SmartWay Elite Vehicles


So, vehicles that have SmartWay certification are not only fuel-efficient vehicles, but also great cars and trucks to buy if you're concerned about emissions and want to have less of a negative impact on the environment. According to the EPA's estimates, they're better than your average gas guzzler. But what about the cream of the crop? The greenest of the green driving machines? A green so bright your eyes may become temporarily blinded?


The EPA goes a step further and has created an extra classification on top of the SmartWay certification -- a category called SmartWay Elite. Any car, truck or SUV that gets the SmartWay Elite stamp of approval by the EPA is deemed a "superior environmental performer." To understand the importance of the distinction, a SmartWay certified vehicle, in comparison, is considered a "good environmental performer," according to the EPA.

SmartWay Elite vehicles are judged the same way all other vehicles are judged. But to be considered SmartWay Elite, the vehicle has to receive a score of 9 or better on both the greenhouse gas and air pollution scores. When the highest combined score possible for any vehicle is 20, and the lowest score necessary for Elite distinction is 18, you can be sure that SmartWay Elite certification isn't handed out to just any car with four wheels and a fuel-efficient engine.

So far, only a select few hybrids and compressed natural gas (CNG) vehicles have qualified for SmartWay Elite status. But there are several SmartWay vehicle choices available, especially in states like California, Massachusetts, Maine, New York and Vermont. This is because these five states adhere to the California Air Resources Board (CARB) tailpipe emissions standards, which sets tougher emissions standards for manufacturers [source:].

For lots more information on cars, eco-friendly driving and the environment, it'd be a smart move to see the links on the next page.


Lots More Information

Related HowStuffWorks Articles

  • Edmunds, Dan. "SmartWay: The EPA's Green Vehicle Ratings Program." May 1, 2007. (March 22, 2009)
  • United States Environmental Protection Agency. "Green Vehicle Guide: About the Ratings." March 26, 2009. (March 26, 2009)
  • United States Environmental Protection Agency. "SmartWay Certified." Dec. 12, 2008. (March 22, 2009)