Photo credit: Flickr/Autoviva.

We can tell a lot about a person based on what kind of car he or she drives. If someone rolls by in a minivan, we safely assume that family is important to that person. Meanwhile, the bright red sports car that just zoomed past typically suggests its owner is a risk taker and maybe even a bit showy. On the other hand, seeing a Toyota (NYSE:TM) Prius C motor by says just one thing about the driver. That person has gone green. 

The carbon dilemma
Being green is pretty hip these days. It's a title that brings with it an air of sophistication. It suggests the person is more aware of the direct impact he or she has on the environment. However, it's a title one cannot easily obtain without driving a green car. 

Each gallon of gasoline we burn typically spews 20 pounds of carbon dioxide into the atmosphere. That's roughly 5 to 9 tons of carbon dioxide each year for a typical vehicle. On the other hand, a switch to a more fuel-efficient vehicle can really slash those emissions. 

Take, for example, a gas guzzler that gets 15 miles per gallon. It will unleash 11.7 tons of carbon dioxide each year. On the other hand, a fuel sipper that gets 45 miles per gallon will release only 3.9 tons of carbon dioxide each year. That's a big difference.

The difference is almost as large when looking at the average new car. According to the EPA, the average new car sold last year achieved only about 23 MPG. There is a compelling case to be made that being average isn't good enough. That's especially true when considering that owning a green car can mean its owner has slashed the carbon footprint of his or her vehicle nearly in half. 

So you call yourself green
So if somebody wants to be considered "green," that person really should drive one of the greenest cars on the market. Leaving out electric vehicles and plug-in hybrids, here's the current list of the top 10 most fuel-efficient cars in America, rated by a combination of affordability and fuel economy. 

  • Toyota Prius C: 50 MPG combined
  • Toyota Prius: 50 MPG combined
  • Toyota Camry Hybrid: 41 MPG combined
  • Honda (NYSE:HMC) Insight Hybrid: 42 MPG combined
  • Lexus CT 200h: 42 MPG combined
  • Honda Civic Hybrid: 44 MPG combined
  • Ford (NYSE:F) C-Max Hybrid: 47 MPG combined
  • Toyota Prius V: 42 MPG combined
  • Volkswagen Jetta Hybrid: 45 MPG combined
  • Lincoln MKZ Hybrid: 45 MPG combined

Toyota clearly dominates that list, as its holds half of the top 10 spots if we include Lexus. Meanwhile, Honda and Ford both claim two spots. All three automakers have made headlines for making affordable green cars, so it's no surprise to see this list dominated by those three automakers. 

Final thoughts
A recent study found that if all Americans were to drive green cars in the future, we could slash our greenhouse emissions from driving by 80% by 2050. That could lead to a more than 10% overall reduction in U.S emissions, as consumer-driven autos currently represent 17% of the nation's emissions. So the next time someone claims to have "gone green," make sure the car that person drives backs up the claim.