Green cars can't help reduce emissions or save gasoline if no one buys them.

In the U.S., sales of electric cars and plug-in hybrids have been strong in some areas, but weak in others--and it may be because dealers are emphasizing green too much.

Lincoln Merrihew--vice president, transportation for market-research firm MillwardBrown Digital--told WardsAuto that buyers are unlikely to choose a car just because it's green.

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He called green a "feel-good strategy," and instead advised dealers to emphasize the potential cost savings that come with a more-efficient vehicle.

2014 Nissan Leaf

2014 Nissan Leaf

For car buyers, saving money may be more important than saving the planet.

In a 2013 customer survey, J.D. Power found that environmental impact ranked low on consumers' list of priorities.

Fuel economy, on the other hand, was the top factor for purchasing a non-premium car, and the third most important reason for purchasing a premium one.

There are many reasons for buying an electric car or plug-in hybrid, and the environment is just one of them. As well as fuel savings, many different incentives give drivers of green cars other perks.

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Buyers of plug-in hybrids and electric cars can take advantage of a $7,500 Federal income-tax credit--as well as additional state and local cost incentives--while California drivers can use the state's high-occupancy vehicle lanes without passengers.

"Early adopters" may also be interested in the newness of plug-ins. They're willing to wait on line for the latest iPhone, so they're also willing to pay for the latest automotive technology.

Green cars can also serve as billboards for their drivers' values.

2012 Toyota Prius Plug-In Hybrid - production model

2012 Toyota Prius Plug-In Hybrid - production model

Being seen as green can be just as important to consumers as actually mitigating environmental impact, and a hybrid or increasingly an electric car is great way to advertise that.

However, such "uber greens" make up only a small percentage of the car-buying population. And plug-in car sales still make up a bit less than 1 percent of total vehicle volume in the U.S.

How would you get that number higher? What's the right way for dealers to move more green cars?

Leave us your thoughts in the Comments below.

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