By Brian Clark Howard
That's because the really cool thing about them is under the hood: Hybrid vehicles combine the internal combustion engine of a conventional vehicle with the battery and motor of an electric car. The two power sources can be combined in a couple of different ways: In a parallel hybrid, both the gasoline engine and the electric motor are connected to the transmission, and so both can power the car. In a series hybrid, the gasoline engine's power is converted to electrical power by a generator. It can charge the batteries or drive the motor, but it can't power the transmission directly. Either way, hybrid cars leverage gas and electric power to achieve the best of both worlds good performance and a fuel economy between 40-70 mph. Because they achieve better mileage than conventional models in the same size class, hybrids emit far fewer of the pollutants that form smog, trap heat in the atmosphere, and aggravate health problems such as asthma and bronchitis. Which perhaps helps to explain why there are now 62,000 hybrids on the road. Buying a fuel-efficient hybrid is one of the most effective actions you can take against global warming. And one of the most cost effective, too: You'll be rewarded with a federal income tax credit of up to $3,400.