Hybrid vehicles offer an attractive compromise: excellent fuel efficiency and lower emissions in a gasoline powered car. RELATED LINKS Green Living

The standard gasoline burning auto engine has been the king of the road for four generations, but with oil supplies shrinking and global air pollution worsening, researchers and manufacturers have been increasingly experimenting with more efficient, eco-friendly vehicles. One possible alternative, which attempts to balance issues of power, fuel efficiency and cleanliness, is called a hybrid. Just what are hybrids, and what advantages do they offer over other types of vehicles?

Barry Catlett reports on the auto industry for the Automotive Satellite Television Network. An award-winning journalist with more than 20 years' experience in television news departments across the country, Catlett has a love of cars that began with driving a pedal-operated model when he was three. Here he gives us the scoop on the new hybrid vehicles:

• Gas and electric. A hybrid vehicle is one that combines a small gasoline engine with an electric motor. There is often a generator in the system as well. The gasoline engine and the electric motor both work to power the vehicle, sometimes in tandem and sometimes individually.

• Mileage and Emissions. Because the gasoline engine is assisted by the electric motor and is therefore not doing all the work, the vehicles get more miles per gallon of gas, and the emissions are also much lower. The power boost from the electric motor also means that the gas engine can be smaller than in a typical car.

• Gas stations. One of the principal problems with the attempted rollout of zero-emissions electric vehicles is the lack of adequate recharging stations across the country. But since hybrid vehicles burn the same unleaded gas as most other autos, there's no need for the expense of an all-new fuel station infrastructure. We can keep using existing gas stations, and simply fill our tanks less often.

• Friendly and familiar. Hybrid vehicles are better for the environment than standard cars, since they use far less gasoline, getting up to 60 miles per gallon. Unlike all-electric vehicles, they also feel much like a regular car to the driver. Catlett likens the experience of driving a hybrid to that of driving a four-cylinder car, which means that most people will be able to drive one without even having to think about the fact that they're saving fuel and helping the environment.

Office of Transportation Technologies: Hybrid Electric Vehicle Program
www.ott.doe.gov/hev/

Ford Motor Company: Hybrid Electric Vehicles
www.ford.com/en/ourVehicles/environmentalVehicles/hybridElectricVehicles/default.htm

The Toyota Prius
www.toyota.com/html/shop/vehicles/prius/index.html

US Department of Energy Clean Cities: What is a Hybrid Electric Vehicle?
www.ccities.doe.gov/vbg/consumers/hybrid.shtml

Fuel Economy.gov: Hybrid Vehicle News
www.fueleconomy.gov/feg/hybrid_news.shtml