2 . Hybrid cars, also called hybrid electric vehicles （HEVs）, are cars that use more than one source of energy to run. They differ from the majority of cars on the road today in several ways. The main difference is that HEVs run on gasoline and electricity. An HEV car has a battery-powered motor as well as an engine that runs on gasoline.

A hybrid car is a bit more expensive to produce than a regular car even though its engine is smaller. The reason for the greater expense is that the engine is more complex. It has specialized mechanisms that allow it to operate using gasoline and electric power. It also contains a computer that works differently from those of regular cars. Even though it is more expensive to purchase, it costs less to own than gas-powered cars. When an HEV car is at a stoplight or going at a speed below 15 miles per hour, its special computer tells it to run just on electric power. When the computer senses that the car needs more power, it puts the gasoline engine back to work. The computer is constantly deciding whether the car will use electricity, gas, or a combination of the two.

Because the HEV has electric power to help it run, it uses much less fuel than most cars. In fact hybrid cars are the most fuel-efficient cars that exist today. They can get from 50 to 60 miles per gallon on average. The high mileage saves money for the car owner and conserves precious supplies of petroleum. Hybrid cars help the environment in other ways too. For example, when

the HEV is using electric power, it does not send out poisonous smoke that pollute the air.

Despite the differences between hybrid cars and regular cars, HEVs offer the same feel as regular cars. They handle the same way and speed up and stop in the same way too. HEVs, though, are generally smaller than gasoline-powered cars. Their rounded, aerodynamic frame helps add to their fuel efficiency but unfortunately does not add to the amount of space inside the vehicle.