The environmental concerns have even hit the stars of Hollywood: during the recent academy awards the gaudy limousines were not the most prestigious way of arriving and hitting the red carpet, it was coming in a hybrid car.
A hybrid car has two engines working under the hood. The first is an electric motor and the second is the good old gasoline engine. When your car is running at a constant speed or when it is standing but the engine is running, the gasoline engine automatically shuts off and the electricity part takes on. This helps a lot when you are stuck in traffic jams and your engine is running — lots of pollution is caused during the traffic jams. When you need to accelerate, the gasoline engine pumps in the requisite gas, and then again hands the control over to the electric engine.
This way the consumption of fossil fuel is cut down to almost half and so is the emission level. The noise pollution comes down too.