Motor vehicles also produce more than 30 percent of all emissions of carbon dioxide and nitrogen oxides. Excess carbon dioxide in the atmosphere is the number one cause of global warming. Nitrogen oxides, among the pollutants that contribute to ground-level ozone, also cause acid rain, which kills fish, damages vegetation, and chokes waterways with algae. Many promising clean-car technologies are in development, but most won't be ready for widespread use for a few years. The technology to build hybrid gasoline-electric vehicles, which can be used everywhere and by anyone, without access to special refueling equipment, is available now.
Hybrids operate on a combination of electricity and one other source of power.
In the immediate future, a small gasoline-powered engine is the best prospect for the mass market, but in the longer run the secondary power source could be natural gas, fuel cells or other clean technologies. You can still fill up your car at any gas station, although you'll make a lot fewer trips, since hybrid cars average 60 miles per gallon. There is no reason that hybrid cars cannot be engineered to provide the same performance and convenience as today's vehicles with much improved efficiency and reduced pollution. You'll get the same power, acceleration and braking. Hybrids tend to be quieter than the average car, since the engine only operates when the car is moving, and to accelerate more smoothly, because many hybrids have no transmission so there are no abrupt gear shifts.