An environmentally-friendly car is any model of automobile that is designed to cut down on energy consumption, carbon emissions, and other types of waste that can harm the environment. The methods through which a particular vehicle accomplishes these goals will vary according to the manufacturer; some manufacturers make the engines run more efficiently to cut down on emissions, while others feature alternative fuels that burn more cleanly. Still other environmentally-friendly car models run on electricity, or combine electric power with gasoline-powered engines. Some cars feature parts that are recyclable, or batteries that are rechargeable and feature a longer life than traditional car batteries.
The hybrid vehicle is one of the more popular environmentally-friendly car models available. This type of automobile is called a hybrid because it combines two or more power sources, usually a battery and a gasoline-powered engine. The car will very often run on battery power during low speed trips around town, and it will use the gasoline-powered engine at higher speeds or in situations in which more power is needed. Starting from a dead stop will often require the use of the gasoline engine, while driving at a constant speed for long periods of time can be done with the battery rather than the gasoline. This helps cut down on carbon emissions from the gasoline engine without sacrificing too much power.
Other alternative fuel sources include solar power, magnetic power, and even wind power. None of these models are commercially available on a large scale, but developments in alternative fuel sources have become increasingly important over the course of decades not only for environmental purposes, but also for budgetary purposes: as the demand for oil increases and the availability decreases, the cost of gasoline rises to almost prohibitive levels. Environmentally-friendly car models seek to reduce one's dependence on oil as a primary fuel source.
Other environmentally-friendly car designs do not use alternative fuel sources, but instead strive to use far less gasoline than traditional automobiles. Some cars can run on as little as a pint of gasoline, as opposed to traditional models that require several gallons of gasoline to be run for any lengthy period of time. By using less fuel, an environmentally-friendly car will reduce the amount of carbon emissions the car creates without necessarily sacrificing the overall performance of the car. The most environmentally-friendly car, of course, is one that is not driven excessively, so a traditional car can be more environmentally friendly simply by being used less.