| Established alternatives for some aspects of | | | | car until boiler pressure was available (although the |
| automobile use include public transit (buses, | | | | newer models could achieve this in well under a |
| trolleybuses, trains, subways, monorails, | | | | minute). It has the advantage of being able to |
| tramways), cycling, walking, rollerblading, | | | | produce very low emissions as the combustion |
| skateboarding, horseback riding and using a | | | | process can be carefully controlled. Its |
| velomobile. Car-share arrangements and carpooling | | | | disadvantages include poor heat efficiency and |
| are also increasingly popular–the U.S. market | | | | extensive requirements for electric |
| leader in car-sharing has experienced double-digit | | | | auxiliaries.[23].free articles directory |
| growth in revenue and membership growth | | | | Air |
| between 2006 and 2007, offering a service that | | | | Main article: Compressed-air car |
| enables urban residents to "share" a vehicle rather | | | | A compressed air car is an alternative fuel car |
| than own a car in already congested | | | | that uses a motor powered by compressed air. |
| neighborhoods.[42] Bike-sharefree articles | | | | The car can be powered solely by air, or by air |
| directorysystems have been tried in some | | | | combined (as in a hybrid electric vehicle) with |
| European cities, including Copenhagen and | | | | gasoline/diesel/ethanol or electric plant and |
| Amsterdam. Similar programs have been | | | | regenerative braking. Instead of mixing fuel with |
| experimented with in a number of U.S. Cities.[43] | | | | air and burning it to drive pistons with hot |
| Additional individual modes of transport, such as | | | | expanding gases; compressed air cars use the |
| personal rapid transit could serve as an alternative | | | | expansion of compressed air to drive their |
| to automobiles if they prove to be socially | | | | pistons. Several prototypes are available already |
| accepted.[44] | | | | and scheduled for worldwide sale by the end of |
| Steamfree articles directory Main article: steam | | | | 2008, though this has not happened as of January |
| car | | | | 2009. Companies releasing this type of car include |
| Steam power, usually using an oil- or gas-heated | | | | Tata Motors and Motor Development International |
| boiler, was also in use until the 1930s but had the | | | | (MDI). |
| major disadvantage of being unable to power the | | | | |