In the past decade there has been a great deal of worrying about what will happen when the world's oil supply becomes depleted. The main reason for concern is that almost all of the automobiles in use now require an oil based gasoline to run their internal-combustion engines. In the next few decades it is predicted that all of the world's oil will have already been mined, and combustion engines will be unable to function. For this reason many companies such as Ford, Mercedes-Benz, Chrysler, Toyota, BMW, and others have started to create engines that do not require oil based...
of fuel needed, it also dramatically lowers the amount of pollution that the exhaust emits.

With these three engines, the amount of gasoline that is used will dramatically decrease. The problem now is distributing these engines all around the world, and convincing people to purchase cars that have these smaller engines, instead of cars that use gasoline very quickly. Given that cars with small motors that get good gas mileage aren't as popular as vehicles with large motors that use gas quickly, it will take a very long time for people to adapt to buying future gasoline saving vehicles.