@Rath: Another problem with hydrogen vehicles is that they're 3-4 times less efficient than electric vehicles. It goes electricity->hydrogen->back to electricity, with conversion losses accumulating throughout.
Compressed air cars are extremely doubtful right now... According to wikipedia, the best prototype ran for just 7.22 km on a charge. As with hydrogen and batteries, compressed air is just a means of storing energy, which means this is just another kind of electric vehicle.
As for battery-powered electric vehicles, it's good to note that they're only as ecological as the power stations which charge them. All countries should invest in renewable electricity sources, as opposed to coal which is currently the biggest source of electricity.
Even nuclear power is preferable if electricity demand increases a lot due to high numbers of electrical vehicles. It can't be stressed enough... coal is the dirtiest form of energy, both in terms of greenhouse gases and radiation (which isn't captured by "clean coal" tech). Renewables would be much better though.
Best of all would be for people to reduce usage of cars, and rely on public transportation as much as possible. Cars are very energy intensive and people are too dependent on them. This dependency is what makes us (as a civilization) oil addicts. We'll keep drilling and burning oil until it's too expensive (which will happen well before it runs out by the way). Will we have time to change our habits and/or technologies enough until then?
My Mario Kart Wii friend code: 2707-1866-0957
