Zero emission vehicles have no tailpipe emissions, no evaporative emissions, no emissions from gasoline, and no on-board emission-control systems that can deteriorate over time. In essence, these vehicles are non-polluting.
Zero emission vehicles can be powered by electricity, fuel cells, or solar power. Traditional zero-emission vehicles include bicycles, roller skates, skateboards, and feet. Transportation powered by animals (such as horses, cattle, goats, camels or other beasts of burden) are not considered zero emission because of methane produced by such grazing animals. But that can be seen as just a little bit picky.