Hardly. First, there's a lot of research into cleaner cars. A modern car produces very little emissions that count towards unclean air. Of course, there's carbo

Hardly. First, there's a lot of research into cleaner cars. A modern car produces very little emissions that count towards unclean air. Of course, there's carbon, but that doesn't cause unclean or unhealthy air. Second, the new variable you're thinking of is called "externalities" and isn't all that new. A common way to offset it is http://en.wikipedia.org/wiki/Pigovian_tax http://en.wikipedia.org/wiki/Pigovian_tax - a such is leveraged on gasoline in most countries, including the US, although to a much steeper degree in Europe. Expensive gas is a major driver towards more fuel efficient cars, hybrids and electric cars. All brought to you (mostly) by a profit driven capitalist system. The reason gasoline hasn't disappeared in favour of more environmentally friendly alternatives is that it's an insanely effective way of storing and transporting vast quantities of energy. Even with the steep taxes in Europe, no-one has been able to come up with a better alternative -- yet. I am certain this will change soon.