About pollution, what about troleys, trams and S-bahns then?
Take a look at this: http://en.wikipedia.org/wiki/Zurich_model
And take Basel as a small city(~170k population) with a very good public transportation system.
The models are already out there and working nicely, other cities just have to emulate them.
> The models are already out there and working nicely, other cities just have to emulate them.
That's OK if you're starting from scratch, but very few new city-scale developments are started from a clean sheet, at least here in the UK. I don't think many people would look kindly on demolishing historic city centres just to build new tramways or light rail...
The models are already out there and working nicely, other cities just have to emulate them.