I first read about Curitiba maybe 4-5 years ago, probably in _Natural Capitalism_ by Levins et al (since reading _Shoes Behind the Door_ and some other stuff, I've become a lot more skeptical of Levins as a source, but have no reason to suspect the accuracy of this description). Knocked my socks off, it made so much sense. Why build rail lines when you've already got pavement? Just build your system around reasonable buses and everything is great. This blog entry covers the details adequately: you don't pay on entering the bus, but on entering the terminal. Level entry to the bus. Etc. All the stuff that happens with light rail/subways/etc., but in a bus.
The photos also do a great job of bringing the zoning home, which is a big chunk of what makes a public transportation system viable.
I love that the blogger makes specific suggestions for adapting to LA! Of course, I don't know LA well at all, having only visited a half dozen or so times and mostly just passing through so I cannot speak to whether the blogger makes sense or not.
_This_ is the kind of discussion we need a whole lot more of. A _whole_ lot more of.
The blog in general is absolutely worth reading. Particularly his mapping of the drop in car sales to fleet economy for the maker. Sweet.