Yeah I have witnessed that in Sao Paulo and Vilnius, it's an extremely satisfying transportation system (though illegal indeed). I wonder if the high-tech-ness brings such an advantage here.
I used to live off Flatbush in Lefferts Gardens, those vans were fantastic. If they could somehow take hold there are a lot of other routes that would work well.
Doubtless it occurs in numerous other cities, though i'd always assumed it was a developing countries phenomenon (cue joke about Queens).