It seems like what she was saying is that if the people who own and use the common resource have the ability to create rules and enforce them, then they can avoid a tragedy of the commons. I'd totally agree with that, you need some way to govern the resource.
About freeing up street space, I'd be curious to see some kind of statistics about how many lyft drivers were headed that way anyway and just pick up passengers vs. how many are providing a taxi-like service. Is there a way in the lyft or uber software as a driver to say that you're only looking for passengers going from one location to another location?
It seems like slugging is more likely to provide those benefits.
I am sorry to say that I do not have the statistics that you are looking for.
[1] http://en.wikipedia.org/wiki/Elinor_Ostrom