The day the subways, lightrail, buses, and trams are run by private enterprises and are not subject to the political whims of the unions and elected officials, then I might consider giving the concept a test run.
Introducing competitive environment, on the other hand, would.
In the last 15 years for U.S. transit:
* 2005 New York City transit strike
* 2007 Orange County transit strike
* 2010 Spirit Airlines Pilot Strike (U.S.)
What does private enterprise need to improve as it currently stands? The government subsidizes transit to such an extent that private players stay out and any hint of a profitable line is look unfavorably upon by government players that they ban it or try to robustly oppose it; examples include Google Bus', and Jitney's in New York.