Smart Phone app - input where you want to go. GPS tells the dispatch server where you are. Gives directions for public transportation from where you are to where you want to go. When you arrive at the bus stop you hit ready. The dispatch system updates the estimate of your travel time and dispatches vehicles (buses, or vans) depending on the expected passenger load.
This system would be for low volume ridership routes. Instead of empty buses running at night smaller vans might be used instead and empty runs avoided. Periodic traffic patterns could be used to forecast demand.
The fact that you are using your cell phone cuts down on the likelihood of system abuse.