Given the "power" of the internet, we should be able to schedule ad-hoc rides on the cheap.
Paxis - Taxis that run on a public on-demand schedule? Pack those cars up with people who have similar sources and destinations to be more efficient. I guess these are actually the same as Shuttles. Oops!
Practus - "Buses" that use Drivers-Ed students. The students get practice by actually driving people around. The person riding shotgun should know two things. (1) Directions. (2) How to drive. Finally, the car may be one of those cars with a passenger-side brake.
Come on!