Weird, but somewhat relevant question (given that self driving capabilities combined with buses can potentially disrupt public transportation in urban areas): w

Weird, but somewhat relevant question (given that self driving capabilities combined with buses can potentially disrupt public transportation in urban areas): why do we even allow anything that's not a bus (say, 10+ passenger) or industrial vehicle on the road? The downsides of such a thing seem small. 1. There would be less traffic 2. The speed limit could be raised 3. Due to higher occupancy, more people could go to places, faster. 4. Cheaper per person (maybe) than most other forms of public transportation 5. High density areas can have fleets of buses go there, express. This would have only a little overhead compared to driving your own vehicle, yet would be substantially cheaper.