> Public bus systems should really be exploring a smaller vehicle model more

I asked someone from my local bus service once. Their answer was that it's not economically viable for the public bus service, as the only major saving was fuel cost and the extra services don't provide enough revenue to offset the employee cost (otherwise they could service it with the large normal busses).

So basically this becomes viable with increased ticket prices or self-driving busses. The technology isn't quite there yet for the latter, and governments don't like price differentiation in bus lines.

* Maintenance cost per line might go slightly down, but apparantly overal it's more expensive because they need to maintain technicians and parts for more models.