no, I'm wondering if you had an electric van/bus service driving on regular streets (run by the transit agency or a private company), what efficiency level would be acceptable? say the EV van/bus could be as energy efficient as a typical bus at X number of passengers and as efficient as a typical light rail at Y number of passenger, should the service be used in a scenario where it will average X through the day of operation, or should the service only be implemented in places where it can average Y throughout the day?

I ask because we may get to a point in the coming years where buses can become autonomous and thus the size can be varied by cities (without having to worry about the driver cost), so that more frequent but less efficient buses/vans can be used for a route, or less frequent but more efficient buses/vans can be used.

to give another scenario:

you have two bus/van services

1. arrives every 5 minutes, averages 5 passengers per vehicle
2. arrives every 10 minutes, averages 10 passengers per vehicle.

obviously the 2nd option uses half as much energy per passenger moved, but the difference between 5min and 10min headways can be a big deciding factor in whether or not people ride transit. so 5min headway may get more people to stop driving their cars and take the bus instead. so maybe the scenario changes to:

1. arrives every 5min, averages 8 passengers per vehicle
2. arrives every 10min, averages 10 passengers per vehicle

now, the 1st option is still less energy-efficient per passenger, but it is stopping people from driving their own cars, which has benefits in terms of energy consumption bus also in other indirect ways like pollution, traffic noise, parking that could be turned into green-space or bike lanes, etc.