by or with

[chrysanthemum]

Do you say I go to school on schoolbus or by schoolbus?

[M.Andrew]

To go somewhere "by bus" refers to the method of transportation (vs. by car)

Where are you right now? "I'm on the bus." This refers to your current location.

[Rover_KE]

'I'm going to school on the school bus.'

School bus is two words.

Rover

[emsr2d2]

I go/travel to school by bus.
I go/travel to school on the school bus.

I realise that's confusing but it's mainly because the phrase "by bus" is a generally recognised phrase. "By school bus" is not recognised in the same way.

[Rover_KE]

Ems has made a good point.

In fact, if anything goes before bus we say on it.

'I'm going to Accrington on the Manchester bus; it gets there quicker.'

'The miners go to work on their special bus.'

Rover