whats a training bus?

Question

I frequently Santa Monica and I have several times
see buses going down 2nd street with a stickers on the bus
saying "Training bus"
now HOW DO YOU TRAIN a BUS? don't you just get in the bus
and drive it?

Answer 1

You wish! Even bus drivers have to go to school, just as you went to driving school. In fact, bus drivers, due to the number of lives in his hands, need to be MORE trained than your average driver!

Answer 2

That's nothing, over here (GB) you see articulated lorries with giant L-plates on the back trying to manoeuvre through towns.