Less the ticket, I've had that happen to me quite a few times taking the back roads to work. They turn on their red lights either while they're slowing down or when you're only a few car lengths in front of them still doing the speed limit and you absolutely wouldn't be able to stop infront of the bus. There's nothing you can do but keep going unless you feel like stoping beside or past the school bus

It just sucks that an ass cop was there to ticket him for that.
All I can suggest is talk to the prosecutor and explain the situation.