Here is what I recall from my reading a few years ago. According to Ontario Traffic Act, you are supposed to give road to emergency vehicles:
1. At stop sign, an emergency vehicle has exception by law to go through without stopping.
2. Upon approaching an emergency vehicle( even stopped at side) on highway, try to slow down and move out of an emergency vehicle's lane or adjacent lane if safe to do so.
Fail to do so, you can get a fine with ticket.