Letter sent to st. John's Ambulance

I would like to know if you have a policy on the use of sirens? It appears to me that the ambulances keep their sirens on whenever they are out on the streets regardless of the emergency of the call. I do not understand why they would need to have their sirens on unless they actually need to get somewhere quick. I very often see ambulances driving at ridiculously slow speed in no rush to get through traffic or indeed get pass other cars on the road. Perhaps the ambulance drivers have become deaf from all those sirens and can no longer hear when they are on. Being in the medicine field you should be aware of the known the effects of loud noise. May I also remind you that there is a school right next to the road where all the ambulances pass to get to and from the hospital and perhaps you should take greater care when passing so not to damage the hearing of the kids.