I believe this is illegal in my country (Netherlands). Also, the emergency services here can transmit a wide band FM signal with the siren sound, so you hear it playing over your radio when they come close.
I have never heard of this (Wide Band FM Siren Noise) and I think it's a fantastic idea. Why don't we do this in the US?
How would you hear the commercials?
Specifically: how would we hear the commercials from accident injury lawyers?